Remove extra screen refreshes and obsolete box

2022-04-09 17:18:13 -04:00
1050 changed files with 27764 additions and 39761 deletions
@@ -14,10 +14,6 @@ end_of_line = lf
 indent_style = space
 indent_size = 2

-[{*.py}]
-indent_style = space
-indent_size = 4
-
-[{*.conf,*.sublime-project}]
+[{*.py,*.conf,*.sublime-project}]
 indent_style = tab
 indent_size = 4
@@ -1,178 +0,0 @@
-name: 🪲 Report a bug
-description: Create a bug report to help improve Marlin Firmware
-title: "[BUG] (bug summary)"
-body:
-  - type: markdown
-    attributes:
-      value: >
-        Do you want to ask a question? Are you looking for support? Please use one of the [support links](https://github.com/MarlinFirmware/Marlin/issues/new/choose).
-
-  - type: markdown
-    attributes:
-      value: |
-        **Thank you for reporting a bug in Marlin Firmware!**
-
-        ## Before Reporting a Bug
-
-        - Read and understand Marlin's [Code of Conduct](https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.1.x/.github/code_of_conduct.md). You are expected to comply with it, including treating everyone with respect.
-
-        - Test with the [`bugfix-2.1.x` branch](https://github.com/MarlinFirmware/Marlin/archive/bugfix-2.1.x.zip) to see whether the issue still exists.
-
-        ## Instructions
-
-        Please follow the instructions below. Failure to do so may result in your issue being closed. See [Contributing to Marlin](https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.1.x/.github/contributing.md) for additional guidelines.
-
-        1. Provide a good title starting with [BUG].
-        2. Fill out all sections of this bug report form.
-        3. Always attach configuration files so we can build and test your setup.
-
-  - type: dropdown
-    attributes:
-      label: Did you test the latest `bugfix-2.1.x` code?
-      description: >-
-        Always try the latest code to make sure the issue you are reporting is not already fixed. To download
-        the latest code just [click this link](https://github.com/MarlinFirmware/Marlin/archive/bugfix-2.1.x.zip).
-      options:
-        - Yes, and the problem still exists.
-        - No, but I will test it now!
-    validations:
-      required: true
-
-  - type: markdown
-    attributes:
-      value: |
-        # Bug Details
-
-  - type: textarea
-    attributes:
-      label: Bug Description
-      description: >-
-        Describe the bug in this section. Tell us what you were trying to do and what
-        happened that you did not expect. Provide a clear and concise description of the
-        problem and include as many details as possible.
-
-        When pasting formatted text don't forget to put ` ``` ` (on its own line) before and after to make it readable.
-      placeholder: |
-        Marlin doesn't work.
-    validations:
-      required: true
-
-  - type: input
-    attributes:
-      label: Bug Timeline
-      description: Is this a new bug or an old issue? When did it first start?
-
-  - type: textarea
-    attributes:
-      label: Expected behavior
-      description: >-
-        What did you expect to happen?
-      placeholder: I expected it to move left.
-
-  - type: textarea
-    attributes:
-      label: Actual behavior
-      description: What actually happened instead?
-      placeholder: It moved right instead of left.
-
-  - type: textarea
-    attributes:
-      label: Steps to Reproduce
-      description: >-
-        Please describe the steps needed to reproduce the issue.
-      placeholder: |
-        1. [First Step] ...
-        2. [Second Step] ...
-        3. [and so on] ...
-
-  - type: markdown
-    attributes:
-      value: |
-        # Your Setup
-
-  - type: input
-    attributes:
-      label: Version of Marlin Firmware
-      description: "See the About Menu on the LCD or the output of `M115`. NOTE: For older releases we only patch critical bugs."
-    validations:
-      required: true
-
-  - type: input
-    attributes:
-      label: Printer model
-      description: Creality Ender 3, Prusa mini, or Kossel Delta?
-
-  - type: input
-    attributes:
-      label: Electronics
-      description: Stock electronics, upgrade board, or something else?
-
-  - type: input
-    attributes:
-      label: Add-ons
-      description: Please list any hardware add-ons that could be involved.
-
-  - type: dropdown
-    attributes:
-      label: Bed Leveling
-      description: What kind of bed leveling compensation are you using?
-      options:
-        - UBL Bilinear mesh
-        - ABL Bilinear mesh
-        - ABL Linear grid
-        - ABL 3-point
-        - MBL Manual Bed Leveling
-        - No Bed Leveling
-
-  - type: dropdown
-    attributes:
-      label: Your Slicer
-      description: Do you use Slic3r, Prusa Slicer, Simplify3D, IdeaMaker...?
-      options:
-        - Slic3r
-        - Simplify3D
-        - Prusa Slicer
-        - IdeaMaker
-        - Cura
-        - Other (explain below)
-
-  - type: dropdown
-    attributes:
-      label: Host Software
-      description: Do you use OctoPrint, Repetier Host, Pronterface...?
-      options:
-        - SD Card (headless)
-        - Repetier Host
-        - OctoPrint
-        - Pronterface
-        - Cura
-        - Same as my slicer
-        - Other (explain below)
-
-  - type: markdown
-    attributes:
-      value: |
-        # Attachments
-
-  - type: checkboxes
-    attributes:
-      label: Don't forget to include
-      options:
-        - label: A ZIP file containing your `Configuration.h` and `Configuration_adv.h`.
-          required: true
-
-  - type: markdown
-    attributes:
-      value: |
-        ### Optional items to include:
-        - 'Log output from the host. (`M111 S247` for maximum logging.)'
-        - Images or videos demonstrating the problem, if it helps to make it clear.
-        - A G-Code file that exposes the problem, if not affecting _all_ G-code.
-
-  - type: textarea
-    attributes:
-      label: Additional information & file uploads
-      description: >-
-        If you've made any other modifications to the firmware, please describe them in detail.
-
-        When pasting formatted text don't forget to put ` ``` ` (on its own line) before and after to make it readable.
@@ -1,20 +0,0 @@
-blank_issues_enabled: false
-contact_links:
-  - name: 📖 Marlin Documentation
-    url: https://marlinfw.org/
-    about: Lots of documentation on installing and using Marlin.
-  - name: 👤 MarlinFirmware Facebook group
-    url: https://www.facebook.com/groups/1049718498464482
-    about: Please ask and answer questions here.
-  - name: 🕹 Marlin on Discord
-    url: https://discord.gg/n5NJ59y
-    about: Join the Discord server for support and discussion.
-  - name: 🔗 Marlin Discussion Forum
-    url: https://reprap.org/forum/list.php?415
-    about: A searchable web forum hosted by RepRap dot org.
-  - name: 📺 Marlin Videos on YouTube
-    url: https://www.youtube.com/results?search_query=marlin+firmware
-    about: Tutorials and more from Marlin users all around the world. Great for new users!
-  - name: 💸 Want to donate?
-    url: https://www.thinkyhead.com/donate-to-marlin
-    about: Please take a look at the various options to support Marlin Firmware's development financially!
@@ -1,44 +0,0 @@
-name: ✨ Request a feature
-description: Request a new Marlin Firmware feature
-title: "[FR] (feature summary)"
-labels: 'T: Feature Request'
-body:
-  - type: markdown
-    attributes:
-      value: >
-        Do you want to ask a question? Are you looking for support? Please use one of the [support links](https://github.com/MarlinFirmware/Marlin/issues/new/choose).
-
-  - type: markdown
-    attributes:
-      value: >
-        **Thank you for requesting a new Marlin Firmware feature!**
-
-        ## Before Requesting a Feature
-
-        - Read and understand Marlin's [Code of Conduct](https://github.com/MarlinFirmware/Marlin/blob/master/.github/code_of_conduct.md). You are expected to comply with it, including treating everyone with respect.
-
-        - Check the latest [`bugfix-2.1.x` branch](https://github.com/MarlinFirmware/Marlin/archive/bugfix-2.1.x.zip) to see if the feature already exists.
-
-        - Before you proceed with your request, please consider if it is necessary to make it into a firmware feature, or if it may be better suited for a slicer or host feature.
-
-  - type: textarea
-    attributes:
-      label: Is your feature request related to a problem? Please describe.
-      description: A clear description of the problem (e.g., "I need X but Marlin can't do it [...]").
-
-  - type: textarea
-    attributes:
-      label: Are you looking for hardware support?
-      description: Tell us the printer, board, or peripheral that needs support.
-
-  - type: textarea
-    attributes:
-      label: Describe the feature you want
-      description: A clear description of the feature and how you think it should work.
-    validations:
-      required: true
-
-  - type: textarea
-    attributes:
-      label: Additional context
-      description: Add any other context or screenshots about the feature request here.
@@ -34,11 +34,8 @@ This project and everyone participating in it is governed by the [Marlin Code of

 We have a Message Board and a Facebook group where our knowledgable user community can provide helpful advice if you have questions.

- [Marlin Documentation](https://marlinfw.org) - Official Marlin documentation
- Facebook Group ["Marlin Firmware"](https://www.facebook.com/groups/1049718498464482/)
- RepRap.org [Marlin Forum](https://forums.reprap.org/list.php?415)
- Facebook Group ["Marlin Firmware for 3D Printers"](https://www.facebook.com/groups/3Dtechtalk/)
- [Marlin Configuration](https://www.youtube.com/results?search_query=marlin+configuration) on YouTube
+* [Marlin RepRap forum](https://reprap.org/forum/list.php?415)
+* [MarlinFirmware on Facebook](https://www.facebook.com/groups/1049718498464482/)

 If chat is more your speed, you can join the MarlinFirmware Discord server:

@@ -53,13 +50,13 @@ If chat is more your speed, you can join the MarlinFirmware Discord server:

 This section guides you through submitting a Bug Report for Marlin. Following these guidelines helps maintainers and the community understand your report, reproduce the behavior, and find related reports.

-Before creating a Bug Report, please test the "nightly" development branch, as you might find out that you don't need to create one. When you are creating a Bug Report, please [include as many details as possible](#how-do-i-submit-a-good-bug-report). Fill out [the required template](ISSUE_TEMPLATE/bug_report.yml), the information it asks for helps us resolve issues faster.
+Before creating a Bug Report, please test the "nightly" development branch, as you might find out that you don't need to create one. When you are creating a Bug Report, please [include as many details as possible](#how-do-i-submit-a-good-bug-report). Fill out [the required template](issue_template.md), the information it asks for helps us resolve issues faster.

 > **Note:** Regressions can happen. If you find a **Closed** issue that seems like your issue, go ahead and open a new issue and include a link to the original issue in the body of your new one. All you need to create a link is the issue number, preceded by #. For example, #8888.

 #### How Do I Submit A (Good) Bug Report?

-Bugs are tracked as [GitHub issues](https://guides.github.com/features/issues/). Use the New Issue button to create an issue and provide the following information by filling in [the template](ISSUE_TEMPLATE/bug_report.yml).
+Bugs are tracked as [GitHub issues](https://guides.github.com/features/issues/). Use the New Issue button to create an issue and provide the following information by filling in [the template](issue_template.md).

 Explain the problem and include additional details to help maintainers reproduce the problem:

@@ -91,12 +88,12 @@ Include details about your configuration and environment:

 This section guides you through submitting a suggestion for Marlin, including completely new features and minor improvements to existing functionality. Following these guidelines helps maintainers and the community understand your suggestion and find related suggestions.

-Before creating a suggestion, please check [this list](https://github.com/MarlinFirmware/Marlin/issues?q=is%3Aopen+is%3Aissue+label%3A%22T%3A+Feature+Request%22) as you might find out that you don't need to create one. When you are creating an enhancement suggestion, please [include as many details as possible](#how-do-i-submit-a-good-feature-request). Fill in [the template](ISSUE_TEMPLATE/feature_request.yml), including the steps that you imagine you would take if the feature you're requesting existed.
+Before creating a suggestion, please check [this list](#before-submitting-a-suggestion) as you might find out that you don't need to create one. When you are creating an enhancement suggestion, please [include as many details as possible](#how-do-i-submit-a-good-enhancement-suggestion). Fill in [the template](issue_template.md), including the steps that you imagine you would take if the feature you're requesting existed.

 #### Before Submitting a Feature Request

 * **Check the [Marlin website](https://marlinfw.org/)** for tips — you might discover that the feature is already included. Most importantly, check if you're using [the latest version of Marlin](https://github.com/MarlinFirmware/Marlin/releases) and if you can get the desired behavior by changing [Marlin's config settings](https://marlinfw.org/docs/configuration/configuration.html).
-* **Perform a [cursory search](https://github.com/MarlinFirmware/Marlin/issues?q=is%3Aopen+is%3Aissue+label%3A%22T%3A+Feature+Request%22)** to see if the enhancement has already been suggested. If it has, add a comment to the existing issue instead of opening a new one.
+* **Perform a [cursory search](https://github.com/MarlinFirmware/Marlin/issues?q=is%3Aissue)** to see if the enhancement has already been suggested. If it has, add a comment to the existing issue instead of opening a new one.

 #### How Do I Submit A (Good) Feature Request?

@@ -119,7 +116,7 @@ Unsure where to begin contributing to Marlin? You can start by looking through t

 ### Pull Requests

-Pull Requests should always be targeted to working branches (e.g., `bugfix-2.1.x` and/or `bugfix-1.1.x`) and never to release branches (e.g., `2.0.x` and/or `1.1.x`). If this is your first Pull Request, please read our [Guide to Pull Requests](https://marlinfw.org/docs/development/getting_started_pull_requests.html) and Github's [Pull Request](https://help.github.com/articles/creating-a-pull-request/) documentation.
+Pull Requests should always be targeted to working branches (e.g., `bugfix-1.1.x` and/or `bugfix-2.0.x`) and never to release branches (e.g., `1.1.x`). If this is your first Pull Request, please read our [Guide to Pull Requests](https://marlinfw.org/docs/development/getting_started_pull_requests.html) and Github's [Pull Request](https://help.github.com/articles/creating-a-pull-request/) documentation.

 * Fill in [the required template](pull_request_template.md).
 * Don't include issue numbers in the PR title.
@@ -0,0 +1,35 @@
+<!--
+
+Have you read Marlin's Code of Conduct? By filing an Issue, you are expected to comply with it, including treating everyone with respect: https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.0.x/.github/code_of_conduct.md
+
+Do you want to ask a question? Are you looking for support? Please don't post here. Instead use one of the following options:
+
+- The Marlin Firmware forum at https://reprap.org/forum/list.php?415
+- The MarlinFirmware Facebook Group at https://www.facebook.com/groups/1049718498464482/
+- The MarlinFirmware Discord Server at https://discord.gg/n5NJ59y.
+
+Before filing an issue be sure to test the latest "bugfix" branch to see whether the issue is already addressed.
+
+-->
+
+### Description
+
+<!-- Description of the bug or requested feature -->
+
+### Steps to Reproduce
+
+<!-- If this is a Bug Report, please describe the steps needed to reproduce the issue -->
+
+1. [First Step]
+2. [Second Step]
+3. [and so on...]
+
+**Expected behavior:** [What you expect to happen]
+
+**Actual behavior:** [What actually happens]
+
+#### Additional Information
+
+* Include a ZIP file containing your `Configuration.h` and `Configuration_adv.h` files.
+* Provide pictures or links to videos that clearly demonstrate the issue.
+* See [How Can I Contribute](#how-can-i-contribute) for additional guidelines.
@@ -1,33 +1,23 @@
-<!--
+### Requirements

-Submitting a Pull Request
-
- Please fill out all sections of this form. You can delete the helpful comments.
- Pull Requests without clear information will take longer and may even be rejected.
- We get a high volume of submissions so please be patient during review.
-
-->
+* Filling out this template is required. Pull Requests without a clear description may be closed at the maintainers' discretion.

 ### Description

 <!--

-Clearly describe the submitted changes with lots of details. Include images where helpful. Initial reviewers may not be familiar with the subject, so be as thorough as possible. You can use MarkDown syntax to improve readability with bullet lists, code blocks, and so on. PREVIEW and fix up formatting before submitting.
+We must be able to understand your proposed change from this description. If we can't understand what the code will do from this description, the Pull Request may be closed at the maintainers' discretion. Keep in mind that the maintainer reviewing this PR may not be familiar with or have worked with the code recently, so please walk us through the concepts.

 -->

-### Requirements
-
-<!-- Does this PR require a specific board, LCD, etc.? -->
-
 ### Benefits

-<!-- What does this PR fix or improve? -->
+<!-- What does this fix or improve? -->

 ### Configurations

-<!-- Attach Configurations ZIP and any other files needed to test this PR. -->
+<!-- Attach any Configuration.h, Configuration_adv.h, or platformio.ini files needed to compile/test your Pull Request. -->

 ### Related Issues

-<!-- Does this PR fix a bug or fulfill a Feature Request? Link related Issues here. -->
+<!-- Whether this fixes a bug or fulfills a feature request, please list any related Issues here. -->
@@ -1,59 +0,0 @@
-#
-# bump-date.yml
-# Bump the distribution date once per day
-#
-
-name: Bump Distribution Date
-
-on:
-  schedule:
-    - cron: '0 */6 * * *'
-
-jobs:
-  bump_date:
-    name: Bump Distribution Date
-    if: github.repository == 'MarlinFirmware/Marlin'
-
-    runs-on: ubuntu-latest
-
-    steps:
-
-    - name: Check out bugfix-2.1.x
-      uses: actions/checkout@v2
-      with:
-        ref: bugfix-2.1.x
-
-    - name: Bump Date (bugfix-2.0.x)
-      run: |
-        # Inline Bump Script
-        if [[ ! "$( git log -1 --pretty=%B )" =~ ^\[cron\] ]]; then
-          DIST=$( date +"%Y-%m-%d" )
-          eval "sed -E -i 's/(#define +STRING_DISTRIBUTION_DATE) .*$/\1 \"$DIST\"/g' Marlin/src/inc/Version.h" && \
-          eval "sed -E -i 's/(#define +STRING_DISTRIBUTION_DATE) .*$/\1 \"$DIST\"/g' Marlin/Version.h" && \
-          git config user.name "${GITHUB_ACTOR}" && \
-          git config user.email "${GITHUB_ACTOR}@users.noreply.github.com" && \
-          git add . && \
-          git commit -m "[cron] Bump distribution date ($DIST)" && \
-          git push
-        fi
-        exit 0
-
-    - name: Check out bugfix-2.1.x
-      uses: actions/checkout@v2
-      with:
-        ref: bugfix-2.1.x
-
-    - name: Bump Date (bugfix-2.1.x)
-      run: |
-        # Inline Bump Script
-        if [[ ! "$( git log -1 --pretty=%B )" =~ ^\[cron\] ]]; then
-          DIST=$( date +"%Y-%m-%d" )
-          eval "sed -E -i 's/(#define +STRING_DISTRIBUTION_DATE) .*$/\1 \"$DIST\"/g' Marlin/src/inc/Version.h" && \
-          eval "sed -E -i 's/(#define +STRING_DISTRIBUTION_DATE) .*$/\1 \"$DIST\"/g' Marlin/Version.h" && \
-          git config user.name "${GITHUB_ACTOR}" && \
-          git config user.email "${GITHUB_ACTOR}@users.noreply.github.com" && \
-          git add . && \
-          git commit -m "[cron] Bump distribution date ($DIST)" && \
-          git push
-        fi
-        exit 0
@@ -1,34 +0,0 @@
-#
-# check-pr.yml
-# Close PRs directed at release branches
-#
-
-name: PR Bad Target
-
-on:
-  pull_request_target:
-    types: [opened]
-    branches:
-    - 1.0.x
-    - 1.1.x
-    - 2.0.x
-    - 2.1.x
-
-jobs:
-  bad_target:
-    name: PR Bad Target
-    if: github.repository == 'MarlinFirmware/Marlin'
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: superbrothers/close-pull-request@v3
-      with:
-        comment: >
-          Thanks for your contribution! Unfortunately we can't accept PRs directed at release branches. We make patches to the bugfix branches and only later do we push them out as releases.
-
-          Please redo this PR starting with the `bugfix-2.1.x` branch and be careful to target `bugfix-2.1.x` when resubmitting the PR. Patches may also target `bugfix-2.0.x` if they are specifically for 2.0.9.x.
-
-          It may help to set your fork's default branch to `bugfix-2.0.x`.
-
-          See [this page](https://marlinfw.org/docs/development/getting_started_pull_requests.html) for full instructions.
@@ -1,39 +0,0 @@
-#
-# clean-closed.yml
-# Remove obsolete labels when an Issue or PR is closed
-#
-
-name: Clean Closed
-
-on:
-  pull_request:
-    types: [closed]
-  issues:
-    types: [closed]
-
-jobs:
-  remove_label:
-    runs-on: ubuntu-latest
-
-    strategy:
-      matrix:
-        label:
-          - "S: Don't Merge"
-          - "S: Hold for 2.1"
-          - "S: Please Merge"
-          - "S: Please Test"
-          - "help wanted"
-          - "Needs: Discussion"
-          - "Needs: Documentation"
-          - "Needs: More Data"
-          - "Needs: Patch"
-          - "Needs: Testing"
-          - "Needs: Work"
-
-    steps:
-      - uses: actions/checkout@v2
-      - name: Remove Labels
-        uses: actions-ecosystem/action-remove-labels@v1
-        with:
-          github_token: ${{ github.token }}
-          labels: ${{ matrix.label }}
@@ -1,28 +0,0 @@
-#
-# close-stale.yml
-# Close open issues after a period of inactivity
-#
-
-name: Close Stale Issues
-
-on:
-  schedule:
-  - cron: "22 1 * * *"
-
-jobs:
-  stale:
-    name: Close Stale Issues
-    if: github.repository == 'MarlinFirmware/Marlin'
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/stale@v3
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        stale-issue-message: 'This issue has had no activity in the last 60 days. Please add a reply if you want to keep this issue active, otherwise it will be automatically closed within 10 days.'
-        days-before-stale: 60
-        days-before-close: 10
-        stale-issue-label: 'stale-closing-soon'
-        exempt-all-assignees: true
-        exempt-issue-labels: 'Bug: Confirmed !,T: Feature Request,Needs: More Data,Needs: Discussion,Needs: Documentation,Needs: Patch,Needs: Work,Needs: Testing,help wanted,no-locking'
@@ -1,32 +0,0 @@
-#
-# lock-closed.yml
-# Lock closed issues after a period of inactivity
-#
-
-name: Lock Closed Issues
-
-on:
-  schedule:
-    - cron: '0 1/13 * * *'
-
-jobs:
-  lock:
-    name: Lock Closed Issues
-    if: github.repository == 'MarlinFirmware/Marlin'
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: dessant/lock-threads@v2
-      with:
-        github-token: ${{ github.token }}
-        process-only: 'issues'
-        issue-lock-inactive-days: '60'
-        issue-exclude-created-before: ''
-        issue-exclude-labels: 'no-locking'
-        issue-lock-labels: ''
-        issue-lock-comment: >
-          This issue has been automatically locked since there
-          has not been any recent activity after it was closed.
-          Please open a new issue for related bugs.
-        issue-lock-reason: ''
@@ -8,7 +8,7 @@ name: CI
 on:
  pull_request:
    branches:
-    - bugfix-2.1.x
+    - bugfix-2.0.x
    paths-ignore:
    - config/**
    - data/**
@@ -16,7 +16,7 @@ on:
    - '**/*.md'
  push:
    branches:
-    - bugfix-2.1.x
+    - bugfix-2.0.x
    paths-ignore:
    - config/**
    - data/**
@@ -45,7 +45,6 @@ jobs:
        - teensy35
        - teensy41
        - SAMD51_grandcentral_m4
-        - PANDA_PI_V29

        # Extended AVR Environments

@@ -60,13 +59,13 @@ jobs:
        #- STM32F103RC_btt_maple
        - STM32F103RC_btt_USB_maple
        - STM32F103RC_fysetc_maple
-        - STM32F103RC_meeb_maple
+        - STM32F103RC_meeb
        - jgaurora_a5s_a1_maple
        - STM32F103VE_longer_maple
        #- mks_robin_maple
        - mks_robin_lite_maple
        - mks_robin_pro_maple
-        #- mks_robin_nano_v1v2_maple
+        #- mks_robin_nano35_maple
        #- STM32F103RE_creality_maple
        - STM32F103VE_ZM3E4V2_USB_maple

@@ -77,9 +76,9 @@ jobs:
        - STM32F103RE_btt
        - STM32F103RE_btt_USB
        - STM32F103RE_creality
-        - STM32F401RC_creality
        - STM32F103VE_longer
        - STM32F407VE_black
+        - STM32F401VE_STEVAL
        - BIGTREE_BTT002
        - BIGTREE_SKR_PRO
        - BIGTREE_GTR_V1_0
@@ -93,17 +92,12 @@ jobs:
        - rumba32
        - LERDGEX
        - LERDGEK
-        - mks_robin_nano_v1v2
-        #- mks_robin_nano_v1v2_usbmod
-        #- mks_robin_nano_v1_3_f4_usbmod
+        - mks_robin_nano35
        - NUCLEO_F767ZI
        - REMRAM_V1
        - BTT_SKR_SE_BX
        - chitu_f103
-        - Opulo_Lumen_REV3
-
-        # ESP32 environments
-        - mks_tinybee
+        - Index_Mobo_Rev03

        # Put lengthy tests last

@@ -143,9 +137,8 @@ jobs:

    - name: Install PlatformIO
      run: |
-        pip install -U platformio
-        pio upgrade --dev
-        pio pkg update --global
+        pip install -U https://github.com/platformio/platformio-core/archive/v5.2.5.zip
+        platformio update

    - name: Run ${{ matrix.test-platform }} Tests
      run: |
@@ -1,22 +0,0 @@
-#
-# unlock-reopened.yml
-# Unlock an issue whenever it is re-opened
-#
-
-name: "Unlock reopened issue"
-
-on:
-  issues:
-    types: [reopened]
-
-jobs:
-  unlock:
-    name: Unlock Reopened
-    if: github.repository == 'MarlinFirmware/Marlin'
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: OSDKDev/unlock-issues@v1.1
-      with:
-        repo-token: "${{ secrets.GITHUB_TOKEN }}"
@@ -147,7 +147,6 @@ vc-fileutils.settings
 imgui.ini
 eeprom.dat
 spi_flash.bin
-fs.img

 #cmake
 CMakeLists.txt
@@ -27,7 +27,7 @@ tests-single-ci:

 tests-single-local:
 	@if ! test -n "$(TEST_TARGET)" ; then echo "***ERROR*** Set TEST_TARGET=<your-module> or use make tests-all-local" ; return 1; fi
-	export PATH="./buildroot/bin/:./buildroot/tests/:${PATH}" \
+	export PATH=./buildroot/bin/:./buildroot/tests/:${PATH} \
 	  && export VERBOSE_PLATFORMIO=$(VERBOSE_PLATFORMIO) \
 	  && run_tests . $(TEST_TARGET) "$(ONLY_TEST)"
 .PHONY: tests-single-local
@@ -38,7 +38,7 @@ tests-single-local-docker:
 .PHONY: tests-single-local-docker

 tests-all-local:
-	export PATH="./buildroot/bin/:./buildroot/tests/:${PATH}" \
+	export PATH=./buildroot/bin/:./buildroot/tests/:${PATH} \
 	  && export VERBOSE_PLATFORMIO=$(VERBOSE_PLATFORMIO) \
 	  && for TEST_TARGET in $$(./get_test_targets.py) ; do echo "Running tests for $$TEST_TARGET" ; run_tests . $$TEST_TARGET ; done
 .PHONY: tests-all-local
@@ -109,7 +109,7 @@ LIQUID_TWI2        ?= 0
 # This defines if Wire is needed
 WIRE               ?= 0

-# This defines if Tone is needed (i.e., SPEAKER is defined in Configuration.h)
+# This defines if Tone is needed (i.e SPEAKER is defined in Configuration.h)
 # Disabling this (and SPEAKER) saves approximately 350 bytes of memory.
 TONE               ?= 1

@@ -307,22 +307,133 @@ else ifeq ($(HARDWARE_MOTHERBOARD),1154)
 else ifeq ($(HARDWARE_MOTHERBOARD),1155)
 # Tenlog D3 Hero IDEX printer
 else ifeq ($(HARDWARE_MOTHERBOARD),1156)
-# Tenlog D3,5,6 Pro IDEX printers
-else ifeq ($(HARDWARE_MOTHERBOARD),1157)
 # Ramps S 1.2 by Sakul.cz (Power outputs: Hotend0, Hotend1, Fan, Bed)
-else ifeq ($(HARDWARE_MOTHERBOARD),1158)
+else ifeq ($(HARDWARE_MOTHERBOARD),1157)
 # Ramps S 1.2 by Sakul.cz (Power outputs: Hotend0, Hotend1, Hotend2, Bed)
-else ifeq ($(HARDWARE_MOTHERBOARD),1159)
+else ifeq ($(HARDWARE_MOTHERBOARD),1158)
 # Ramps S 1.2 by Sakul.cz (Power outputs: Hotend, Fan0, Fan1, Bed)
-else ifeq ($(HARDWARE_MOTHERBOARD),1160)
+else ifeq ($(HARDWARE_MOTHERBOARD),1159)
 # Longer LK1 PRO / Alfawise U20 Pro (PRO version)
-else ifeq ($(HARDWARE_MOTHERBOARD),1161)
+else ifeq ($(HARDWARE_MOTHERBOARD),1160)
 # Longer LKx PRO / Alfawise Uxx Pro (PRO version)
-else ifeq ($(HARDWARE_MOTHERBOARD),1162)
-# Zonestar zrib V5.3 (Chinese RAMPS replica)
-else ifeq ($(HARDWARE_MOTHERBOARD),1163)
-# Pxmalion Core I3
-else ifeq ($(HARDWARE_MOTHERBOARD),1164)
+else ifeq ($(HARDWARE_MOTHERBOARD),1161)
+
+
+# 3Drag Controller
+else ifeq ($(HARDWARE_MOTHERBOARD),1100)
+# Velleman K8200 Controller (derived from 3Drag Controller)
+else ifeq ($(HARDWARE_MOTHERBOARD),1101)
+# Velleman K8400 Controller (derived from 3Drag Controller)
+else ifeq ($(HARDWARE_MOTHERBOARD),1102)
+# Velleman K8600 Controller (Vertex Nano)
+else ifeq ($(HARDWARE_MOTHERBOARD),1103)
+# Velleman K8800 Controller (Vertex Delta)
+else ifeq ($(HARDWARE_MOTHERBOARD),1104)
+# 2PrintBeta BAM&DICE with STK drivers
+else ifeq ($(HARDWARE_MOTHERBOARD),1105)
+# 2PrintBeta BAM&DICE Due with STK drivers
+else ifeq ($(HARDWARE_MOTHERBOARD),1106)
+# MKS BASE v1.0
+else ifeq ($(HARDWARE_MOTHERBOARD),1107)
+# MKS v1.4 with A4982 stepper drivers
+else ifeq ($(HARDWARE_MOTHERBOARD),1108)
+# MKS v1.5 with Allegro A4982 stepper drivers
+else ifeq ($(HARDWARE_MOTHERBOARD),1109)
+# MKS v1.6 with Allegro A4982 stepper drivers
+else ifeq ($(HARDWARE_MOTHERBOARD),1110)
+# MKS BASE 1.0 with Heroic HR4982 stepper drivers
+else ifeq ($(HARDWARE_MOTHERBOARD),1111)
+# MKS GEN v1.3 or 1.4
+else ifeq ($(HARDWARE_MOTHERBOARD),1112)
+# MKS GEN L
+else ifeq ($(HARDWARE_MOTHERBOARD),1113)
+# zrib V2.0 control board (Chinese RAMPS replica)
+else ifeq ($(HARDWARE_MOTHERBOARD),1114)
+# BigTreeTech or BIQU KFB2.0
+else ifeq ($(HARDWARE_MOTHERBOARD),1115)
+# Felix 2.0+ Electronics Board (RAMPS like)
+else ifeq ($(HARDWARE_MOTHERBOARD),1116)
+# Invent-A-Part RigidBoard
+else ifeq ($(HARDWARE_MOTHERBOARD),1117)
+# Invent-A-Part RigidBoard V2
+else ifeq ($(HARDWARE_MOTHERBOARD),1118)
+# Sainsmart 2-in-1 board
+else ifeq ($(HARDWARE_MOTHERBOARD),1119)
+# Ultimaker
+else ifeq ($(HARDWARE_MOTHERBOARD),1120)
+# Ultimaker (Older electronics. Pre 1.5.4. This is rare)
+else ifeq ($(HARDWARE_MOTHERBOARD),1121)
+  MCU              ?= atmega1280
+  PROG_MCU         ?= m1280
+
+# Azteeg X3
+else ifeq ($(HARDWARE_MOTHERBOARD),1122)
+# Azteeg X3 Pro
+else ifeq ($(HARDWARE_MOTHERBOARD),1123)
+# Ultimainboard 2.x (Uses TEMP_SENSOR 20)
+else ifeq ($(HARDWARE_MOTHERBOARD),1124)
+# Rumba
+else ifeq ($(HARDWARE_MOTHERBOARD),1125)
+# Raise3D Rumba
+else ifeq ($(HARDWARE_MOTHERBOARD),1126)
+# Rapide Lite RL200 Rumba
+else ifeq ($(HARDWARE_MOTHERBOARD),1127)
+# Formbot T-Rex 2 Plus
+else ifeq ($(HARDWARE_MOTHERBOARD),1128)
+# Formbot T-Rex 3
+else ifeq ($(HARDWARE_MOTHERBOARD),1129)
+# Formbot Raptor
+else ifeq ($(HARDWARE_MOTHERBOARD),1130)
+# Formbot Raptor 2
+else ifeq ($(HARDWARE_MOTHERBOARD),1131)
+# bq ZUM Mega 3D
+else ifeq ($(HARDWARE_MOTHERBOARD),1132)
+# MakeBoard Mini v2.1.2 is a control board sold by MicroMake
+else ifeq ($(HARDWARE_MOTHERBOARD),1133)
+# TriGorilla Anycubic version 1.3 based on RAMPS EFB
+else ifeq ($(HARDWARE_MOTHERBOARD),1134)
+# TriGorilla Anycubic version 1.4 based on RAMPS EFB
+else ifeq ($(HARDWARE_MOTHERBOARD),1135)
+# TriGorilla Anycubic version 1.4 Rev 1.1
+else ifeq ($(HARDWARE_MOTHERBOARD),1136)
+# Creality: Ender-4, CR-8
+else ifeq ($(HARDWARE_MOTHERBOARD),1137)
+# Creality: CR10S, CR20, CR-X
+else ifeq ($(HARDWARE_MOTHERBOARD),1138)
+# Dagoma F5
+else ifeq ($(HARDWARE_MOTHERBOARD),1139)
+# FYSETC F6 1.3
+else ifeq ($(HARDWARE_MOTHERBOARD),1140)
+# FYSETC F6 1.5
+else ifeq ($(HARDWARE_MOTHERBOARD),1141)
+# Duplicator i3 Plus
+else ifeq ($(HARDWARE_MOTHERBOARD),1142)
+# VORON
+else ifeq ($(HARDWARE_MOTHERBOARD),1143)
+# TRONXY V3 1.0
+else ifeq ($(HARDWARE_MOTHERBOARD),1144)
+# Z-Bolt X Series
+else ifeq ($(HARDWARE_MOTHERBOARD),1145)
+# TT OSCAR
+else ifeq ($(HARDWARE_MOTHERBOARD),1146)
+# Overlord/Overlord Pro
+else ifeq ($(HARDWARE_MOTHERBOARD),1147)
+# ADIMLab Gantry v1
+else ifeq ($(HARDWARE_MOTHERBOARD),1148)
+# ADIMLab Gantry v2
+else ifeq ($(HARDWARE_MOTHERBOARD),1149)
+# BIQU Tango V1
+else ifeq ($(HARDWARE_MOTHERBOARD),1150)
+# MKS GEN L V2
+else ifeq ($(HARDWARE_MOTHERBOARD),1151)
+# MKS GEN L V2.1
+else ifeq ($(HARDWARE_MOTHERBOARD),1152)
+# Copymaster 3D
+else ifeq ($(HARDWARE_MOTHERBOARD),1153)
+# Ortur 4
+else ifeq ($(HARDWARE_MOTHERBOARD),1154)
+# Tenlog D3 Hero
+else ifeq ($(HARDWARE_MOTHERBOARD),1155)

 #
 # RAMBo and derivatives
@@ -401,7 +512,7 @@ else ifeq ($(HARDWARE_MOTHERBOARD),1324)
 else ifeq ($(HARDWARE_MOTHERBOARD),1325)
 # Intamsys 4.0 (Funmat HT)
 else ifeq ($(HARDWARE_MOTHERBOARD),1326)
-# Malyan M180 Mainboard Version 2 (no display function, direct G-code only)
+# Malyan M180 Mainboard Version 2 (no display function, direct gcode only)
 else ifeq ($(HARDWARE_MOTHERBOARD),1327)
 # Geeetech GT2560 Rev B for A20(M/T/D)
 else ifeq ($(HARDWARE_MOTHERBOARD),1328)
@@ -28,7 +28,7 @@
 /**
 * Marlin release version identifier
 */
-//#define SHORT_BUILD_VERSION "bugfix-2.1.x"
+//#define SHORT_BUILD_VERSION "bugfix-2.0.x"

 /**
 * Verbose version identifier which should contain a reference to the location
@@ -41,7 +41,7 @@
 * here we define this default string as the date where the latest release
 * version was tagged.
 */
-//#define STRING_DISTRIBUTION_DATE "2022-12-05"
+//#define STRING_DISTRIBUTION_DATE "2022-04-05"

 /**
 * Defines a generic printer name to be output to the LCD after booting Marlin.
@@ -1,211 +0,0 @@
-#
-# Marlin Firmware
-# config.ini - Options to apply before the build
-#
-[config:base]
-ini_use_config                           = none
-
-# Load all config: sections in this file
-;ini_use_config                          = all
-# Load config file relative to Marlin/
-;ini_use_config                          = another.ini
-# Download configurations from GitHub
-;ini_use_config                          = example/Creality/Ender-5 Plus @ bugfix-2.1.x
-# Download configurations from your server
-;ini_use_config                          = https://me.myserver.com/path/to/configs
-# Evaluate config:base and do a config dump
-;ini_use_config                          = base
-;config_export                           = 2
-
-[config:minimal]
-motherboard                              = BOARD_RAMPS_14_EFB
-serial_port                              = 0
-baudrate                                 = 250000
-
-use_watchdog                             = on
-thermal_protection_hotends               = on
-thermal_protection_hysteresis            = 4
-thermal_protection_period                = 40
-
-bufsize                                  = 4
-block_buffer_size                        = 16
-max_cmd_size                             = 96
-
-extruders                                = 1
-temp_sensor_0                            = 1
-
-temp_hysteresis                          = 3
-heater_0_mintemp                         = 5
-heater_0_maxtemp                         = 275
-preheat_1_temp_hotend                    = 180
-
-bang_max                                 = 255
-pidtemp                                  = on
-pid_k1                                   = 0.95
-pid_max                                  = BANG_MAX
-pid_functional_range                     = 10
-
-default_kp                               = 22.20
-default_ki                               = 1.08
-default_kd                               = 114.00
-
-x_driver_type                            = A4988
-y_driver_type                            = A4988
-z_driver_type                            = A4988
-e0_driver_type                           = A4988
-
-x_bed_size                               = 200
-x_min_pos                                = 0
-x_max_pos                                = X_BED_SIZE
-
-y_bed_size                               = 200
-y_min_pos                                = 0
-y_max_pos                                = Y_BED_SIZE
-
-z_min_pos                                = 0
-z_max_pos                                = 200
-
-x_home_dir                               = -1
-y_home_dir                               = -1
-z_home_dir                               = -1
-
-use_xmin_plug                            = on
-use_ymin_plug                            = on
-use_zmin_plug                            = on
-
-x_min_endstop_inverting                  = false
-y_min_endstop_inverting                  = false
-z_min_endstop_inverting                  = false
-
-default_axis_steps_per_unit              = { 80, 80, 400, 500 }
-axis_relative_modes                      = { false, false, false, false }
-default_max_feedrate                     = { 300, 300, 5, 25 }
-default_max_acceleration                 = { 3000, 3000, 100, 10000 }
-
-homing_feedrate_mm_m                     = { (50*60), (50*60), (4*60) }
-homing_bump_divisor                      = { 2, 2, 4 }
-
-x_enable_on                              = 0
-y_enable_on                              = 0
-z_enable_on                              = 0
-e_enable_on                              = 0
-
-invert_x_dir                             = false
-invert_y_dir                             = true
-invert_z_dir                             = false
-invert_e0_dir                            = false
-
-invert_e_step_pin                        = false
-invert_x_step_pin                        = false
-invert_y_step_pin                        = false
-invert_z_step_pin                        = false
-
-disable_x                                = false
-disable_y                                = false
-disable_z                                = false
-disable_e                                = false
-
-proportional_font_ratio                  = 1.0
-default_nominal_filament_dia             = 1.75
-
-junction_deviation_mm                    = 0.013
-
-default_acceleration                     = 3000
-default_travel_acceleration              = 3000
-default_retract_acceleration             = 3000
-
-default_minimumfeedrate                  = 0.0
-default_mintravelfeedrate                = 0.0
-
-minimum_planner_speed                    = 0.05
-min_steps_per_segment                    = 6
-default_minsegmenttime                   = 20000
-
-[config:basic]
-bed_overshoot                            = 10
-busy_while_heating                       = on
-default_ejerk                            = 5.0
-default_keepalive_interval               = 2
-default_leveling_fade_height             = 0.0
-disable_inactive_extruder                = on
-display_charset_hd44780                  = JAPANESE
-eeprom_boot_silent                       = on
-eeprom_chitchat                          = on
-endstoppullups                           = on
-extrude_maxlength                        = 200
-extrude_mintemp                          = 170
-host_keepalive_feature                   = on
-hotend_overshoot                         = 15
-jd_handle_small_segments                 = on
-lcd_info_screen_style                    = 0
-lcd_language                             = en
-max_bed_power                            = 255
-mesh_inset                               = 0
-min_software_endstops                    = on
-max_software_endstops                    = on
-min_software_endstop_x                   = on
-min_software_endstop_y                   = on
-min_software_endstop_z                   = on
-max_software_endstop_x                   = on
-max_software_endstop_y                   = on
-max_software_endstop_z                   = on
-preheat_1_fan_speed                      = 0
-preheat_1_label                          = "PLA"
-preheat_1_temp_bed                       = 70
-prevent_cold_extrusion                   = on
-prevent_lengthy_extrude                  = on
-printjob_timer_autostart                 = on
-probing_margin                           = 10
-show_bootscreen                          = on
-soft_pwm_scale                           = 0
-string_config_h_author                   = "(none, default config)"
-temp_bed_hysteresis                      = 3
-temp_bed_residency_time                  = 10
-temp_bed_window                          = 1
-temp_residency_time                      = 10
-temp_window                              = 1
-validate_homing_endstops                 = on
-xy_probe_feedrate                        = (133*60)
-z_clearance_between_probes               = 5
-z_clearance_deploy_probe                 = 10
-z_clearance_multi_probe                  = 5
-
-[config:advanced]
-arc_support                              = on
-auto_report_temperatures                 = on
-autotemp                                 = on
-autotemp_oldweight                       = 0.98
-bed_check_interval                       = 5000
-default_stepper_deactive_time            = 120
-default_volumetric_extruder_limit        = 0.00
-disable_inactive_e                       = true
-disable_inactive_x                       = true
-disable_inactive_y                       = true
-disable_inactive_z                       = true
-e0_auto_fan_pin                          = -1
-encoder_100x_steps_per_sec               = 80
-encoder_10x_steps_per_sec                = 30
-encoder_rate_multiplier                  = on
-extended_capabilities_report             = on
-extruder_auto_fan_speed                  = 255
-extruder_auto_fan_temperature            = 50
-fanmux0_pin                              = -1
-fanmux1_pin                              = -1
-fanmux2_pin                              = -1
-faster_gcode_parser                      = on
-homing_bump_mm                           = { 5, 5, 2 }
-max_arc_segment_mm                       = 1.0
-min_arc_segment_mm                       = 0.1
-min_circle_segments                      = 72
-n_arc_correction                         = 25
-serial_overrun_protection                = on
-slowdown                                 = on
-slowdown_divisor                         = 2
-temp_sensor_bed                          = 0
-thermal_protection_bed_hysteresis        = 2
-thermocouple_max_errors                  = 15
-tx_buffer_size                           = 0
-watch_bed_temp_increase                  = 2
-watch_bed_temp_period                    = 60
-watch_temp_increase                      = 2
-watch_temp_period                        = 20
@@ -23,7 +23,6 @@

 #include "../../inc/MarlinConfig.h"
 #include "HAL.h"
-#include <avr/wdt.h>

 #ifdef USBCON
  DefaultSerial1 MSerial0(false, Serial);
@@ -89,62 +88,6 @@ void MarlinHAL::reboot() {
  #endif
 }

-// ------------------------
-// Watchdog Timer
-// ------------------------
-
-#if ENABLED(USE_WATCHDOG)
-
-  #include <avr/wdt.h>
-  #include "../../MarlinCore.h"
-
-  // Initialize watchdog with 8s timeout, if possible. Otherwise, make it 4s.
-  void MarlinHAL::watchdog_init() {
-    #if ENABLED(WATCHDOG_DURATION_8S) && defined(WDTO_8S)
-      #define WDTO_NS WDTO_8S
-    #else
-      #define WDTO_NS WDTO_4S
-    #endif
-    #if ENABLED(WATCHDOG_RESET_MANUAL)
-      // Enable the watchdog timer, but only for the interrupt.
-      // Take care, as this requires the correct order of operation, with interrupts disabled.
-      // See the datasheet of any AVR chip for details.
-      wdt_reset();
-      cli();
-      _WD_CONTROL_REG = _BV(_WD_CHANGE_BIT) | _BV(WDE);
-      _WD_CONTROL_REG = _BV(WDIE) | (WDTO_NS & 0x07) | ((WDTO_NS & 0x08) << 2); // WDTO_NS directly does not work. bit 0-2 are consecutive in the register but the highest value bit is at bit 5
-                                                                                // So worked for up to WDTO_2S
-      sei();
-      wdt_reset();
-    #else
-      wdt_enable(WDTO_NS); // The function handles the upper bit correct.
-    #endif
-    //delay(10000); // test it!
-  }
-
-  //===========================================================================
-  //=================================== ISR ===================================
-  //===========================================================================
-
-  // Watchdog timer interrupt, called if main program blocks >4sec and manual reset is enabled.
-  #if ENABLED(WATCHDOG_RESET_MANUAL)
-    ISR(WDT_vect) {
-      sei();  // With the interrupt driven serial we need to allow interrupts.
-      SERIAL_ERROR_MSG(STR_WATCHDOG_FIRED);
-      minkill();  // interrupt-safe final kill and infinite loop
-    }
-  #endif
-
-  // Reset watchdog. MUST be called at least every 4 seconds after the
-  // first watchdog_init or AVR will go into emergency procedures.
-  void MarlinHAL::watchdog_refresh() { wdt_reset(); }
-
-#endif // USE_WATCHDOG
-
-// ------------------------
-// Free Memory Accessor
-// ------------------------
-
 #if ENABLED(SDSUPPORT)

  #include "../../sd/SdFatUtil.h"
@@ -19,20 +19,17 @@
 */
 #pragma once

-/**
- * HAL for Arduino AVR
- */
-
 #include "../shared/Marduino.h"
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
+#include "watchdog.h"
 #include "math.h"

 #ifdef USBCON
  #include <HardwareSerial.h>
 #else
+  #define HardwareSerial_h // Hack to prevent HardwareSerial.h header inclusion
  #include "MarlinSerial.h"
-  #define BOARD_NO_NATIVE_USB
 #endif

 #include <stdint.h>
@@ -107,36 +104,36 @@ typedef Servo hal_servo_t;

  #define MYSERIAL1 TERN(BLUETOOTH, btSerial, MSerial0)
 #else
-  #if !WITHIN(SERIAL_PORT, 0, 3)
-    #error "SERIAL_PORT must be from 0 to 3."
+  #if !WITHIN(SERIAL_PORT, -1, 3)
+    #error "SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
  #endif
  #define MYSERIAL1 customizedSerial1

  #ifdef SERIAL_PORT_2
-    #if !WITHIN(SERIAL_PORT_2, 0, 3)
-      #error "SERIAL_PORT_2 must be from 0 to 3."
+    #if !WITHIN(SERIAL_PORT_2, -1, 3)
+      #error "SERIAL_PORT_2 must be from 0 to 3, or -1 for USB Serial."
    #endif
    #define MYSERIAL2 customizedSerial2
  #endif

  #ifdef SERIAL_PORT_3
-    #if !WITHIN(SERIAL_PORT_3, 0, 3)
-      #error "SERIAL_PORT_3 must be from 0 to 3."
+    #if !WITHIN(SERIAL_PORT_3, -1, 3)
+      #error "SERIAL_PORT_3 must be from 0 to 3, or -1 for USB Serial."
    #endif
    #define MYSERIAL3 customizedSerial3
  #endif
 #endif

 #ifdef MMU2_SERIAL_PORT
-  #if !WITHIN(MMU2_SERIAL_PORT, 0, 3)
-    #error "MMU2_SERIAL_PORT must be from 0 to 3"
+  #if !WITHIN(MMU2_SERIAL_PORT, -1, 3)
+    #error "MMU2_SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
  #endif
  #define MMU2_SERIAL mmuSerial
 #endif

 #ifdef LCD_SERIAL_PORT
-  #if !WITHIN(LCD_SERIAL_PORT, 0, 3)
-    #error "LCD_SERIAL_PORT must be from 0 to 3."
+  #if !WITHIN(LCD_SERIAL_PORT, -1, 3)
+    #error "LCD_SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
  #endif
  #define LCD_SERIAL lcdSerial
  #if HAS_DGUS_LCD
@@ -167,7 +164,7 @@ typedef Servo hal_servo_t;
 #define strtof strtod

 // ------------------------
-// Free Memory Accessor
+// Class Utilities
 // ------------------------

 #pragma GCC diagnostic push
@@ -189,10 +186,6 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  // Watchdog
-  static void watchdog_init()    IF_DISABLED(USE_WATCHDOG, {});
-  static void watchdog_refresh() IF_DISABLED(USE_WATCHDOG, {});
-
  static void init();          // Called early in setup()
  static void init_board() {}  // Called less early in setup()
  static void reboot();        // Restart the firmware from 0x0
@@ -66,26 +66,27 @@ static volatile int8_t Channel[_Nbr_16timers];              // counter for the s

 /************ static functions common to all instances ***********************/

-static inline void handle_interrupts(const timer16_Sequence_t timer, volatile uint16_t* TCNTn, volatile uint16_t* OCRnA) {
-  int8_t cho = Channel[timer];                                        // Handle the prior Channel[timer] first
-  if (cho < 0)                                                        // Channel -1 indicates the refresh interval completed...
-    *TCNTn = 0;                                                       // ...so reset the timer
-  else if (SERVO_INDEX(timer, cho) < ServoCount)                      // prior channel handled?
-    extDigitalWrite(SERVO(timer, cho).Pin.nbr, LOW);                  // pulse the prior channel LOW
+static inline void handle_interrupts(timer16_Sequence_t timer, volatile uint16_t* TCNTn, volatile uint16_t* OCRnA) {
+  if (Channel[timer] < 0)
+    *TCNTn = 0; // channel set to -1 indicated that refresh interval completed so reset the timer
+  else {
+    if (SERVO_INDEX(timer, Channel[timer]) < ServoCount && SERVO(timer, Channel[timer]).Pin.isActive)
+      extDigitalWrite(SERVO(timer, Channel[timer]).Pin.nbr, LOW); // pulse this channel low if activated
+  }

-  Channel[timer] = ++cho;                                             // Handle the next channel (or 0)
-  if (cho < SERVOS_PER_TIMER && SERVO_INDEX(timer, cho) < ServoCount) {
-    *OCRnA = *TCNTn + SERVO(timer, cho).ticks;                        // set compare to current ticks plus duration
-    if (SERVO(timer, cho).Pin.isActive)                               // activated?
-      extDigitalWrite(SERVO(timer, cho).Pin.nbr, HIGH);               // yes: pulse HIGH
+  Channel[timer]++;    // increment to the next channel
+  if (SERVO_INDEX(timer, Channel[timer]) < ServoCount && Channel[timer] < SERVOS_PER_TIMER) {
+    *OCRnA = *TCNTn + SERVO(timer, Channel[timer]).ticks;
+    if (SERVO(timer, Channel[timer]).Pin.isActive)    // check if activated
+      extDigitalWrite(SERVO(timer, Channel[timer]).Pin.nbr, HIGH); // it's an active channel so pulse it high
  }
  else {
    // finished all channels so wait for the refresh period to expire before starting over
-    const unsigned int cval = ((unsigned)*TCNTn) + 32 / (SERVO_TIMER_PRESCALER), // allow 32 cycles to ensure the next OCR1A not missed
-                       ival = (unsigned int)usToTicks(REFRESH_INTERVAL); // at least REFRESH_INTERVAL has elapsed
-    *OCRnA = max(cval, ival);
-
-    Channel[timer] = -1;                                              // reset the timer counter to 0 on the next call
+    if (((unsigned)*TCNTn) + 4 < usToTicks(REFRESH_INTERVAL))    // allow a few ticks to ensure the next OCR1A not missed
+      *OCRnA = (unsigned int)usToTicks(REFRESH_INTERVAL);
+    else
+      *OCRnA = *TCNTn + 4;  // at least REFRESH_INTERVAL has elapsed
+    Channel[timer] = -1; // this will get incremented at the end of the refresh period to start again at the first channel
  }
 }

@@ -122,102 +123,91 @@ static inline void handle_interrupts(const timer16_Sequence_t timer, volatile ui

 /****************** end of static functions ******************************/

-void initISR(const timer16_Sequence_t timer_index) {
-  switch (timer_index) {
-    default: break;
+void initISR(timer16_Sequence_t timer) {
+  #ifdef _useTimer1
+    if (timer == _timer1) {
+      TCCR1A = 0;             // normal counting mode
+      TCCR1B = _BV(CS11);     // set prescaler of 8
+      TCNT1 = 0;              // clear the timer count
+      #if defined(__AVR_ATmega8__) || defined(__AVR_ATmega128__)
+        SBI(TIFR, OCF1A);      // clear any pending interrupts;
+        SBI(TIMSK, OCIE1A);    // enable the output compare interrupt
+      #else
+        // here if not ATmega8 or ATmega128
+        SBI(TIFR1, OCF1A);     // clear any pending interrupts;
+        SBI(TIMSK1, OCIE1A);   // enable the output compare interrupt
+      #endif
+      #ifdef WIRING
+        timerAttach(TIMER1OUTCOMPAREA_INT, Timer1Service);
+      #endif
+    }
+  #endif

-    #ifdef _useTimer1
-      case _timer1:
-        TCCR1A = 0;             // normal counting mode
-        TCCR1B = _BV(CS11);     // set prescaler of 8
-        TCNT1 = 0;              // clear the timer count
-        #if defined(__AVR_ATmega8__) || defined(__AVR_ATmega128__)
-          SBI(TIFR, OCF1A);      // clear any pending interrupts;
-          SBI(TIMSK, OCIE1A);    // enable the output compare interrupt
-        #else
-          // here if not ATmega8 or ATmega128
-          SBI(TIFR1, OCF1A);     // clear any pending interrupts;
-          SBI(TIMSK1, OCIE1A);   // enable the output compare interrupt
-        #endif
-        #ifdef WIRING
-          timerAttach(TIMER1OUTCOMPAREA_INT, Timer1Service);
-        #endif
-        break;
-    #endif
+  #ifdef _useTimer3
+    if (timer == _timer3) {
+      TCCR3A = 0;             // normal counting mode
+      TCCR3B = _BV(CS31);     // set prescaler of 8
+      TCNT3 = 0;              // clear the timer count
+      #ifdef __AVR_ATmega128__
+        SBI(TIFR, OCF3A);     // clear any pending interrupts;
+        SBI(ETIMSK, OCIE3A);  // enable the output compare interrupt
+      #else
+        SBI(TIFR3, OCF3A);   // clear any pending interrupts;
+        SBI(TIMSK3, OCIE3A); // enable the output compare interrupt
+      #endif
+      #ifdef WIRING
+        timerAttach(TIMER3OUTCOMPAREA_INT, Timer3Service);  // for Wiring platform only
+      #endif
+    }
+  #endif

-    #ifdef _useTimer3
-      case _timer3:
-        TCCR3A = 0;             // normal counting mode
-        TCCR3B = _BV(CS31);     // set prescaler of 8
-        TCNT3 = 0;              // clear the timer count
-        #ifdef __AVR_ATmega128__
-          SBI(TIFR, OCF3A);     // clear any pending interrupts;
-          SBI(ETIMSK, OCIE3A);  // enable the output compare interrupt
-        #else
-          SBI(TIFR3, OCF3A);   // clear any pending interrupts;
-          SBI(TIMSK3, OCIE3A); // enable the output compare interrupt
-        #endif
-        #ifdef WIRING
-          timerAttach(TIMER3OUTCOMPAREA_INT, Timer3Service);  // for Wiring platform only
-        #endif
-        break;
-    #endif
+  #ifdef _useTimer4
+    if (timer == _timer4) {
+      TCCR4A = 0;             // normal counting mode
+      TCCR4B = _BV(CS41);     // set prescaler of 8
+      TCNT4 = 0;              // clear the timer count
+      TIFR4 = _BV(OCF4A);     // clear any pending interrupts;
+      TIMSK4 = _BV(OCIE4A);   // enable the output compare interrupt
+    }
+  #endif

-    #ifdef _useTimer4
-      case _timer4:
-        TCCR4A = 0;             // normal counting mode
-        TCCR4B = _BV(CS41);     // set prescaler of 8
-        TCNT4 = 0;              // clear the timer count
-        TIFR4 = _BV(OCF4A);     // clear any pending interrupts;
-        TIMSK4 = _BV(OCIE4A);   // enable the output compare interrupt
-        break;
-    #endif
-
-    #ifdef _useTimer5
-      case _timer5:
-        TCCR5A = 0;             // normal counting mode
-        TCCR5B = _BV(CS51);     // set prescaler of 8
-        TCNT5 = 0;              // clear the timer count
-        TIFR5 = _BV(OCF5A);     // clear any pending interrupts;
-        TIMSK5 = _BV(OCIE5A);   // enable the output compare interrupt
-        break;
-    #endif
-  }
+  #ifdef _useTimer5
+    if (timer == _timer5) {
+      TCCR5A = 0;             // normal counting mode
+      TCCR5B = _BV(CS51);     // set prescaler of 8
+      TCNT5 = 0;              // clear the timer count
+      TIFR5 = _BV(OCF5A);     // clear any pending interrupts;
+      TIMSK5 = _BV(OCIE5A);   // enable the output compare interrupt
+    }
+  #endif
 }

-void finISR(const timer16_Sequence_t timer_index) {
+void finISR(timer16_Sequence_t timer) {
  // Disable use of the given timer
  #ifdef WIRING
-    switch (timer_index) {
-      default: break;
-
-      case _timer1:
-        CBI(
-          #if defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2561__)
-            TIMSK1
-          #else
-            TIMSK
-          #endif
-          , OCIE1A    // disable timer 1 output compare interrupt
-        );
-        timerDetach(TIMER1OUTCOMPAREA_INT);
-        break;
-
-      case _timer3:
-        CBI(
-          #if defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2561__)
-            TIMSK3
-          #else
-            ETIMSK
-          #endif
-          , OCIE3A    // disable the timer3 output compare A interrupt
-        );
-        timerDetach(TIMER3OUTCOMPAREA_INT);
-        break;
+    if (timer == _timer1) {
+      CBI(
+        #if defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2561__)
+          TIMSK1
+        #else
+          TIMSK
+        #endif
+          , OCIE1A);    // disable timer 1 output compare interrupt
+      timerDetach(TIMER1OUTCOMPAREA_INT);
+    }
+    else if (timer == _timer3) {
+      CBI(
+        #if defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2561__)
+          TIMSK3
+        #else
+          ETIMSK
+        #endif
+          , OCIE3A);    // disable the timer3 output compare A interrupt
+      timerDetach(TIMER3OUTCOMPAREA_INT);
    }
  #else // !WIRING
    // For arduino - in future: call here to a currently undefined function to reset the timer
-    UNUSED(timer_index);
+    UNUSED(timer);
  #endif
 }

@@ -146,10 +146,10 @@ void MarlinHAL::set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
      LIMIT(res_pc_temp, 1U, maxtop);

      // Calculate frequencies of test prescaler and resolution values
-      const uint16_t f_fast_temp = (F_CPU) / (p * (1 + res_fast_temp)),
-                     f_pc_temp   = (F_CPU) / (2 * p * res_pc_temp);
-      const int      f_diff      = _MAX(f, f_desired) - _MIN(f, f_desired),
+      const uint32_t f_diff      = _MAX(f, f_desired) - _MIN(f, f_desired),
+                     f_fast_temp = (F_CPU) / (p * (1 + res_fast_temp)),
                     f_fast_diff = _MAX(f_fast_temp, f_desired) - _MIN(f_fast_temp, f_desired),
+                     f_pc_temp   = (F_CPU) / (2 * p * res_pc_temp),
                     f_pc_diff   = _MAX(f_pc_temp, f_desired) - _MIN(f_pc_temp, f_desired);

      if (f_fast_diff < f_diff && f_fast_diff <= f_pc_diff) { // FAST values are closest to desired f
@@ -293,11 +293,11 @@ enum ClockSource2 : uint8_t {

 #if HAS_MOTOR_CURRENT_PWM
  #if PIN_EXISTS(MOTOR_CURRENT_PWM_XY)
-    #define PWM_CHK_MOTOR_CURRENT(P) (P == MOTOR_CURRENT_PWM_E || P == MOTOR_CURRENT_PWM_E0  || P == MOTOR_CURRENT_PWM_E1 || P == MOTOR_CURRENT_PWM_Z || P == MOTOR_CURRENT_PWM_XY)
+    #define PWM_CHK_MOTOR_CURRENT(P) (P == MOTOR_CURRENT_PWM_E || P == MOTOR_CURRENT_PWM_Z || P == MOTOR_CURRENT_PWM_XY)
  #elif PIN_EXISTS(MOTOR_CURRENT_PWM_Z)
-    #define PWM_CHK_MOTOR_CURRENT(P) (P == MOTOR_CURRENT_PWM_E || P == MOTOR_CURRENT_PWM_E0  || P == MOTOR_CURRENT_PWM_E1 || P == MOTOR_CURRENT_PWM_Z)
+    #define PWM_CHK_MOTOR_CURRENT(P) (P == MOTOR_CURRENT_PWM_E || P == MOTOR_CURRENT_PWM_Z)
  #else
-    #define PWM_CHK_MOTOR_CURRENT(P) (P == MOTOR_CURRENT_PWM_E || P == MOTOR_CURRENT_PWM_E0  || P == MOTOR_CURRENT_PWM_E1)
+    #define PWM_CHK_MOTOR_CURRENT(P) (P == MOTOR_CURRENT_PWM_E)
  #endif
 #else
  #define PWM_CHK_MOTOR_CURRENT(P) false
@@ -25,40 +25,6 @@
 * Test AVR-specific configuration values for errors at compile-time.
 */

-/**
- * Check for common serial pin conflicts
- */
-#define CHECK_SERIAL_PIN(N) ( \
-     X_STOP_PIN == N || Y_STOP_PIN == N || Z_STOP_PIN == N \
-  || X_MIN_PIN  == N || Y_MIN_PIN  == N || Z_MIN_PIN  == N \
-  || X_MAX_PIN  == N || Y_MAX_PIN  == N || Z_MAX_PIN  == N \
-  || X_STEP_PIN == N || Y_STEP_PIN == N || Z_STEP_PIN == N \
-  || X_DIR_PIN  == N || Y_DIR_PIN  == N || Z_DIR_PIN  == N \
-  || X_ENA_PIN  == N || Y_ENA_PIN  == N || Z_ENA_PIN  == N \
-  || BTN_EN1    == N || BTN_EN2    == N \
-)
-#if SERIAL_IN_USE(0)
-  // D0-D1. No known conflicts.
-#endif
-#if SERIAL_IN_USE(1)
-  #if NOT_TARGET(__AVR_ATmega644P__, __AVR_ATmega1284P__)
-    #if CHECK_SERIAL_PIN(18) || CHECK_SERIAL_PIN(19)
-      #error "Serial Port 1 pin D18 and/or D19 conflicts with another pin on the board."
-    #endif
-  #else
-    #if CHECK_SERIAL_PIN(10) || CHECK_SERIAL_PIN(11)
-      #error "Serial Port 1 pin D10 and/or D11 conflicts with another pin on the board."
-    #endif
-  #endif
-#endif
-#if SERIAL_IN_USE(2) && (CHECK_SERIAL_PIN(16) || CHECK_SERIAL_PIN(17))
-  #error "Serial Port 2 pin D16 and/or D17 conflicts with another pin on the board."
-#endif
-#if SERIAL_IN_USE(3) && (CHECK_SERIAL_PIN(14) || CHECK_SERIAL_PIN(15))
-  #error "Serial Port 3 pin D14 and/or D15 conflicts with another pin on the board."
-#endif
-#undef CHECK_SERIAL_PIN
-
 /**
 * Checks for FAST PWM
 */
@@ -74,7 +74,7 @@
 #define MULTI_NAME_PAD 26 // space needed to be pretty if not first name assigned to a pin

 void PRINT_ARRAY_NAME(uint8_t x) {
-  PGM_P const name_mem_pointer = (PGM_P)pgm_read_ptr(&pin_array[x].name);
+  char *name_mem_pointer = (PGM_P)pgm_read_ptr(&pin_array[x].name);
  LOOP_L_N(y, MAX_NAME_LENGTH) {
    char temp_char = pgm_read_byte(name_mem_pointer + y);
    if (temp_char != 0)
@@ -0,0 +1,70 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef __AVR__
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(USE_WATCHDOG)
+
+#include "watchdog.h"
+
+#include "../../MarlinCore.h"
+
+// Initialize watchdog with 8s timeout, if possible. Otherwise, make it 4s.
+void watchdog_init() {
+  #if ENABLED(WATCHDOG_DURATION_8S) && defined(WDTO_8S)
+    #define WDTO_NS WDTO_8S
+  #else
+    #define WDTO_NS WDTO_4S
+  #endif
+  #if ENABLED(WATCHDOG_RESET_MANUAL)
+    // Enable the watchdog timer, but only for the interrupt.
+    // Take care, as this requires the correct order of operation, with interrupts disabled.
+    // See the datasheet of any AVR chip for details.
+    wdt_reset();
+    cli();
+    _WD_CONTROL_REG = _BV(_WD_CHANGE_BIT) | _BV(WDE);
+    _WD_CONTROL_REG = _BV(WDIE) | (WDTO_NS & 0x07) | ((WDTO_NS & 0x08) << 2); // WDTO_NS directly does not work. bit 0-2 are consecutive in the register but the highest value bit is at bit 5
+                                                                              // So worked for up to WDTO_2S
+    sei();
+    wdt_reset();
+  #else
+    wdt_enable(WDTO_NS); // The function handles the upper bit correct.
+  #endif
+  //delay(10000); // test it!
+}
+
+//===========================================================================
+//=================================== ISR ===================================
+//===========================================================================
+
+// Watchdog timer interrupt, called if main program blocks >4sec and manual reset is enabled.
+#if ENABLED(WATCHDOG_RESET_MANUAL)
+  ISR(WDT_vect) {
+    sei();  // With the interrupt driven serial we need to allow interrupts.
+    SERIAL_ERROR_MSG(STR_WATCHDOG_FIRED);
+    minkill();  // interrupt-safe final kill and infinite loop
+  }
+#endif
+
+#endif // USE_WATCHDOG
+#endif // __AVR__
@@ -1,6 +1,6 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2022 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
@@ -21,16 +21,11 @@
 */
 #pragma once

-#include <stdint.h>
+#include <avr/wdt.h>

-class BDS_Leveling {
-public:
-  static int8_t config_state;
-  static uint8_t homing;
-  static void echo_name();
-  static void init(uint8_t _sda, uint8_t _scl, uint16_t delay_s);
-  static void process();
-  static float read();
-};
+// Initialize watchdog with a 4 second interrupt time
+void watchdog_init();

-extern BDS_Leveling bdl;
+// Reset watchdog. MUST be called at least every 4 seconds after the
+// first watchdog_init or AVR will go into emergency procedures.
+inline void HAL_watchdog_refresh() { wdt_reset(); }
@@ -25,7 +25,7 @@
 #ifdef ARDUINO_ARCH_SAM

 #include "../../inc/MarlinConfig.h"
-#include "../../MarlinCore.h"
+#include "HAL.h"

 #include <Wire.h>
 #include "usb/usb_task.h"
@@ -40,15 +40,14 @@ uint16_t MarlinHAL::adc_result;
 // Public functions
 // ------------------------

-#if ENABLED(POSTMORTEM_DEBUGGING)
-  extern void install_min_serial();
-#endif
+TERN_(POSTMORTEM_DEBUGGING, extern void install_min_serial());

 void MarlinHAL::init() {
+  // Initialize the USB stack
  #if ENABLED(SDSUPPORT)
    OUT_WRITE(SDSS, HIGH);  // Try to set SDSS inactive before any other SPI users start up
  #endif
-  usb_task_init();          // Initialize the USB stack
+  usb_task_init();
  TERN_(POSTMORTEM_DEBUGGING, install_min_serial()); // Install the min serial handler
 }

@@ -73,103 +72,6 @@ uint8_t MarlinHAL::get_reset_source() {

 void MarlinHAL::reboot() { rstc_start_software_reset(RSTC); }

-// ------------------------
-// Watchdog Timer
-// ------------------------
-
-#if ENABLED(USE_WATCHDOG)
-
-  // Initialize watchdog - On SAM3X, Watchdog was already configured
-  //  and enabled or disabled at startup, so no need to reconfigure it
-  //  here.
-  void MarlinHAL::watchdog_init() { WDT_Restart(WDT); } // Reset watchdog to start clean
-
-  // Reset watchdog. MUST be called at least every 4 seconds after the
-  // first watchdog_init or AVR will go into emergency procedures.
-  void MarlinHAL::watchdog_refresh() { watchdogReset(); }
-
-#endif
-
-// Override Arduino runtime to either config or disable the watchdog
-//
-// We need to configure the watchdog as soon as possible in the boot
-// process, because watchdog initialization at hardware reset on SAM3X8E
-// is unreliable, and there is risk of unintended resets if we delay
-// that initialization to a later time.
-void watchdogSetup() {
-
-  #if ENABLED(USE_WATCHDOG)
-
-    // 4 seconds timeout
-    uint32_t timeout = TERN(WATCHDOG_DURATION_8S, 8000, 4000);
-
-    // Calculate timeout value in WDT counter ticks: This assumes
-    // the slow clock is running at 32.768 kHz watchdog
-    // frequency is therefore 32768 / 128 = 256 Hz
-    timeout = (timeout << 8) / 1000;
-    if (timeout == 0)
-      timeout = 1;
-    else if (timeout > 0xFFF)
-      timeout = 0xFFF;
-
-    // We want to enable the watchdog with the specified timeout
-    uint32_t value =
-      WDT_MR_WDV(timeout) |               // With the specified timeout
-      WDT_MR_WDD(timeout) |               // and no invalid write window
-    #if !(SAMV70 || SAMV71 || SAME70 || SAMS70)
-      WDT_MR_WDRPROC   |                  // WDT fault resets processor only - We want
-                                          // to keep PIO controller state
-    #endif
-      WDT_MR_WDDBGHLT  |                  // WDT stops in debug state.
-      WDT_MR_WDIDLEHLT;                   // WDT stops in idle state.
-
-    #if ENABLED(WATCHDOG_RESET_MANUAL)
-      // We enable the watchdog timer, but only for the interrupt.
-
-      // Configure WDT to only trigger an interrupt
-      value |= WDT_MR_WDFIEN;             // Enable WDT fault interrupt.
-
-      // Disable WDT interrupt (just in case, to avoid triggering it!)
-      NVIC_DisableIRQ(WDT_IRQn);
-
-      // We NEED memory barriers to ensure Interrupts are actually disabled!
-      // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
-      __DSB();
-      __ISB();
-
-      // Initialize WDT with the given parameters
-      WDT_Enable(WDT, value);
-
-      // Configure and enable WDT interrupt.
-      NVIC_ClearPendingIRQ(WDT_IRQn);
-      NVIC_SetPriority(WDT_IRQn, 0); // Use highest priority, so we detect all kinds of lockups
-      NVIC_EnableIRQ(WDT_IRQn);
-
-    #else
-
-      // a WDT fault triggers a reset
-      value |= WDT_MR_WDRSTEN;
-
-      // Initialize WDT with the given parameters
-      WDT_Enable(WDT, value);
-
-    #endif
-
-    // Reset the watchdog
-    WDT_Restart(WDT);
-
-  #else
-
-    // Make sure to completely disable the Watchdog
-    WDT_Disable(WDT);
-
-  #endif
-}
-
-// ------------------------
-// Free Memory Accessor
-// ------------------------
-
 extern "C" {
  extern unsigned int _ebss; // end of bss section
 }
@@ -180,10 +82,6 @@ int freeMemory() {
  return (int)&free_memory - (heap_end ?: (int)&_ebss);
 }

-// ------------------------
-// Serial Ports
-// ------------------------
-
 // Forward the default serial ports
 #if USING_HW_SERIAL0
  DefaultSerial1 MSerial0(false, Serial);
@@ -32,6 +32,7 @@
 #include "../shared/math_32bit.h"
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
+#include "watchdog.h"

 #include <stdint.h>

@@ -114,8 +115,8 @@ typedef Servo hal_servo_t;
 //
 // Interrupts
 //
-#define sei() interrupts()
-#define cli() noInterrupts()
+#define sei() noInterrupts()
+#define cli() interrupts()

 #define CRITICAL_SECTION_START()  const bool _irqon = hal.isr_state(); hal.isr_off()
 #define CRITICAL_SECTION_END()    if (_irqon) hal.isr_on()
@@ -175,13 +176,9 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  // Watchdog
-  static void watchdog_init()    IF_DISABLED(USE_WATCHDOG, {});
-  static void watchdog_refresh() IF_DISABLED(USE_WATCHDOG, {});
-
-  static void init();          // Called early in setup()
-  static void init_board();    // Called less early in setup()
-  static void reboot();        // Restart the firmware
+  static void init();       // Called early in setup()
+  static void init_board(); // Called less early in setup()
+  static void reboot();     // Software reset

  // Interrupts
  static bool isr_state() { return !__get_PRIMASK(); }
@@ -210,7 +207,7 @@ public:
  static void adc_init() {}

  // Called by Temperature::init for each sensor at startup
-  static void adc_enable(const uint8_t /*ch*/) {}
+  static void adc_enable(const uint8_t ch) {}

  // Begin ADC sampling on the given channel. Called from Temperature::isr!
  static void adc_start(const uint8_t ch) { adc_result = analogRead(ch); }
@@ -25,7 +25,7 @@

 #if ENABLED(POSTMORTEM_DEBUGGING)

-#include "../shared/MinSerial.h"
+#include "../shared/HAL_MinSerial.h"

 #include <stdarg.h>

@@ -31,6 +31,8 @@

 /**
 * HAL for Arduino Due and compatible (SAM3X8E)
+ *
+ * For ARDUINO_ARCH_SAM
 */

 #ifdef ARDUINO_ARCH_SAM
@@ -247,12 +249,12 @@
      b <<= 1; // little setup time

      WRITE(SD_SCK_PIN, HIGH);
-      DELAY_NS_VAR(spiDelayNS);
+      DELAY_NS(spiDelayNS);

      b |= (READ(SD_MISO_PIN) != 0);

      WRITE(SD_SCK_PIN, LOW);
-      DELAY_NS_VAR(spiDelayNS);
+      DELAY_NS(spiDelayNS);
    } while (--bits);
    return b;
  }
@@ -41,7 +41,7 @@
   practice, we need alignment to 256 bytes to make this work in all
   cases */
 __attribute__ ((aligned(256)))
-static DeviceVectors ram_tab[61] = { nullptr };
+static DeviceVectors ram_tab = { nullptr };

 /**
 * This function checks if the exception/interrupt table is already in SRAM or not.
@@ -47,12 +47,12 @@
 #include "../shared/servo.h"
 #include "../shared/servo_private.h"

-static Flags<_Nbr_16timers> DisablePending; // ISR should disable the timer at the next timer reset
+static volatile int8_t Channel[_Nbr_16timers];              // counter for the servo being pulsed for each timer (or -1 if refresh interval)

 // ------------------------
 /// Interrupt handler for the TC0 channel 1.
 // ------------------------
-void Servo_Handler(const timer16_Sequence_t, Tc*, const uint8_t);
+void Servo_Handler(timer16_Sequence_t timer, Tc *pTc, uint8_t channel);

 #ifdef _useTimer1
  void HANDLER_FOR_TIMER1() { Servo_Handler(_timer1, TC_FOR_TIMER1, CHANNEL_FOR_TIMER1); }
@@ -70,92 +70,88 @@ void Servo_Handler(const timer16_Sequence_t, Tc*, const uint8_t);
  void HANDLER_FOR_TIMER5() { Servo_Handler(_timer5, TC_FOR_TIMER5, CHANNEL_FOR_TIMER5); }
 #endif

-void Servo_Handler(const timer16_Sequence_t timer, Tc *tc, const uint8_t channel) {
-  static int8_t Channel[_Nbr_16timers];                               // Servo counters to pulse (or -1 for refresh interval)
-  int8_t cho = Channel[timer];                                        // Handle the prior Channel[timer] first
-  if (cho < 0) {                                                      // Channel -1 indicates the refresh interval completed...
-    tc->TC_CHANNEL[channel].TC_CCR |= TC_CCR_SWTRG;                   // ...so reset the timer
-    if (DisablePending[timer]) {
-      // Disabling only after the full servo period expires prevents
-      // pulses being too close together if immediately re-enabled.
-      DisablePending.clear(timer);
-      TC_Stop(tc, channel);
-      tc->TC_CHANNEL[channel].TC_SR;                                  // clear interrupt
-      return;
-    }
-  }
-  else if (SERVO_INDEX(timer, cho) < ServoCount)                      // prior channel handled?
-    extDigitalWrite(SERVO(timer, cho).Pin.nbr, LOW);                  // pulse the prior channel LOW
+void Servo_Handler(timer16_Sequence_t timer, Tc *tc, uint8_t channel) {
+  // clear interrupt
+  tc->TC_CHANNEL[channel].TC_SR;
+  if (Channel[timer] < 0)
+    tc->TC_CHANNEL[channel].TC_CCR |= TC_CCR_SWTRG; // channel set to -1 indicated that refresh interval completed so reset the timer
+  else if (SERVO_INDEX(timer, Channel[timer]) < ServoCount && SERVO(timer, Channel[timer]).Pin.isActive)
+    extDigitalWrite(SERVO(timer, Channel[timer]).Pin.nbr, LOW); // pulse this channel low if activated

-  Channel[timer] = ++cho;                                             // go to the next channel (or 0)
-  if (cho < SERVOS_PER_TIMER && SERVO_INDEX(timer, cho) < ServoCount) {
-    tc->TC_CHANNEL[channel].TC_RA = tc->TC_CHANNEL[channel].TC_CV + SERVO(timer, cho).ticks;
-    if (SERVO(timer, cho).Pin.isActive)                               // activated?
-      extDigitalWrite(SERVO(timer, cho).Pin.nbr, HIGH);               // yes: pulse HIGH
+  Channel[timer]++;    // increment to the next channel
+  if (SERVO_INDEX(timer, Channel[timer]) < ServoCount && Channel[timer] < SERVOS_PER_TIMER) {
+    tc->TC_CHANNEL[channel].TC_RA = tc->TC_CHANNEL[channel].TC_CV + SERVO(timer,Channel[timer]).ticks;
+    if (SERVO(timer,Channel[timer]).Pin.isActive)    // check if activated
+      extDigitalWrite(SERVO(timer, Channel[timer]).Pin.nbr, HIGH); // its an active channel so pulse it high
  }
  else {
    // finished all channels so wait for the refresh period to expire before starting over
-    const unsigned int cval = tc->TC_CHANNEL[channel].TC_CV + 128 / (SERVO_TIMER_PRESCALER), // allow 128 cycles to ensure the next CV not missed
-                       ival = (unsigned int)usToTicks(REFRESH_INTERVAL); // at least REFRESH_INTERVAL has elapsed
-    tc->TC_CHANNEL[channel].TC_RA = max(cval, ival);
-
-    Channel[timer] = -1;                                              // reset the timer CCR on the next call
+    tc->TC_CHANNEL[channel].TC_RA =
+      tc->TC_CHANNEL[channel].TC_CV < usToTicks(REFRESH_INTERVAL) - 4
+        ? (unsigned int)usToTicks(REFRESH_INTERVAL) // allow a few ticks to ensure the next OCR1A not missed
+        : tc->TC_CHANNEL[channel].TC_CV + 4;        // at least REFRESH_INTERVAL has elapsed
+    Channel[timer] = -1; // this will get incremented at the end of the refresh period to start again at the first channel
  }
-
-  tc->TC_CHANNEL[channel].TC_SR;                                      // clear interrupt
 }

 static void _initISR(Tc *tc, uint32_t channel, uint32_t id, IRQn_Type irqn) {
  pmc_enable_periph_clk(id);
  TC_Configure(tc, channel,
-      TC_CMR_WAVE                   // Waveform mode
-    | TC_CMR_WAVSEL_UP_RC           // Counter running up and reset when equal to RC
-    | (SERVO_TIMER_PRESCALER ==   2 ? TC_CMR_TCCLKS_TIMER_CLOCK1 : 0) // MCK/2
-    | (SERVO_TIMER_PRESCALER ==   8 ? TC_CMR_TCCLKS_TIMER_CLOCK2 : 0) // MCK/8
-    | (SERVO_TIMER_PRESCALER ==  32 ? TC_CMR_TCCLKS_TIMER_CLOCK3 : 0) // MCK/32
-    | (SERVO_TIMER_PRESCALER == 128 ? TC_CMR_TCCLKS_TIMER_CLOCK4 : 0) // MCK/128
-  );
+    TC_CMR_TCCLKS_TIMER_CLOCK3 | // MCK/32
+    TC_CMR_WAVE |                // Waveform mode
+    TC_CMR_WAVSEL_UP_RC );       // Counter running up and reset when equals to RC

-  // Wait 1ms before the first ISR
-  TC_SetRA(tc, channel, (F_CPU) / (SERVO_TIMER_PRESCALER) / 1000UL); // 1ms
+  /* 84MHz, MCK/32, for 1.5ms: 3937 */
+  TC_SetRA(tc, channel, 2625); // 1ms

-  // Configure and enable interrupt
+  /* Configure and enable interrupt */
  NVIC_EnableIRQ(irqn);
-  tc->TC_CHANNEL[channel].TC_IER = TC_IER_CPAS; // TC_IER_CPAS: RA Compare
+  // TC_IER_CPAS: RA Compare
+  tc->TC_CHANNEL[channel].TC_IER = TC_IER_CPAS;

  // Enables the timer clock and performs a software reset to start the counting
  TC_Start(tc, channel);
 }

-void initISR(const timer16_Sequence_t timer_index) {
-  CRITICAL_SECTION_START();
-  const bool disable_soon = DisablePending[timer_index];
-  DisablePending.clear(timer_index);
-  CRITICAL_SECTION_END();
-
-  if (!disable_soon) switch (timer_index) {
-    default: break;
-    #ifdef _useTimer1
-      case _timer1: return _initISR(TC_FOR_TIMER1, CHANNEL_FOR_TIMER1, ID_TC_FOR_TIMER1, IRQn_FOR_TIMER1);
-    #endif
-    #ifdef _useTimer2
-      case _timer2: return _initISR(TC_FOR_TIMER2, CHANNEL_FOR_TIMER2, ID_TC_FOR_TIMER2, IRQn_FOR_TIMER2);
-    #endif
-    #ifdef _useTimer3
-      case _timer3: return _initISR(TC_FOR_TIMER3, CHANNEL_FOR_TIMER3, ID_TC_FOR_TIMER3, IRQn_FOR_TIMER3);
-    #endif
-    #ifdef _useTimer4
-      case _timer4: return _initISR(TC_FOR_TIMER4, CHANNEL_FOR_TIMER4, ID_TC_FOR_TIMER4, IRQn_FOR_TIMER4);
-    #endif
-    #ifdef _useTimer5
-      case _timer5: return _initISR(TC_FOR_TIMER5, CHANNEL_FOR_TIMER5, ID_TC_FOR_TIMER5, IRQn_FOR_TIMER5);
-    #endif
-  }
+void initISR(timer16_Sequence_t timer) {
+  #ifdef _useTimer1
+    if (timer == _timer1)
+      _initISR(TC_FOR_TIMER1, CHANNEL_FOR_TIMER1, ID_TC_FOR_TIMER1, IRQn_FOR_TIMER1);
+  #endif
+  #ifdef _useTimer2
+    if (timer == _timer2)
+      _initISR(TC_FOR_TIMER2, CHANNEL_FOR_TIMER2, ID_TC_FOR_TIMER2, IRQn_FOR_TIMER2);
+  #endif
+  #ifdef _useTimer3
+    if (timer == _timer3)
+      _initISR(TC_FOR_TIMER3, CHANNEL_FOR_TIMER3, ID_TC_FOR_TIMER3, IRQn_FOR_TIMER3);
+  #endif
+  #ifdef _useTimer4
+    if (timer == _timer4)
+      _initISR(TC_FOR_TIMER4, CHANNEL_FOR_TIMER4, ID_TC_FOR_TIMER4, IRQn_FOR_TIMER4);
+  #endif
+  #ifdef _useTimer5
+    if (timer == _timer5)
+      _initISR(TC_FOR_TIMER5, CHANNEL_FOR_TIMER5, ID_TC_FOR_TIMER5, IRQn_FOR_TIMER5);
+  #endif
 }

-void finISR(const timer16_Sequence_t timer_index) {
-  // Timer is disabled from the ISR, to ensure proper final pulse length.
-  DisablePending.set(timer_index);
+void finISR(timer16_Sequence_t) {
+  #ifdef _useTimer1
+    TC_Stop(TC_FOR_TIMER1, CHANNEL_FOR_TIMER1);
+  #endif
+  #ifdef _useTimer2
+    TC_Stop(TC_FOR_TIMER2, CHANNEL_FOR_TIMER2);
+  #endif
+  #ifdef _useTimer3
+    TC_Stop(TC_FOR_TIMER3, CHANNEL_FOR_TIMER3);
+  #endif
+  #ifdef _useTimer4
+    TC_Stop(TC_FOR_TIMER4, CHANNEL_FOR_TIMER4);
+  #endif
+  #ifdef _useTimer5
+    TC_Stop(TC_FOR_TIMER5, CHANNEL_FOR_TIMER5);
+  #endif
 }

 #endif // HAS_SERVOS
@@ -37,7 +37,7 @@
 #define _useTimer5

 #define TRIM_DURATION             2   // compensation ticks to trim adjust for digitalWrite delays
-#define SERVO_TIMER_PRESCALER     2   // timer prescaler
+#define SERVO_TIMER_PRESCALER     32  // timer prescaler

 /*
  TC0, chan 0 => TC0_Handler
@@ -199,7 +199,8 @@ static bool ee_PageWrite(uint16_t page, const void *data) {
  for (i = 0; i <PageSize >> 2; i++)
    pageContents[i] = (((uint32_t*)data)[i]) | (~(pageContents[i] ^ ((uint32_t*)data)[i]));

-  DEBUG_ECHO_MSG("EEPROM PageWrite   ", page);
+  DEBUG_ECHO_START();
+  DEBUG_ECHOLNPGM("EEPROM PageWrite   ", page);
  DEBUG_ECHOLNPGM(" in FLASH address ", (uint32_t)addrflash);
  DEBUG_ECHOLNPGM(" base address     ", (uint32_t)getFlashStorage(0));
  DEBUG_FLUSH();
@@ -244,7 +245,8 @@ static bool ee_PageWrite(uint16_t page, const void *data) {
    // Reenable interrupts
    __enable_irq();

-    DEBUG_ECHO_MSG("EEPROM Unlock failure for page ", page);
+    DEBUG_ECHO_START();
+    DEBUG_ECHOLNPGM("EEPROM Unlock failure for page ", page);
    return false;
  }

@@ -268,7 +270,8 @@ static bool ee_PageWrite(uint16_t page, const void *data) {
    // Reenable interrupts
    __enable_irq();

-    DEBUG_ECHO_MSG("EEPROM Write failure for page ", page);
+    DEBUG_ECHO_START();
+    DEBUG_ECHOLNPGM("EEPROM Write failure for page ", page);

    return false;
  }
@@ -283,7 +286,8 @@ static bool ee_PageWrite(uint16_t page, const void *data) {
  if (memcmp(getFlashStorage(page),data,PageSize)) {

    #ifdef EE_EMU_DEBUG
-      DEBUG_ECHO_MSG("EEPROM Verify Write failure for page ", page);
+      DEBUG_ECHO_START();
+      DEBUG_ECHOLNPGM("EEPROM Verify Write failure for page ", page);

      ee_Dump( page, (uint32_t *)addrflash);
      ee_Dump(-page, data);
@@ -321,7 +325,8 @@ static bool ee_PageErase(uint16_t page) {
  uint16_t i;
  uint32_t addrflash = uint32_t(getFlashStorage(page));

-  DEBUG_ECHO_MSG("EEPROM PageErase  ", page);
+  DEBUG_ECHO_START();
+  DEBUG_ECHOLNPGM("EEPROM PageErase  ", page);
  DEBUG_ECHOLNPGM(" in FLASH address ", (uint32_t)addrflash);
  DEBUG_ECHOLNPGM(" base address     ", (uint32_t)getFlashStorage(0));
  DEBUG_FLUSH();
@@ -365,7 +370,8 @@ static bool ee_PageErase(uint16_t page) {
    // Reenable interrupts
    __enable_irq();

-    DEBUG_ECHO_MSG("EEPROM Unlock failure for page ",page);
+    DEBUG_ECHO_START();
+    DEBUG_ECHOLNPGM("EEPROM Unlock failure for page ",page);

    return false;
  }
@@ -388,7 +394,8 @@ static bool ee_PageErase(uint16_t page) {
    // Reenable interrupts
    __enable_irq();

-    DEBUG_ECHO_MSG("EEPROM Erase failure for page ",page);
+    DEBUG_ECHO_START();
+    DEBUG_ECHOLNPGM("EEPROM Erase failure for page ",page);

    return false;
  }
@@ -403,7 +410,8 @@ static bool ee_PageErase(uint16_t page) {
  uint32_t * aligned_src = (uint32_t *) addrflash;
  for (i = 0; i < PageSize >> 2; i++) {
    if (*aligned_src++ != 0xFFFFFFFF) {
-      DEBUG_ECHO_MSG("EEPROM Verify Erase failure for page ",page);
+      DEBUG_ECHO_START();
+      DEBUG_ECHOLNPGM("EEPROM Verify Erase failure for page ",page);
      ee_Dump(page, (uint32_t *)addrflash);
      return false;
    }
@@ -913,7 +921,8 @@ static void ee_Init() {
  // If all groups seem to be used, default to first group
  if (curGroup >= GroupCount) curGroup = 0;

-  DEBUG_ECHO_MSG("EEPROM Current Group: ",curGroup);
+  DEBUG_ECHO_START();
+  DEBUG_ECHOLNPGM("EEPROM Current Group: ",curGroup);
  DEBUG_FLUSH();

  // Now, validate that all the other group pages are empty
@@ -922,7 +931,8 @@ static void ee_Init() {

    for (int page = 0; page < PagesPerGroup; page++) {
      if (!ee_IsPageClean(grp * PagesPerGroup + page)) {
-        DEBUG_ECHO_MSG("EEPROM Page ", page, " not clean on group ", grp);
+        DEBUG_ECHO_START();
+        DEBUG_ECHOLNPGM("EEPROM Page ", page, " not clean on group ", grp);
        DEBUG_FLUSH();
        ee_PageErase(grp * PagesPerGroup + page);
      }
@@ -938,13 +948,15 @@ static void ee_Init() {
    }
  }

-  DEBUG_ECHO_MSG("EEPROM Active page: ", curPage);
+  DEBUG_ECHO_START();
+  DEBUG_ECHOLNPGM("EEPROM Active page: ", curPage);
  DEBUG_FLUSH();

  // Make sure the pages following the first clean one are also clean
  for (int page = curPage + 1; page < PagesPerGroup; page++) {
    if (!ee_IsPageClean(curGroup * PagesPerGroup + page)) {
-      DEBUG_ECHO_MSG("EEPROM Page ", page, " not clean on active group ", curGroup);
+      DEBUG_ECHO_START();
+      DEBUG_ECHOLNPGM("EEPROM Page ", page, " not clean on active group ", curGroup);
      DEBUG_FLUSH();
      ee_Dump(curGroup * PagesPerGroup + page, getFlashStorage(curGroup * PagesPerGroup + page));
      ee_PageErase(curGroup * PagesPerGroup + page);
@@ -25,30 +25,6 @@
 * Test Arduino Due specific configuration values for errors at compile-time.
 */

-/**
- * Check for common serial pin conflicts
- */
-#define CHECK_SERIAL_PIN(N) ( \
-     X_STOP_PIN == N || Y_STOP_PIN == N || Z_STOP_PIN == N \
-  || X_MIN_PIN  == N || Y_MIN_PIN  == N || Z_MIN_PIN  == N \
-  || X_MAX_PIN  == N || Y_MAX_PIN  == N || Z_MAX_PIN  == N \
-  || X_STEP_PIN == N || Y_STEP_PIN == N || Z_STEP_PIN == N \
-  || X_DIR_PIN  == N || Y_DIR_PIN  == N || Z_DIR_PIN  == N \
-  || X_ENA_PIN  == N || Y_ENA_PIN  == N || Z_ENA_PIN  == N \
-)
-#if SERIAL_IN_USE(0) // D0-D1. No known conflicts.
-#endif
-#if SERIAL_IN_USE(1) && (CHECK_SERIAL_PIN(18) || CHECK_SERIAL_PIN(19))
-  #error "Serial Port 1 pin D18 and/or D19 conflicts with another pin on the board."
-#endif
-#if SERIAL_IN_USE(2) && (CHECK_SERIAL_PIN(16) || CHECK_SERIAL_PIN(17))
-  #error "Serial Port 2 pin D16 and/or D17 conflicts with another pin on the board."
-#endif
-#if SERIAL_IN_USE(3) && (CHECK_SERIAL_PIN(14) || CHECK_SERIAL_PIN(15))
-  #error "Serial Port 3 pin D14 and/or D15 conflicts with another pin on the board."
-#endif
-#undef CHECK_SERIAL_PIN
-
 /**
 * HARDWARE VS. SOFTWARE SPI COMPATIBILITY
 *
@@ -70,7 +70,7 @@
 #define PRINT_PIN_ANALOG(p) do{ sprintf_P(buffer, PSTR(" (A%2d)  "), DIGITAL_PIN_TO_ANALOG_PIN(pin)); SERIAL_ECHO(buffer); }while(0)
 #define GET_ARRAY_PIN(p) pin_array[p].pin
 #define GET_ARRAY_IS_DIGITAL(p) pin_array[p].is_digital
-#define VALID_PIN(pin) (pin >= 0 && pin < int8_t(NUMBER_PINS_TOTAL))
+#define VALID_PIN(pin) (pin >= 0 && pin < (int8_t)NUMBER_PINS_TOTAL ? 1 : 0)
 #define DIGITAL_PIN_TO_ANALOG_PIN(p) int(p - analogInputToDigitalPin(0))
 #define IS_ANALOG(P) WITHIN(P, char(analogInputToDigitalPin(0)), char(analogInputToDigitalPin(NUM_ANALOG_INPUTS - 1)))
 #define pwm_status(pin) (((g_pinStatus[pin] & 0xF) == PIN_STATUS_PWM) && \
@@ -86,6 +86,7 @@ bool GET_PINMODE(int8_t pin) {  // 1: output, 0: input
          || pwm_status(pin));
 }

+
 void pwm_details(int32_t pin) {
  if (pwm_status(pin)) {
    uint32_t chan = g_APinDescription[pin].ulPWMChannel;
@@ -89,17 +89,10 @@ void HAL_timer_start(const uint8_t timer_num, const uint32_t frequency) {
  NVIC_SetPriority(irq, timer_config[timer_num].priority);

  // wave mode, reset counter on match with RC,
-  TC_Configure(tc, channel,
-      TC_CMR_WAVE
-    | TC_CMR_WAVSEL_UP_RC
-    | (HAL_TIMER_PRESCALER ==   2 ? TC_CMR_TCCLKS_TIMER_CLOCK1 : 0)
-    | (HAL_TIMER_PRESCALER ==   8 ? TC_CMR_TCCLKS_TIMER_CLOCK2 : 0)
-    | (HAL_TIMER_PRESCALER ==  32 ? TC_CMR_TCCLKS_TIMER_CLOCK3 : 0)
-    | (HAL_TIMER_PRESCALER == 128 ? TC_CMR_TCCLKS_TIMER_CLOCK4 : 0)
-  );
+  TC_Configure(tc, channel, TC_CMR_WAVE | TC_CMR_WAVSEL_UP_RC | TC_CMR_TCCLKS_TIMER_CLOCK1);

  // Set compare value
-  TC_SetRC(tc, channel, VARIANT_MCK / (HAL_TIMER_PRESCALER) / frequency);
+  TC_SetRC(tc, channel, VARIANT_MCK / 2 / frequency);

  // And start timer
  TC_Start(tc, channel);
@@ -35,8 +35,7 @@
 typedef uint32_t hal_timer_t;
 #define HAL_TIMER_TYPE_MAX 0xFFFFFFFF

-#define HAL_TIMER_PRESCALER    2
-#define HAL_TIMER_RATE         ((F_CPU) / (HAL_TIMER_PRESCALER))  // frequency of timers peripherals
+#define HAL_TIMER_RATE         ((F_CPU) / 2)    // frequency of timers peripherals

 #ifndef MF_TIMER_STEP
  #define MF_TIMER_STEP         2  // Timer Index for Stepper
@@ -6,14 +6,14 @@
 #
 import pioutil
 if pioutil.is_pio_build():
-    import platform
-    current_OS = platform.system()
+	import platform
+	current_OS = platform.system()

-    if current_OS == 'Windows':
+	if current_OS == 'Windows':

-        Import("env")
+		Import("env")

-        # Use bossac.exe on Windows
-        env.Replace(
-            UPLOADCMD="bossac --info --unlock --write --verify --reset --erase -U false --boot $SOURCE"
-        )
+		# Use bossac.exe on Windows
+		env.Replace(
+			UPLOADCMD="bossac --info --unlock --write --verify --reset --erase -U false --boot $SOURCE"
+		)
@@ -1059,7 +1059,7 @@ static inline void convert_64_bit_to_byte_array(uint64_t value, uint8_t *data)
    while (val_index < 8)
    {
        data[val_index++] = value & 0xFF;
-        value >>= 8;
+        value = value >> 8;
    }
 }

@@ -62,7 +62,7 @@ void usb_task_idle(void) {
    // Attend SD card access from the USB MSD -- Prioritize access to improve speed
    int delay = 2;
    while (main_b_msc_enable && --delay > 0) {
-      if (udi_msc_process_trans()) delay = 20;
+      if (udi_msc_process_trans()) delay = 10000;

      // Reset the watchdog, just to be sure
      REG_WDT_CR = WDT_CR_WDRSTT | WDT_CR_KEY(0xA5);
@@ -0,0 +1,114 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef ARDUINO_ARCH_SAM
+
+#include "../../inc/MarlinConfig.h"
+#include "../../MarlinCore.h"
+#include "watchdog.h"
+
+// Override Arduino runtime to either config or disable the watchdog
+//
+// We need to configure the watchdog as soon as possible in the boot
+// process, because watchdog initialization at hardware reset on SAM3X8E
+// is unreliable, and there is risk of unintended resets if we delay
+// that initialization to a later time.
+void watchdogSetup() {
+
+  #if ENABLED(USE_WATCHDOG)
+
+    // 4 seconds timeout
+    uint32_t timeout = TERN(WATCHDOG_DURATION_8S, 8000, 4000);
+
+    // Calculate timeout value in WDT counter ticks: This assumes
+    // the slow clock is running at 32.768 kHz watchdog
+    // frequency is therefore 32768 / 128 = 256 Hz
+    timeout = (timeout << 8) / 1000;
+    if (timeout == 0)
+      timeout = 1;
+    else if (timeout > 0xFFF)
+      timeout = 0xFFF;
+
+    // We want to enable the watchdog with the specified timeout
+    uint32_t value =
+      WDT_MR_WDV(timeout) |               // With the specified timeout
+      WDT_MR_WDD(timeout) |               // and no invalid write window
+    #if !(SAMV70 || SAMV71 || SAME70 || SAMS70)
+      WDT_MR_WDRPROC   |                  // WDT fault resets processor only - We want
+                                          // to keep PIO controller state
+    #endif
+      WDT_MR_WDDBGHLT  |                  // WDT stops in debug state.
+      WDT_MR_WDIDLEHLT;                   // WDT stops in idle state.
+
+    #if ENABLED(WATCHDOG_RESET_MANUAL)
+      // We enable the watchdog timer, but only for the interrupt.
+
+      // Configure WDT to only trigger an interrupt
+      value |= WDT_MR_WDFIEN;             // Enable WDT fault interrupt.
+
+      // Disable WDT interrupt (just in case, to avoid triggering it!)
+      NVIC_DisableIRQ(WDT_IRQn);
+
+      // We NEED memory barriers to ensure Interrupts are actually disabled!
+      // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
+      __DSB();
+      __ISB();
+
+      // Initialize WDT with the given parameters
+      WDT_Enable(WDT, value);
+
+      // Configure and enable WDT interrupt.
+      NVIC_ClearPendingIRQ(WDT_IRQn);
+      NVIC_SetPriority(WDT_IRQn, 0); // Use highest priority, so we detect all kinds of lockups
+      NVIC_EnableIRQ(WDT_IRQn);
+
+    #else
+
+      // a WDT fault triggers a reset
+      value |= WDT_MR_WDRSTEN;
+
+      // Initialize WDT with the given parameters
+      WDT_Enable(WDT, value);
+
+    #endif
+
+    // Reset the watchdog
+    WDT_Restart(WDT);
+
+  #else
+
+    // Make sure to completely disable the Watchdog
+    WDT_Disable(WDT);
+
+  #endif
+}
+
+#if ENABLED(USE_WATCHDOG)
+  // Initialize watchdog - On SAM3X, Watchdog was already configured
+  //  and enabled or disabled at startup, so no need to reconfigure it
+  //  here.
+  void watchdog_init() {
+    // Reset watchdog to start clean
+    WDT_Restart(WDT);
+  }
+#endif // USE_WATCHDOG
+
+#endif
@@ -0,0 +1,33 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+// Arduino Due core now has watchdog support
+
+#include "HAL.h"
+
+// Initialize watchdog with a 4 second interrupt time
+void watchdog_init();
+
+// Reset watchdog. MUST be called at least every 4 seconds after the
+// first watchdog_init or AVR will go into emergency procedures.
+inline void HAL_watchdog_refresh() { watchdogReset(); }
@@ -65,7 +65,6 @@ portMUX_TYPE MarlinHAL::spinlock = portMUX_INITIALIZER_UNLOCKED;
 // ------------------------

 uint16_t MarlinHAL::adc_result;
-pwm_pin_t MarlinHAL::pwm_pin_data[MAX_EXPANDER_BITS];

 // ------------------------
 // Private Variables
@@ -180,31 +179,6 @@ void _delay_ms(int delay_ms) { delay(delay_ms); }
 // return free memory between end of heap (or end bss) and whatever is current
 int MarlinHAL::freeMemory() { return ESP.getFreeHeap(); }

-// ------------------------
-// Watchdog Timer
-// ------------------------
-
-#if ENABLED(USE_WATCHDOG)
-
-  #define WDT_TIMEOUT_US TERN(WATCHDOG_DURATION_8S, 8000000, 4000000) // 4 or 8 second timeout
-
-  extern "C" {
-    esp_err_t esp_task_wdt_reset();
-  }
-
-  void watchdogSetup() {
-    // do whatever. don't remove this function.
-  }
-
-  void MarlinHAL::watchdog_init() {
-    // TODO
-  }
-
-  // Reset watchdog.
-  void MarlinHAL::watchdog_refresh() { esp_task_wdt_reset(); }
-
-#endif
-
 // ------------------------
 // ADC
 // ------------------------
@@ -331,46 +305,21 @@ int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res)
 }

 void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=_BV(PWM_RESOLUTION)-1*/, const bool invert/*=false*/) {
-  #if ENABLED(I2S_STEPPER_STREAM)
-    if (pin > 127) {
-      const uint8_t pinlo = pin & 0x7F;
-      pwm_pin_t &pindata = pwm_pin_data[pinlo];
-      const uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, pindata.pwm_cycle_ticks);
-      if (duty == 0 || duty == pindata.pwm_cycle_ticks) { // max or min (i.e., on/off)
-        pindata.pwm_duty_ticks = 0;  // turn off PWM for this pin
-        duty ? SBI32(i2s_port_data, pinlo) : CBI32(i2s_port_data, pinlo); // set pin level
-      }
-      else
-        pindata.pwm_duty_ticks = duty; // PWM duty count = # of 4µs ticks per full PWM cycle
-    }
-    else
-  #endif
-    {
-      const int8_t cid = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
-      if (cid >= 0) {
-        const uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
-        ledcWrite(cid, duty);
-      }
-    }
+  const int8_t cid = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
+  if (cid >= 0) {
+    uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
+    ledcWrite(cid, duty);
+  }
 }

 int8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
-  #if ENABLED(I2S_STEPPER_STREAM)
-    if (pin > 127) {
-      pwm_pin_data[pin & 0x7F].pwm_cycle_ticks = 1000000UL / f_desired / 4; // # of 4µs ticks per full PWM cycle
-      return 0;
-    }
-    else
-  #endif
-    {
-      const int8_t cid = channel_for_pin(pin);
-      if (cid >= 0) {
-        if (f_desired == ledcReadFreq(cid)) return cid; // no freq change
-        ledcDetachPin(chan_pin[cid]);
-        chan_pin[cid] = 0;              // remove old freq channel
-      }
-      return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
-    }
+  const int8_t cid = channel_for_pin(pin);
+  if (cid >= 0) {
+    if (f_desired == ledcReadFreq(cid)) return cid; // no freq change
+    ledcDetachPin(chan_pin[cid]);
+    chan_pin[cid] = 0;              // remove old freq channel
+  }
+  return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
 }

 // use hardware PWM if avail, if not then ISR
@@ -32,6 +32,7 @@
 #include "../shared/HAL_SPI.h"

 #include "fastio.h"
+#include "watchdog.h"
 #include "i2s.h"

 #if ENABLED(WIFISUPPORT)
@@ -60,17 +61,14 @@
  #endif
 #endif

-#define CRITICAL_SECTION_START() portENTER_CRITICAL(&hal.spinlock)
-#define CRITICAL_SECTION_END()   portEXIT_CRITICAL(&hal.spinlock)
+#define CRITICAL_SECTION_START() portENTER_CRITICAL(&spinlock)
+#define CRITICAL_SECTION_END()   portEXIT_CRITICAL(&spinlock)

 #define HAL_CAN_SET_PWM_FREQ   // This HAL supports PWM Frequency adjustment
 #define PWM_FREQUENCY  1000u   // Default PWM frequency when set_pwm_duty() is called without set_pwm_frequency()
 #define PWM_RESOLUTION   10u   // Default PWM bit resolution
 #define CHANNEL_MAX_NUM  15u   // max PWM channel # to allocate (7 to only use low speed, 15 to use low & high)
 #define MAX_PWM_IOPIN    33u   // hardware pwm pins < 34
-#ifndef MAX_EXPANDER_BITS
-  #define MAX_EXPANDER_BITS 32 // I2S expander bit width (max 32)
-#endif

 // ------------------------
 // Types
@@ -79,12 +77,6 @@
 typedef double isr_float_t;   // FPU ops are used for single-precision, so use double for ISRs.
 typedef int16_t pin_t;

-typedef struct pwm_pin {
-  uint32_t pwm_cycle_ticks = 1000000UL / (PWM_FREQUENCY) / 4; // # ticks per pwm cycle
-  uint32_t pwm_tick_count = 0;  // current tick count
-  uint32_t pwm_duty_ticks = 0;  // # of ticks for current duty cycle
-} pwm_pin_t;
-
 class Servo;
 typedef Servo hal_servo_t;

@@ -97,7 +89,7 @@ typedef Servo hal_servo_t;
 //
 void tone(const pin_t _pin, const unsigned int frequency, const unsigned long duration=0);
 void noTone(const pin_t _pin);
-int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res);
+
 void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq=PWM_FREQUENCY, const uint16_t res=8);

 //
@@ -180,13 +172,9 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  // Watchdog
-  static void watchdog_init()    IF_DISABLED(USE_WATCHDOG, {});
-  static void watchdog_refresh() IF_DISABLED(USE_WATCHDOG, {});
-
-  static void init() {}        // Called early in setup()
-  static void init_board();    // Called less early in setup()
-  static void reboot();        // Restart the firmware
+  static void init() {}  // Called early in setup()
+  static void init_board();     // Called less early in setup()
+  static void reboot();         // Restart the firmware

  // Interrupts
  static portMUX_TYPE spinlock;
@@ -206,8 +194,6 @@ public:
  // Free SRAM
  static int freeMemory();

-  static pwm_pin_t pwm_pin_data[MAX_EXPANDER_BITS];
-
  //
  // ADC Methods
  //
@@ -139,40 +139,22 @@ static void IRAM_ATTR i2s_intr_handler_default(void *arg) {
 }

 void stepperTask(void *parameter) {
-  uint32_t nextMainISR = 0;
-  #if ENABLED(LIN_ADVANCE)
-    uint32_t nextAdvanceISR = Stepper::LA_ADV_NEVER;
-  #endif
+  uint32_t remaining = 0;

-  for (;;) {
+  while (1) {
    xQueueReceive(dma.queue, &dma.current, portMAX_DELAY);
    dma.rw_pos = 0;

    while (dma.rw_pos < DMA_SAMPLE_COUNT) {
      // Fill with the port data post pulse_phase until the next step
-      if (nextMainISR && TERN1(LIN_ADVANCE, nextAdvanceISR))
+      if (remaining) {
        i2s_push_sample();
-
-      // i2s_push_sample() is also called from Stepper::pulse_phase_isr() and Stepper::advance_isr()
-      // in a rare case where both are called, we need to double decrement the counters
-      const uint8_t push_count = 1 + (!nextMainISR && TERN0(LIN_ADVANCE, !nextAdvanceISR));
-
-      #if ENABLED(LIN_ADVANCE)
-        if (!nextAdvanceISR) {
-          Stepper::advance_isr();
-          nextAdvanceISR = Stepper::la_interval;
-        }
-        else if (nextAdvanceISR == Stepper::LA_ADV_NEVER)
-          nextAdvanceISR = Stepper::la_interval;
-      #endif
-
-      if (!nextMainISR) {
-        Stepper::pulse_phase_isr();
-        nextMainISR = Stepper::block_phase_isr();
+        remaining--;
+      }
+      else {
+        Stepper::pulse_phase_isr();
+        remaining = Stepper::block_phase_isr();
      }
-
-      nextMainISR -= push_count;
-      TERN_(LIN_ADVANCE, nextAdvanceISR -= push_count);
    }
  }
 }
@@ -355,26 +337,6 @@ uint8_t i2s_state(uint8_t pin) {
 }

 void i2s_push_sample() {
-  // Every 4µs (when space in DMA buffer) toggle each expander PWM output using
-  // the current duty cycle/frequency so they sync with any steps (once
-  // through the DMA/FIFO buffers).  PWM signal inversion handled by other functions
-  LOOP_L_N(p, MAX_EXPANDER_BITS) {
-    if (hal.pwm_pin_data[p].pwm_duty_ticks > 0) { // pin has active pwm?
-      if (hal.pwm_pin_data[p].pwm_tick_count == 0) {
-        if (TEST32(i2s_port_data, p)) {  // hi->lo
-          CBI32(i2s_port_data, p);
-          hal.pwm_pin_data[p].pwm_tick_count = hal.pwm_pin_data[p].pwm_cycle_ticks - hal.pwm_pin_data[p].pwm_duty_ticks;
-        }
-        else { // lo->hi
-          SBI32(i2s_port_data, p);
-          hal.pwm_pin_data[p].pwm_tick_count = hal.pwm_pin_data[p].pwm_duty_ticks;
-        }
-      }
-      else
-        hal.pwm_pin_data[p].pwm_tick_count--;
-    }
-  }
-
  dma.current[dma.rw_pos++] = i2s_port_data;
 }

@@ -20,10 +20,3 @@
 *
 */
 #pragma once
-
-//
-// Board-specific options need to be defined before HAL.h
-//
-#if MB(MKS_TINYBEE)
-  #define MAX_EXPANDER_BITS 24  // TinyBee has 3 x HC595
-#endif
@@ -45,14 +45,6 @@
  #error "FAST_PWM_FAN is not available on TinyBee."
 #endif

-#if BOTH(I2S_STEPPER_STREAM, BABYSTEPPING) && DISABLED(INTEGRATED_BABYSTEPPING)
-  #error "BABYSTEPPING on I2S stream requires INTEGRATED_BABYSTEPPING."
-#endif
-
 #if USING_PULLDOWNS
  #error "PULLDOWN pin mode is not available on ESP32 boards."
 #endif
-
-#if BOTH(I2S_STEPPER_STREAM, LIN_ADVANCE) && DISABLED(EXPERIMENTAL_I2S_LA)
-  #error "I2S stream is currently incompatible with LIN_ADVANCE."
-#endif
@@ -23,24 +23,24 @@
 */
 #ifdef ARDUINO_ARCH_ESP32

-#include "../../inc/MarlinConfig.h"
+#include "../../inc/MarlinConfigPre.h"

-#if EITHER(MKS_MINI_12864, FYSETC_MINI_12864_2_1)
+#if ENABLED(FYSETC_MINI_12864_2_1)

 #include <U8glib-HAL.h>
+#include "Arduino.h"
 #include "../shared/HAL_SPI.h"
 #include "HAL.h"
 #include "SPI.h"

-#if ENABLED(SDSUPPORT)
-  #include "../../sd/cardreader.h"
-  #if ENABLED(ESP3D_WIFISUPPORT)
-    #include "sd_ESP32.h"
-  #endif
-#endif
-
 static SPISettings spiConfig;

+#define MDOGLCD_MOSI    23
+#define MDOGLCD_SCK     18
+#define MLCD_RESET_PIN   0
+#define MLCD_PINS_DC     4
+#define MDOGLCD_CS      21
+#define MDOGLCD_A0       4

 #ifndef LCD_SPI_SPEED
  #ifdef SD_SPI_SPEED
@@ -52,11 +52,6 @@ static SPISettings spiConfig;

 uint8_t u8g_eps_hw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_ptr) {
  static uint8_t msgInitCount = 2; // Ignore all messages until 2nd U8G_COM_MSG_INIT
-
-  #if ENABLED(PAUSE_LCD_FOR_BUSY_SD)
-    if (card.flag.saving || card.flag.logging || TERN0(ESP3D_WIFISUPPORT, sd_busy_lock == true)) return 0;
-  #endif
-
  if (msgInitCount) {
    if (msg == U8G_COM_MSG_INIT) msgInitCount--;
    if (msgInitCount) return -1;
@@ -66,24 +61,24 @@ uint8_t u8g_eps_hw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_pt
    case U8G_COM_MSG_STOP: break;

    case U8G_COM_MSG_INIT:
-      OUT_WRITE(DOGLCD_CS, HIGH);
-      OUT_WRITE(DOGLCD_A0, HIGH);
-      OUT_WRITE(LCD_RESET_PIN, HIGH);
+      OUT_WRITE(MDOGLCD_CS, HIGH);
+      OUT_WRITE(MDOGLCD_A0, HIGH);
+      OUT_WRITE(MLCD_RESET_PIN, HIGH);
      u8g_Delay(5);
      spiBegin();
      spiInit(LCD_SPI_SPEED);
      break;

    case U8G_COM_MSG_ADDRESS:           /* define cmd (arg_val = 0) or data mode (arg_val = 1) */
-      WRITE(DOGLCD_A0, arg_val ? HIGH : LOW);
+      WRITE(MDOGLCD_A0, arg_val ? HIGH : LOW);
      break;

    case U8G_COM_MSG_CHIP_SELECT:       /* arg_val == 0 means HIGH level of U8G_PI_CS */
-      WRITE(DOGLCD_CS, arg_val ? LOW : HIGH);
+      WRITE(MDOGLCD_CS, arg_val ? LOW : HIGH);
      break;

    case U8G_COM_MSG_RESET:
-      WRITE(LCD_RESET_PIN, arg_val);
+      WRITE(MLCD_RESET_PIN, arg_val);
      break;

    case U8G_COM_MSG_WRITE_BYTE:
@@ -101,6 +96,5 @@ uint8_t u8g_eps_hw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_val, void *arg_pt
  return 1;
 }

-#endif // EITHER(MKS_MINI_12864, FYSETC_MINI_12864_2_1)
-
+#endif // FYSETC_MINI_12864_2_1
 #endif // ARDUINO_ARCH_ESP32
@@ -0,0 +1,42 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef ARDUINO_ARCH_ESP32
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(USE_WATCHDOG)
+
+#define WDT_TIMEOUT_US TERN(WATCHDOG_DURATION_8S, 8000000, 4000000) // 4 or 8 second timeout
+
+#include "watchdog.h"
+
+void watchdogSetup() {
+  // do whatever. don't remove this function.
+}
+
+void watchdog_init() {
+  // TODO
+}
+
+#endif // USE_WATCHDOG
+
+#endif // ARDUINO_ARCH_ESP32
@@ -0,0 +1,38 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+  esp_err_t esp_task_wdt_reset();
+
+#ifdef __cplusplus
+  }
+#endif
+
+// Initialize watchdog with a 4 second interrupt time
+void watchdog_init();
+
+// Reset watchdog.
+inline void HAL_watchdog_refresh() { esp_task_wdt_reset(); }
@@ -28,7 +28,6 @@
 #endif

 #include HAL_PATH(.,HAL.h)
-extern MarlinHAL hal;

 #define HAL_ADC_RANGE _BV(HAL_ADC_RESOLUTION)

@@ -45,3 +44,7 @@ extern MarlinHAL hal;
 #ifndef PGMSTR
  #define PGMSTR(NAM,STR) const char NAM[] = STR
 #endif
+
+inline void watchdog_refresh() {
+  TERN_(USE_WATCHDOG, HAL_watchdog_refresh());
+}
@@ -21,8 +21,6 @@
 */
 #pragma once

-#include "../../inc/MarlinConfigPre.h"
-
 #include <iostream>
 #include <stdint.h>
 #include <stdarg.h>
@@ -31,10 +29,12 @@
 #include <algorithm>

 #include "hardware/Clock.h"
+
 #include "../shared/Marduino.h"
 #include "../shared/math_32bit.h"
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
+#include "watchdog.h"
 #include "serial.h"

 // ------------------------
@@ -106,13 +106,9 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  // Watchdog
-  static void watchdog_init() {}
-  static void watchdog_refresh() {}
-
  static void init() {}        // Called early in setup()
  static void init_board() {}  // Called less early in setup()
-  static void reboot();        // Reset the application state and GPIO
+  static void reboot();               // Reset the application state and GPIO

  // Interrupts
  static bool isr_state() { return true; }
@@ -69,12 +69,12 @@ bool PersistentStore::write_data(int &pos, const uint8_t *value, size_t size, ui
  std::size_t bytes_written = 0;

  for (std::size_t i = 0; i < size; i++) {
-    buffer[pos + i] = value[i];
-    bytes_written++;
+    buffer[pos+i] = value[i];
+    bytes_written ++;
  }

  crc16(crc, value, size);
-  pos += size;
+  pos = pos + size;
  return (bytes_written != size);  // return true for any error
 }

@@ -82,21 +82,21 @@ bool PersistentStore::read_data(int &pos, uint8_t *value, const size_t size, uin
  std::size_t bytes_read = 0;
  if (writing) {
    for (std::size_t i = 0; i < size; i++) {
-      value[i] = buffer[pos + i];
-      bytes_read++;
+      value[i] = buffer[pos+i];
+      bytes_read ++;
    }
    crc16(crc, value, size);
  }
  else {
    uint8_t temp[size];
    for (std::size_t i = 0; i < size; i++) {
-      temp[i] = buffer[pos + i];
-      bytes_read++;
+      temp[i] = buffer[pos+i];
+      bytes_read ++;
    }
    crc16(crc, temp, size);
  }

-  pos += size;
+  pos = pos + size;
  return bytes_read != size;  // return true for any error
 }

@@ -26,8 +26,8 @@
 struct LowpassFilter {
  uint64_t data_delay = 0;
  uint16_t update(uint16_t value) {
-    data_delay += value - (data_delay >> 6);
-    return uint16_t(data_delay >> 6);
+    data_delay = data_delay - (data_delay >> 6) + value;
+    return (uint16_t)(data_delay >> 6);
  }
 };

@@ -0,0 +1,37 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef __PLAT_LINUX__
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(USE_WATCHDOG)
+
+#include "watchdog.h"
+
+#define WDT_TIMEOUT_US TERN(WATCHDOG_DURATION_8S, 8000000, 4000000) // 4 or 8 second timeout
+
+void watchdog_init() {}
+void HAL_watchdog_refresh() {}
+
+#endif
+
+#endif // __PLAT_LINUX__
@@ -1,6 +1,6 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2022 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
@@ -21,5 +21,5 @@
 */
 #pragma once

-void runStartupTests();
-void runPeriodicTests();
+void watchdog_init();
+void HAL_watchdog_refresh();
@@ -25,6 +25,10 @@
 #include "../shared/Delay.h"
 #include "../../../gcode/parser.h"

+#if ENABLED(USE_WATCHDOG)
+  #include "watchdog.h"
+#endif
+
 DefaultSerial1 USBSerial(false, UsbSerial);

 uint32_t MarlinHAL::adc_result = 0;
@@ -57,7 +61,9 @@ uint8_t MarlinHAL::get_reset_source() {
  return RST_POWER_ON;
 }

-void MarlinHAL::clear_reset_source() { watchdog_clear_timeout_flag(); }
+void MarlinHAL::clear_reset_source() {
+  TERN_(USE_WATCHDOG, watchdog_clear_timeout_flag());
+}

 void flashFirmware(const int16_t) {
  delay(500);          // Give OS time to disconnect
@@ -66,52 +72,6 @@ void flashFirmware(const int16_t) {
  hal.reboot();
 }

-#if ENABLED(USE_WATCHDOG)
-
-  #include <lpc17xx_wdt.h>
-
-  #define WDT_TIMEOUT_US TERN(WATCHDOG_DURATION_8S, 8000000, 4000000) // 4 or 8 second timeout
-
-  void MarlinHAL::watchdog_init() {
-    #if ENABLED(WATCHDOG_RESET_MANUAL)
-      // We enable the watchdog timer, but only for the interrupt.
-
-      // Configure WDT to only trigger an interrupt
-      // Disable WDT interrupt (just in case, to avoid triggering it!)
-      NVIC_DisableIRQ(WDT_IRQn);
-
-      // We NEED memory barriers to ensure Interrupts are actually disabled!
-      // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
-      __DSB();
-      __ISB();
-
-      // Configure WDT to only trigger an interrupt
-      // Initialize WDT with the given parameters
-      WDT_Init(WDT_CLKSRC_IRC, WDT_MODE_INT_ONLY);
-
-      // Configure and enable WDT interrupt.
-      NVIC_ClearPendingIRQ(WDT_IRQn);
-      NVIC_SetPriority(WDT_IRQn, 0); // Use highest priority, so we detect all kinds of lockups
-      NVIC_EnableIRQ(WDT_IRQn);
-    #else
-      WDT_Init(WDT_CLKSRC_IRC, WDT_MODE_RESET);
-    #endif
-    WDT_Start(WDT_TIMEOUT_US);
-  }
-
-  void MarlinHAL::watchdog_refresh() {
-    WDT_Feed();
-    #if DISABLED(PINS_DEBUGGING) && PIN_EXISTS(LED)
-      TOGGLE(LED_PIN);  // heartbeat indicator
-    #endif
-  }
-
-  // Timeout state
-  bool MarlinHAL::watchdog_timed_out() { return TEST(WDT_ReadTimeOutFlag(), 0); }
-  void MarlinHAL::watchdog_clear_timeout_flag() { WDT_ClrTimeOutFlag(); }
-
-#endif // USE_WATCHDOG
-
 // For M42/M43, scan command line for pin code
 //   return index into pin map array if found and the pin is valid.
 //   return dval if not found or not a valid pin.
@@ -38,6 +38,7 @@ extern "C" volatile uint32_t _millis;
 #include "../shared/math_32bit.h"
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
+#include "watchdog.h"
 #include "MarlinSerial.h"

 #include <adc.h>
@@ -176,7 +177,7 @@ void flashFirmware(const int16_t);
 #define CPU_ST7920_DELAY_3 750

 // ------------------------
-// Free Memory Accessor
+// Class Utilities
 // ------------------------

 #pragma GCC diagnostic push
@@ -198,9 +199,9 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  static void init();          // Called early in setup()
+  static void init();                 // Called early in setup()
  static void init_board() {}  // Called less early in setup()
-  static void reboot();        // Restart the firmware from 0x0
+  static void reboot();               // Restart the firmware from 0x0

  // Interrupts
  static bool isr_state() { return !__get_PRIMASK(); }
@@ -209,12 +210,6 @@ public:

  static void delay_ms(const int ms) { _delay_ms(ms); }

-  // Watchdog
-  static void watchdog_init() IF_DISABLED(USE_WATCHDOG, {});
-  static void watchdog_refresh() IF_DISABLED(USE_WATCHDOG, {});
-  static bool watchdog_timed_out() IF_DISABLED(USE_WATCHDOG, { return false; });
-  static void watchdog_clear_timeout_flag() IF_DISABLED(USE_WATCHDOG, {});
-
  // Tasks, called from idle()
  static void idletask();

@@ -26,7 +26,7 @@

 #if ENABLED(POSTMORTEM_DEBUGGING)

-#include "../shared/MinSerial.h"
+#include "../shared/HAL_MinSerial.h"
 #include <debug_frmwrk.h>

 static void TX(char c) { _DBC(c); }
@@ -34,7 +34,7 @@
 #include "../shared/eeprom_api.h"

 #ifndef MARLIN_EEPROM_SIZE
-  #define MARLIN_EEPROM_SIZE           0x8000 // 32K
+  #define MARLIN_EEPROM_SIZE           0x8000 // 32KB‬
 #endif
 size_t PersistentStore::capacity()    { return MARLIN_EEPROM_SIZE; }

@@ -29,6 +29,6 @@

 // LPC1768 boards seem to lose steps when saving to EEPROM during print (issue #20785)
 // TODO: Which other boards are incompatible?
-#if defined(MCU_LPC1768) && ENABLED(FLASH_EEPROM_EMULATION) && PRINTCOUNTER_SAVE_INTERVAL > 0
+#if defined(MCU_LPC1768) && PRINTCOUNTER_SAVE_INTERVAL > 0
  #define PRINTCOUNTER_SYNC 1
 #endif
@@ -9,127 +9,119 @@ from __future__ import print_function
 import pioutil
 if pioutil.is_pio_build():

-    target_filename = "FIRMWARE.CUR"
-    target_drive = "REARM"
+	target_filename = "FIRMWARE.CUR"
+	target_drive = "REARM"

-    import platform
+	import os,getpass,platform

-    current_OS = platform.system()
-    Import("env")
+	current_OS = platform.system()
+	Import("env")

-    def print_error(e):
-        print('\nUnable to find destination disk (%s)\n' \
-              'Please select it in platformio.ini using the upload_port keyword ' \
-              '(https://docs.platformio.org/en/latest/projectconf/section_env_upload.html) ' \
-              'or copy the firmware (.pio/build/%s/firmware.bin) manually to the appropriate disk\n' \
-              %(e, env.get('PIOENV')))
+	def print_error(e):
+		print('\nUnable to find destination disk (%s)\n' \
+			  'Please select it in platformio.ini using the upload_port keyword ' \
+			  '(https://docs.platformio.org/en/latest/projectconf/section_env_upload.html) ' \
+			  'or copy the firmware (.pio/build/%s/firmware.bin) manually to the appropriate disk\n' \
+			  %(e, env.get('PIOENV')))

-    def before_upload(source, target, env):
-        try:
-            from pathlib import Path
-            #
-            # Find a disk for upload
-            #
-            upload_disk = 'Disk not found'
-            target_file_found = False
-            target_drive_found = False
-            if current_OS == 'Windows':
-                #
-                # platformio.ini will accept this for a Windows upload port designation: 'upload_port = L:'
-                #   Windows - doesn't care about the disk's name, only cares about the drive letter
-                import subprocess,string
-                from ctypes import windll
-                from pathlib import PureWindowsPath
+	def before_upload(source, target, env):
+		try:
+			#
+			# Find a disk for upload
+			#
+			upload_disk = 'Disk not found'
+			target_file_found = False
+			target_drive_found = False
+			if current_OS == 'Windows':
+				#
+				# platformio.ini will accept this for a Windows upload port designation: 'upload_port = L:'
+				#   Windows - doesn't care about the disk's name, only cares about the drive letter
+				import subprocess,string
+				from ctypes import windll

-                # getting list of drives
-                # https://stackoverflow.com/questions/827371/is-there-a-way-to-list-all-the-available-drive-letters-in-python
-                drives = []
-                bitmask = windll.kernel32.GetLogicalDrives()
-                for letter in string.ascii_uppercase:
-                    if bitmask & 1:
-                        drives.append(letter)
-                    bitmask >>= 1
+				# getting list of drives
+				# https://stackoverflow.com/questions/827371/is-there-a-way-to-list-all-the-available-drive-letters-in-python
+				drives = []
+				bitmask = windll.kernel32.GetLogicalDrives()
+				for letter in string.ascii_uppercase:
+					if bitmask & 1:
+						drives.append(letter)
+					bitmask >>= 1

-                for drive in drives:
-                    final_drive_name = drive + ':'
-                    # print ('disc check: {}'.format(final_drive_name))
-                    try:
-                        volume_info = str(subprocess.check_output('cmd /C dir ' + final_drive_name, stderr=subprocess.STDOUT))
-                    except Exception as e:
-                        print ('error:{}'.format(e))
-                        continue
-                    else:
-                        if target_drive in volume_info and not target_file_found:  # set upload if not found target file yet
-                            target_drive_found = True
-                            upload_disk = PureWindowsPath(final_drive_name)
-                        if target_filename in volume_info:
-                            if not target_file_found:
-                                upload_disk = PureWindowsPath(final_drive_name)
-                            target_file_found = True
+				for drive in drives:
+					final_drive_name = drive + ':\\'
+					# print ('disc check: {}'.format(final_drive_name))
+					try:
+						volume_info = str(subprocess.check_output('cmd /C dir ' + final_drive_name, stderr=subprocess.STDOUT))
+					except Exception as e:
+						print ('error:{}'.format(e))
+						continue
+					else:
+						if target_drive in volume_info and not target_file_found:  # set upload if not found target file yet
+							target_drive_found = True
+							upload_disk = final_drive_name
+						if target_filename in volume_info:
+							if not target_file_found:
+								upload_disk = final_drive_name
+							target_file_found = True

-            elif current_OS == 'Linux':
-                #
-                # platformio.ini will accept this for a Linux upload port designation: 'upload_port = /media/media_name/drive'
-                #
-                import getpass
-                user = getpass.getuser()
-                mpath = Path('/media', user)
-                drives = [ x for x in mpath.iterdir() if x.is_dir() ]
-                if target_drive in drives:  # If target drive is found, use it.
-                    target_drive_found = True
-                    upload_disk = mpath / target_drive
-                else:
-                    for drive in drives:
-                        try:
-                            fpath = mpath / drive
-                            filenames = [ x.name for x in fpath.iterdir() if x.is_file() ]
-                        except:
-                            continue
-                        else:
-                            if target_filename in filenames:
-                                upload_disk = mpath / drive
-                                target_file_found = True
-                                break
-                #
-                # set upload_port to drive if found
-                #
+			elif current_OS == 'Linux':
+				#
+				# platformio.ini will accept this for a Linux upload port designation: 'upload_port = /media/media_name/drive'
+				#
+				drives = os.listdir(os.path.join(os.sep, 'media', getpass.getuser()))
+				if target_drive in drives:  # If target drive is found, use it.
+					target_drive_found = True
+					upload_disk = os.path.join(os.sep, 'media', getpass.getuser(), target_drive) + os.sep
+				else:
+					for drive in drives:
+						try:
+							files = os.listdir(os.path.join(os.sep, 'media', getpass.getuser(), drive))
+						except:
+							continue
+						else:
+							if target_filename in files:
+								upload_disk = os.path.join(os.sep, 'media', getpass.getuser(), drive) + os.sep
+								target_file_found = True
+								break
+				#
+				# set upload_port to drive if found
+				#

-                if target_file_found or target_drive_found:
-                    env.Replace(
-                        UPLOAD_FLAGS="-P$UPLOAD_PORT"
-                    )
+				if target_file_found or target_drive_found:
+					env.Replace(
+						UPLOAD_FLAGS="-P$UPLOAD_PORT"
+					)

-            elif current_OS == 'Darwin':  # MAC
-                #
-                # platformio.ini will accept this for a OSX upload port designation: 'upload_port = /media/media_name/drive'
-                #
-                dpath = Path('/Volumes')  # human readable names
-                drives = [ x for x in dpath.iterdir() if x.is_dir() ]
-                if target_drive in drives and not target_file_found:  # set upload if not found target file yet
-                    target_drive_found = True
-                    upload_disk = dpath / target_drive
-                for drive in drives:
-                    try:
-                        fpath = dpath / drive   # will get an error if the drive is protected
-                        filenames = [ x.name for x in fpath.iterdir() if x.is_file() ]
-                    except:
-                        continue
-                    else:
-                        if target_filename in filenames:
-                            upload_disk = dpath / drive
-                            target_file_found = True
-                            break
+			elif current_OS == 'Darwin':  # MAC
+				#
+				# platformio.ini will accept this for a OSX upload port designation: 'upload_port = /media/media_name/drive'
+				#
+				drives = os.listdir('/Volumes')  # human readable names
+				if target_drive in drives and not target_file_found:  # set upload if not found target file yet
+					target_drive_found = True
+					upload_disk = '/Volumes/' + target_drive + '/'
+				for drive in drives:
+					try:
+						filenames = os.listdir('/Volumes/' + drive + '/')   # will get an error if the drive is protected
+					except:
+						continue
+					else:
+						if target_filename in filenames:
+							if not target_file_found:
+								upload_disk = '/Volumes/' + drive + '/'
+							target_file_found = True

-            #
-            # Set upload_port to drive if found
-            #
-            if target_file_found or target_drive_found:
-                env.Replace(UPLOAD_PORT=str(upload_disk))
-                print('\nUpload disk: ', upload_disk, '\n')
-            else:
-                print_error('Autodetect Error')
+			#
+			# Set upload_port to drive if found
+			#
+			if target_file_found or target_drive_found:
+				env.Replace(UPLOAD_PORT=upload_disk)
+				print('\nUpload disk: ', upload_disk, '\n')
+			else:
+				print_error('Autodetect Error')

-        except Exception as e:
-            print_error(str(e))
+		except Exception as e:
+			print_error(str(e))

-    env.AddPreAction("upload", before_upload)
+	env.AddPreAction("upload", before_upload)
@@ -0,0 +1,72 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef TARGET_LPC1768
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(USE_WATCHDOG)
+
+#include <lpc17xx_wdt.h>
+#include "watchdog.h"
+
+#define WDT_TIMEOUT_US TERN(WATCHDOG_DURATION_8S, 8000000, 4000000) // 4 or 8 second timeout
+
+void watchdog_init() {
+  #if ENABLED(WATCHDOG_RESET_MANUAL)
+    // We enable the watchdog timer, but only for the interrupt.
+
+    // Configure WDT to only trigger an interrupt
+    // Disable WDT interrupt (just in case, to avoid triggering it!)
+    NVIC_DisableIRQ(WDT_IRQn);
+
+    // We NEED memory barriers to ensure Interrupts are actually disabled!
+    // ( https://dzone.com/articles/nvic-disabling-interrupts-on-arm-cortex-m-and-the )
+    __DSB();
+    __ISB();
+
+    // Configure WDT to only trigger an interrupt
+    // Initialize WDT with the given parameters
+    WDT_Init(WDT_CLKSRC_IRC, WDT_MODE_INT_ONLY);
+
+    // Configure and enable WDT interrupt.
+    NVIC_ClearPendingIRQ(WDT_IRQn);
+    NVIC_SetPriority(WDT_IRQn, 0); // Use highest priority, so we detect all kinds of lockups
+    NVIC_EnableIRQ(WDT_IRQn);
+  #else
+    WDT_Init(WDT_CLKSRC_IRC, WDT_MODE_RESET);
+  #endif
+  WDT_Start(WDT_TIMEOUT_US);
+}
+
+void HAL_watchdog_refresh() {
+  WDT_Feed();
+  #if DISABLED(PINS_DEBUGGING) && PIN_EXISTS(LED)
+    TOGGLE(LED_PIN);  // heartbeat indicator
+  #endif
+}
+
+// Timeout state
+bool watchdog_timed_out() { return TEST(WDT_ReadTimeOutFlag(), 0); }
+void watchdog_clear_timeout_flag() { WDT_ClrTimeOutFlag(); }
+
+#endif // USE_WATCHDOG
+#endif // TARGET_LPC1768
@@ -1,6 +1,6 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2022 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
@@ -21,6 +21,8 @@
 */
 #pragma once

-#define BOARD_INFO_NAME "BTT SKR V3 EZ"
+void watchdog_init();
+void HAL_watchdog_refresh();

-#include "pins_BTT_SKR_V3_0_common.h"
+bool watchdog_timed_out();
+void watchdog_clear_timeout_flag();
@@ -45,6 +45,7 @@ uint8_t _getc();
 #include "../shared/math_32bit.h"
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
+#include "watchdog.h"
 #include "serial.h"

 // ------------------------
@@ -185,7 +186,7 @@ constexpr inline char* strstr_constexpr(char* str, const char* target) {
 }

 // ------------------------
-// Free Memory Accessor
+// Class Utilities
 // ------------------------

 #pragma GCC diagnostic push
@@ -207,10 +208,6 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  // Watchdog
-  static void watchdog_init()    IF_DISABLED(USE_WATCHDOG, {});
-  static void watchdog_refresh() IF_DISABLED(USE_WATCHDOG, {});
-
  static void init() {}        // Called early in setup()
  static void init_board() {}  // Called less early in setup()
  static void reboot();        // Restart the firmware from 0x0
@@ -44,7 +44,7 @@
 *
 * Now you can simply SET_OUTPUT(STEP); WRITE(STEP, HIGH); WRITE(STEP, LOW);
 *
- * Why double up on these macros? see https://gcc.gnu.org/onlinedocs/cpp/Stringification.html
+ * Why double up on these macros? see http://gcc.gnu.org/onlinedocs/cpp/Stringification.html
 */

 /// Read a pin
@@ -51,7 +51,7 @@ enum XPTCoordinate : uint8_t {
  XPT2046_Z2 = 0x40 | XPT2046_CONTROL | XPT2046_DFR_MODE,
 };

-#ifndef XPT2046_Z1_THRESHOLD
+#if !defined(XPT2046_Z1_THRESHOLD)
  #define XPT2046_Z1_THRESHOLD 10
 #endif

@@ -38,13 +38,13 @@
 #ifdef __cplusplus
  extern "C" {
 #endif
-
-void u8g_SetPinOutput(uint8_t internal_pin_number) { SET_DIR_OUTPUT(internal_pin_number); }
-void u8g_SetPinInput(uint8_t internal_pin_number) { SET_DIR_INPUT(internal_pin_number); }
-void u8g_SetPinLevel(uint8_t pin, uint8_t pin_status) { WRITE_PIN(pin, pin_status); }
-uint8_t u8g_GetPinLevel(uint8_t pin) { return READ_PIN(pin); }
-void usleep(uint64_t microsec) { assert(false); /* why we here? */ }
-
+void u8g_SetPinOutput(uint8_t internal_pin_number){SET_DIR_OUTPUT(internal_pin_number);}
+void u8g_SetPinInput(uint8_t internal_pin_number){SET_DIR_INPUT(internal_pin_number);}
+void u8g_SetPinLevel(uint8_t  pin, uint8_t  pin_status){WRITE_PIN(pin, pin_status);}
+uint8_t u8g_GetPinLevel(uint8_t pin){return READ_PIN(pin);}
+void usleep(uint64_t microsec){
+assert(false); // why we here?
+}
 #ifdef __cplusplus
  }
 #endif
@@ -1,6 +1,6 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2022 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
@@ -21,6 +21,7 @@
 */
 #pragma once

-#define BOARD_INFO_NAME      "BTT SKR SE BX V3.0"
+#define WDT_TIMEOUT   4000000 // 4 second timeout

-#include "pins_BTT_SKR_SE_BX_common.h"
+void watchdog_init();
+void HAL_watchdog_refresh();
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -19,10 +18,6 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-
-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
 #ifdef __SAMD51__

 #include "../../inc/MarlinConfig.h"
@@ -208,40 +203,6 @@ enum ADCIndex {
  ADC_COUNT
 };

-#if ENABLED(USE_WATCHDOG)
-
-  #define WDT_TIMEOUT_REG TERN(WATCHDOG_DURATION_8S, WDT_CONFIG_PER_CYC8192, WDT_CONFIG_PER_CYC4096) // 4 or 8 second timeout
-
-  void MarlinHAL::watchdog_init() {
-    // The low-power oscillator used by the WDT runs at 32,768 Hz with
-    // a 1:32 prescale, thus 1024 Hz, though probably not super precise.
-
-    // Setup WDT clocks
-    MCLK->APBAMASK.bit.OSC32KCTRL_ = true;
-    MCLK->APBAMASK.bit.WDT_ = true;
-    OSC32KCTRL->OSCULP32K.bit.EN1K = true;  // Enable out 1K (this is what WDT uses)
-
-    WDT->CTRLA.bit.ENABLE = false;          // Disable watchdog for config
-    SYNC(WDT->SYNCBUSY.bit.ENABLE);
-
-    WDT->INTENCLR.reg = WDT_INTENCLR_EW;    // Disable early warning interrupt
-    WDT->CONFIG.reg = WDT_TIMEOUT_REG;      // Set a 4s or 8s period for chip reset
-
-    hal.watchdog_refresh();
-
-    WDT->CTRLA.reg = WDT_CTRLA_ENABLE;      // Start watchdog now in normal mode
-    SYNC(WDT->SYNCBUSY.bit.ENABLE);
-  }
-
-  // Reset watchdog. MUST be called at least every 4 seconds after the
-  // first watchdog_init or SAMD will go into emergency procedures.
-  void MarlinHAL::watchdog_refresh() {
-    SYNC(WDT->SYNCBUSY.bit.CLEAR);        // Test first if previous is 'ongoing' to save time waiting for command execution
-    WDT->CLEAR.reg = WDT_CLEAR_CLEAR_KEY;
-  }
-
-#endif
-
 // ------------------------
 // Types
 // ------------------------
@@ -603,7 +564,7 @@ void MarlinHAL::dma_init() {
 void MarlinHAL::init() {
  TERN_(DMA_IS_REQUIRED, dma_init());
  #if ENABLED(SDSUPPORT)
-    #if HAS_SD_DETECT && SD_CONNECTION_IS(ONBOARD)
+    #if SD_CONNECTION_IS(ONBOARD) && PIN_EXISTS(SD_DETECT)
      SET_INPUT_PULLUP(SD_DETECT_PIN);
    #endif
    OUT_WRITE(SDSS, HIGH);  // Try to set SDSS inactive before any other SPI users start up
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,16 +20,13 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 #define CPU_32_BIT

 #include "../shared/Marduino.h"
 #include "../shared/math_32bit.h"
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
+#include "watchdog.h"

 #ifdef ADAFRUIT_GRAND_CENTRAL_M4
  #include "MarlinSerial_AGCM4.h"
@@ -161,10 +157,6 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  // Watchdog
-  static void watchdog_init()    IF_DISABLED(USE_WATCHDOG, {});
-  static void watchdog_refresh() IF_DISABLED(USE_WATCHDOG, {});
-
  static void init();          // Called early in setup()
  static void init_board() {}  // Called less early in setup()
  static void reboot();        // Restart the firmware from 0x0
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -20,10 +19,6 @@
 *
 */

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 /**
 * Hardware and software SPI implementations are included in this file.
 *
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -19,10 +18,6 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-
-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
 #ifdef ADAFRUIT_GRAND_CENTRAL_M4

 /**
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 #include "../../core/serial_hook.h"

 typedef Serial1Class<Uart> UartT;
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 #define SYNC(sc)    while (sc) {  \
                      asm("");    \
                    }
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -20,10 +19,6 @@
 *
 */

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 /**
 * This comes from Arduino library which at the moment is buggy and uncompilable
 */
@@ -82,8 +77,7 @@ HAL_SERVO_TIMER_ISR() {
  ;
  const uint8_t tcChannel = TIMER_TCCHANNEL(timer);

-  int8_t cho = currentServoIndex[timer];                // Handle the prior servo first
-  if (cho < 0) {                                        // Servo -1 indicates the refresh interval completed...
+  if (currentServoIndex[timer] < 0) {
    #if defined(_useTimer1) && defined(_useTimer2)
      if (currentServoIndex[timer ^ 1] >= 0) {
        // Wait for both channels
@@ -92,37 +86,45 @@ HAL_SERVO_TIMER_ISR() {
        return;
      }
    #endif
-    tc->COUNT16.COUNT.reg = TC_COUNTER_START_VAL;       // ...so reset the timer
+    tc->COUNT16.COUNT.reg = TC_COUNTER_START_VAL;
    SYNC(tc->COUNT16.SYNCBUSY.bit.COUNT);
  }
-  else if (SERVO_INDEX(timer, cho) < ServoCount)        // prior channel handled?
-    digitalWrite(SERVO(timer, cho).Pin.nbr, LOW);       // pulse the prior channel LOW
+  else if (SERVO_INDEX(timer, currentServoIndex[timer]) < ServoCount && SERVO(timer, currentServoIndex[timer]).Pin.isActive)
+    digitalWrite(SERVO(timer, currentServoIndex[timer]).Pin.nbr, LOW);      // pulse this channel low if activated

-  currentServoIndex[timer] = ++cho;                     // go to the next channel (or 0)
-  if (cho < SERVOS_PER_TIMER && SERVO_INDEX(timer, cho) < ServoCount) {
-    if (SERVO(timer, cho).Pin.isActive)                 // activated?
-      digitalWrite(SERVO(timer, cho).Pin.nbr, HIGH);    // yes: pulse HIGH
+  // Select the next servo controlled by this timer
+  currentServoIndex[timer]++;

-    tc->COUNT16.CC[tcChannel].reg = getTimerCount() - (uint16_t)SERVO(timer, cho).ticks;
+  if (SERVO_INDEX(timer, currentServoIndex[timer]) < ServoCount && currentServoIndex[timer] < SERVOS_PER_TIMER) {
+    if (SERVO(timer, currentServoIndex[timer]).Pin.isActive)                // check if activated
+      digitalWrite(SERVO(timer, currentServoIndex[timer]).Pin.nbr, HIGH);   // it's an active channel so pulse it high
+
+    tc->COUNT16.CC[tcChannel].reg = getTimerCount() - (uint16_t)SERVO(timer, currentServoIndex[timer]).ticks;
  }
  else {
    // finished all channels so wait for the refresh period to expire before starting over
-    currentServoIndex[timer] = -1;                                          // reset the timer COUNT.reg on the next call
-    const uint16_t cval = getTimerCount() - 256 / (SERVO_TIMER_PRESCALER),  // allow 256 cycles to ensure the next CV not missed
-                   ival = (TC_COUNTER_START_VAL) - (uint16_t)usToTicks(REFRESH_INTERVAL); // at least REFRESH_INTERVAL has elapsed
-    tc->COUNT16.CC[tcChannel].reg = min(cval, ival);
+    currentServoIndex[timer] = -1;   // this will get incremented at the end of the refresh period to start again at the first channel
+
+    const uint16_t tcCounterValue = getTimerCount();
+
+    if ((TC_COUNTER_START_VAL - tcCounterValue) + 4UL < usToTicks(REFRESH_INTERVAL))  // allow a few ticks to ensure the next OCR1A not missed
+      tc->COUNT16.CC[tcChannel].reg = TC_COUNTER_START_VAL - (uint16_t)usToTicks(REFRESH_INTERVAL);
+    else
+      tc->COUNT16.CC[tcChannel].reg = (uint16_t)(tcCounterValue - 4UL);               // at least REFRESH_INTERVAL has elapsed
  }
  if (tcChannel == 0) {
    SYNC(tc->COUNT16.SYNCBUSY.bit.CC0);
-    tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC0; // Clear the interrupt
+    // Clear the interrupt
+    tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC0;
  }
  else {
    SYNC(tc->COUNT16.SYNCBUSY.bit.CC1);
-    tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC1; // Clear the interrupt
+    // Clear the interrupt
+    tc->COUNT16.INTFLAG.reg = TC_INTFLAG_MC1;
  }
 }

-void initISR(const timer16_Sequence_t timer) {
+void initISR(timer16_Sequence_t timer) {
  Tc * const tc = timer_config[SERVO_TC].pTc;
  const uint8_t tcChannel = TIMER_TCCHANNEL(timer);

@@ -199,9 +201,9 @@ void initISR(const timer16_Sequence_t timer) {
  }
 }

-void finISR(const timer16_Sequence_t timer_index) {
+void finISR(timer16_Sequence_t timer) {
  Tc * const tc = timer_config[SERVO_TC].pTc;
-  const uint8_t tcChannel = TIMER_TCCHANNEL(timer_index);
+  const uint8_t tcChannel = TIMER_TCCHANNEL(timer);

  // Disable the match channel interrupt request
  tc->COUNT16.INTENCLR.reg = (tcChannel == 0) ? TC_INTENCLR_MC0 : TC_INTENCLR_MC1;
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 #define _useTimer1
 #define _useTimer2

@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -19,10 +18,6 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-
-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
 #ifdef __SAMD51__

 #include "../../inc/MarlinConfig.h"
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -19,10 +18,6 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-
-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
 #ifdef __SAMD51__

 #include "../../inc/MarlinConfig.h"
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -19,10 +18,6 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-
-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
 #ifdef __SAMD51__

 #include "../../inc/MarlinConfig.h"
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 /**
 * Endstop interrupts for ATMEL SAMD51 based targets.
 *
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 /**
 * Fast IO functions for SAMD51
 */
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -19,11 +18,6 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-#pragma once
-
-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */

 /**
 * Test SAMD51 specific configuration values for errors at compile-time.
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 #define NUMBER_PINS_TOTAL PINS_COUNT

 #define digitalRead_mod(p) extDigitalRead(p)
@@ -34,7 +29,7 @@
 #define PRINT_PIN_ANALOG(p) do{ sprintf_P(buffer, PSTR(" (A%2d)  "), DIGITAL_PIN_TO_ANALOG_PIN(pin)); SERIAL_ECHO(buffer); }while(0)
 #define GET_ARRAY_PIN(p) pin_array[p].pin
 #define GET_ARRAY_IS_DIGITAL(p) pin_array[p].is_digital
-#define VALID_PIN(pin) (pin >= 0 && pin < int8_t(NUMBER_PINS_TOTAL))
+#define VALID_PIN(pin) (pin >= 0 && pin < (int8_t)NUMBER_PINS_TOTAL)
 #define DIGITAL_PIN_TO_ANALOG_PIN(p) digitalPinToAnalogInput(p)
 #define IS_ANALOG(P) (DIGITAL_PIN_TO_ANALOG_PIN(P)!=-1)
 #define pwm_status(pin) digitalPinHasPWM(pin)
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 #ifdef ADAFRUIT_GRAND_CENTRAL_M4

 /*
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -19,10 +18,6 @@
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
-
-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
 #ifdef __SAMD51__

 // --------------------------------------------------------------------------
@@ -1,9 +1,8 @@
 /**
 * Marlin 3D Printer Firmware
- * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,10 +20,6 @@
 */
 #pragma once

-/**
- * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
- */
-
 #include <stdint.h>

 // --------------------------------------------------------------------------
@@ -0,0 +1,54 @@
+/**
+ * Marlin 3D Printer Firmware
+ *
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#ifdef __SAMD51__
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(USE_WATCHDOG)
+
+#include "watchdog.h"
+
+#define WDT_TIMEOUT_REG TERN(WATCHDOG_DURATION_8S, WDT_CONFIG_PER_CYC8192, WDT_CONFIG_PER_CYC4096) // 4 or 8 second timeout
+
+void watchdog_init() {
+  // The low-power oscillator used by the WDT runs at 32,768 Hz with
+  // a 1:32 prescale, thus 1024 Hz, though probably not super precise.
+
+  // Setup WDT clocks
+  MCLK->APBAMASK.bit.OSC32KCTRL_ = true;
+  MCLK->APBAMASK.bit.WDT_ = true;
+  OSC32KCTRL->OSCULP32K.bit.EN1K = true;      // Enable out 1K (this is what WDT uses)
+
+  WDT->CTRLA.bit.ENABLE = false;              // Disable watchdog for config
+  SYNC(WDT->SYNCBUSY.bit.ENABLE);
+
+  WDT->INTENCLR.reg = WDT_INTENCLR_EW;        // Disable early warning interrupt
+  WDT->CONFIG.reg = WDT_TIMEOUT_REG;          // Set a 4s or 8s period for chip reset
+
+  HAL_watchdog_refresh();
+
+  WDT->CTRLA.reg = WDT_CTRLA_ENABLE;          // Start watchdog now in normal mode
+  SYNC(WDT->SYNCBUSY.bit.ENABLE);
+}
+
+#endif // USE_WATCHDOG
+
+#endif // __SAMD51__
@@ -0,0 +1,31 @@
+/**
+ * Marlin 3D Printer Firmware
+ *
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ * SAMD51 HAL developed by Giuliano Zaro (AKA GMagician)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+// Initialize watchdog with a 4 second interrupt time
+void watchdog_init();
+
+// Reset watchdog. MUST be called at least every 4 seconds after the
+// first watchdog_init or SAMD will go into emergency procedures.
+inline void HAL_watchdog_refresh() {
+  SYNC(WDT->SYNCBUSY.bit.CLEAR);        // Test first if previous is 'ongoing' to save time waiting for command execution
+  WDT->CLEAR.reg = WDT_CLEAR_CLEAR_KEY;
+}
@@ -24,13 +24,14 @@

 #ifdef HAL_STM32

+#include "HAL.h"
+#include "usb_serial.h"
+
 #include "../../inc/MarlinConfig.h"
 #include "../shared/Delay.h"

-#include "usb_serial.h"
-
 #ifdef USBCON
-  DefaultSerial1 MSerialUSB(false, SerialUSB);
+  DefaultSerial1 MSerial0(false, SerialUSB);
 #endif

 #if ENABLED(SRAM_EEPROM_EMULATION)
@@ -140,29 +141,6 @@ uint8_t MarlinHAL::get_reset_source() {

 void MarlinHAL::clear_reset_source() { __HAL_RCC_CLEAR_RESET_FLAGS(); }

-// ------------------------
-// Watchdog Timer
-// ------------------------
-
-#if ENABLED(USE_WATCHDOG)
-
-  #define WDT_TIMEOUT_US TERN(WATCHDOG_DURATION_8S, 8000000, 4000000) // 4 or 8 second timeout
-
-  #include <IWatchdog.h>
-
-  void MarlinHAL::watchdog_init() {
-    IF_DISABLED(DISABLE_WATCHDOG_INIT, IWatchdog.begin(WDT_TIMEOUT_US));
-  }
-
-  void MarlinHAL::watchdog_refresh() {
-    IWatchdog.reload();
-    #if DISABLED(PINS_DEBUGGING) && PIN_EXISTS(LED)
-      TOGGLE(LED_PIN);  // heartbeat indicator
-    #endif
-  }
-
-#endif
-
 extern "C" {
  extern unsigned int _ebss; // end of bss section
 }
@@ -30,6 +30,7 @@
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
 #include "Servo.h"
+#include "watchdog.h"
 #include "MarlinSerial.h"

 #include "../../inc/MarlinConfigPre.h"
@@ -50,67 +51,57 @@
  #include <USBSerial.h>
  #include "../../core/serial_hook.h"
  typedef ForwardSerial1Class< decltype(SerialUSB) > DefaultSerial1;
-  extern DefaultSerial1 MSerialUSB;
+  extern DefaultSerial1 MSerial0;
 #endif

 #define _MSERIAL(X) MSerial##X
 #define MSERIAL(X) _MSERIAL(X)

-#if WITHIN(SERIAL_PORT, 1, 6)
+#if SERIAL_PORT == -1
+  #define MYSERIAL1 MSerial0
+#elif WITHIN(SERIAL_PORT, 1, 6)
  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#elif !defined(USBCON)
-  #error "SERIAL_PORT must be from 1 to 6."
-#elif SERIAL_PORT == -1
-  #define MYSERIAL1 MSerialUSB
 #else
-  #error "SERIAL_PORT must be from 1 to 6, or -1 for Native USB."
+  #error "SERIAL_PORT must be from 1 to 6. You can also use -1 if the board supports Native USB."
 #endif

 #ifdef SERIAL_PORT_2
-  #if WITHIN(SERIAL_PORT_2, 1, 6)
+  #if SERIAL_PORT_2 == -1
+    #define MYSERIAL2 MSerial0
+  #elif WITHIN(SERIAL_PORT_2, 1, 6)
    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #elif !defined(USBCON)
-    #error "SERIAL_PORT must be from 1 to 6."
-  #elif SERIAL_PORT_2 == -1
-    #define MYSERIAL2 MSerialUSB
  #else
-    #error "SERIAL_PORT_2 must be from 1 to 6, or -1 for Native USB."
+    #error "SERIAL_PORT_2 must be from 1 to 6. You can also use -1 if the board supports Native USB."
  #endif
 #endif

 #ifdef SERIAL_PORT_3
-  #if WITHIN(SERIAL_PORT_3, 1, 6)
+  #if SERIAL_PORT_3 == -1
+    #define MYSERIAL3 MSerial0
+  #elif WITHIN(SERIAL_PORT_3, 1, 6)
    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #elif !defined(USBCON)
-    #error "SERIAL_PORT must be from 1 to 6."
-  #elif SERIAL_PORT_3 == -1
-    #define MYSERIAL3 MSerialUSB
  #else
-    #error "SERIAL_PORT_3 must be from 1 to 6, or -1 for Native USB."
+    #error "SERIAL_PORT_3 must be from 1 to 6. You can also use -1 if the board supports Native USB."
  #endif
 #endif

 #ifdef MMU2_SERIAL_PORT
-  #if WITHIN(MMU2_SERIAL_PORT, 1, 6)
+  #if MMU2_SERIAL_PORT == -1
+    #define MMU2_SERIAL MSerial0
+  #elif WITHIN(MMU2_SERIAL_PORT, 1, 6)
    #define MMU2_SERIAL MSERIAL(MMU2_SERIAL_PORT)
-  #elif !defined(USBCON)
-    #error "SERIAL_PORT must be from 1 to 6."
-  #elif MMU2_SERIAL_PORT == -1
-    #define MMU2_SERIAL MSerialUSB
  #else
-    #error "MMU2_SERIAL_PORT must be from 1 to 6, or -1 for Native USB."
+    #error "MMU2_SERIAL_PORT must be from 1 to 6. You can also use -1 if the board supports Native USB."
  #endif
 #endif

 #ifdef LCD_SERIAL_PORT
-  #if WITHIN(LCD_SERIAL_PORT, 1, 6)
+  #if LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL MSerial0
+  #elif WITHIN(LCD_SERIAL_PORT, 1, 6)
    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #elif !defined(USBCON)
-    #error "SERIAL_PORT must be from 1 to 6."
-  #elif LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL MSerialUSB
  #else
-    #error "LCD_SERIAL_PORT must be from 1 to 6, or -1 for Native USB."
+    #error "LCD_SERIAL_PORT must be from 1 to 6. You can also use -1 if the board supports Native USB."
  #endif
  #if HAS_DGUS_LCD
    #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
@@ -217,13 +208,9 @@ public:
  // Earliest possible init, before setup()
  MarlinHAL() {}

-  // Watchdog
-  static void watchdog_init()    IF_DISABLED(USE_WATCHDOG, {});
-  static void watchdog_refresh() IF_DISABLED(USE_WATCHDOG, {});
-
-  static void init();          // Called early in setup()
+  static void init();                 // Called early in setup()
  static void init_board() {}  // Called less early in setup()
-  static void reboot();        // Restart the firmware from 0x0
+  static void reboot();               // Restart the firmware from 0x0

  // Interrupts
  static bool isr_state() { return !__get_PRIMASK(); }
@@ -28,7 +28,8 @@

 #if ENABLED(POSTMORTEM_DEBUGGING)

-#include "../shared/MinSerial.h"
+#include "../shared/HAL_MinSerial.h"
+#include "watchdog.h"

 /* Instruction Synchronization Barrier */
 #define isb() __asm__ __volatile__ ("isb" : : : "memory")
@@ -119,7 +120,7 @@ static void TX(char c) {
  #if WITHIN(SERIAL_PORT, 1, 6)
    constexpr uint32_t usart_sr_txe = _BV(7);
    while (!(regs->SR & usart_sr_txe)) {
-      hal.watchdog_refresh();
+      TERN_(USE_WATCHDOG, HAL_watchdog_refresh());
      sw_barrier();
    }
    regs->DR = c;
@@ -95,7 +95,7 @@
  static_assert(IS_FLASH_SECTOR(FLASH_SECTOR), "FLASH_SECTOR is invalid");
  static_assert(IS_POWER_OF_2(FLASH_UNIT_SIZE), "FLASH_UNIT_SIZE should be a power of 2, please check your chip's spec sheet");

-#endif // FLASH_EEPROM_LEVELING
+#endif

 static bool eeprom_data_written = false;

@@ -189,15 +189,15 @@ bool PersistentStore::access_finish() {

      UNLOCK_FLASH();

-      uint32_t offset = 0,
-               address = SLOT_ADDRESS(current_slot),
-               address_end = address + MARLIN_EEPROM_SIZE,
-               data = 0;
+      uint32_t offset = 0;
+      uint32_t address = SLOT_ADDRESS(current_slot);
+      uint32_t address_end = address + MARLIN_EEPROM_SIZE;
+      uint32_t data = 0;

      bool success = true;

      while (address < address_end) {
-        memcpy(&data, ram_eeprom + offset, sizeof(data));
+        memcpy(&data, ram_eeprom + offset, sizeof(uint32_t));
        status = HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, address, data);
        if (status == HAL_OK) {
          address += sizeof(uint32_t);
@@ -221,8 +221,7 @@ bool PersistentStore::access_finish() {

      return success;

-    #else // !FLASH_EEPROM_LEVELING
-
+    #else
      // The following was written for the STM32F4 but may work with other MCUs as well.
      // Most STM32F4 flash does not allow reading from flash during erase operations.
      // This takes about a second on a STM32F407 with a 128kB sector used as EEPROM.
@@ -236,8 +235,7 @@ bool PersistentStore::access_finish() {
      TERN_(HAS_PAUSE_SERVO_OUTPUT, RESUME_SERVO_OUTPUT());

      eeprom_data_written = false;
-
-    #endif // !FLASH_EEPROM_LEVELING
+    #endif
  }

  return true;
@@ -27,8 +27,3 @@
 #elif EITHER(I2C_EEPROM, SPI_EEPROM)
  #define USE_SHARED_EEPROM 1
 #endif
-
-// Some STM32F4 boards may lose steps when saving to EEPROM during print (PR #17946)
-#if defined(STM32F4xx) && ENABLED(FLASH_EEPROM_EMULATION) && PRINTCOUNTER_SAVE_INTERVAL > 0
-  #define PRINTCOUNTER_SYNC 1
-#endif
@@ -37,6 +37,11 @@
  #error "SDCARD_EEPROM_EMULATION requires SDSUPPORT. Enable SDSUPPORT or choose another EEPROM emulation."
 #endif

+#if defined(STM32F4xx) && BOTH(PRINTCOUNTER, FLASH_EEPROM_EMULATION)
+  #warning "FLASH_EEPROM_EMULATION may cause long delays when writing and should not be used while printing."
+  #error "Disable PRINTCOUNTER or choose another EEPROM emulation."
+#endif
+
 #if !defined(STM32F4xx) && ENABLED(FLASH_EEPROM_LEVELING)
  #error "FLASH_EEPROM_LEVELING is currently only supported on STM32F4 hardware."
 #endif
@@ -50,62 +55,3 @@
 #if ANY(TFT_COLOR_UI, TFT_LVGL_UI, TFT_CLASSIC_UI) && NOT_TARGET(STM32H7xx, STM32F4xx, STM32F1xx)
  #error "TFT_COLOR_UI, TFT_LVGL_UI and TFT_CLASSIC_UI are currently only supported on STM32H7, STM32F4 and STM32F1 hardware."
 #endif
-
-/**
- * Check for common serial pin conflicts
- */
-#define _CHECK_SERIAL_PIN(N) (( \
-    BTN_EN1 == N || DOGLCD_CS == N || HEATER_BED_PIN == N || FAN_PIN == N || \
-    SDIO_D2_PIN == N || SDIO_D3_PIN == N || SDIO_CK_PIN == N || SDIO_CMD_PIN == N \
-  ))
-#define CHECK_SERIAL_PIN(T,N) defined(UART##N##_##T##_PIN) && _CHECK_SERIAL_PIN(UART##N##_##T##_PIN)
-#if SERIAL_IN_USE(1)
-  #if CHECK_SERIAL_PIN(TX,1)
-    #error "Serial Port 1 TX IO pins conflict with another pin on the board."
-  #endif
-  #if CHECK_SERIAL_PIN(RX,1)
-    #error "Serial Port 1 RX IO pins conflict with another pin on the board."
-  #endif
-#endif
-#if SERIAL_IN_USE(2)
-  #if CHECK_SERIAL_PIN(TX,2)
-    #error "Serial Port 2 TX IO pins conflict with another pin on the board."
-  #endif
-  #if CHECK_SERIAL_PIN(RX,2)
-    #error "Serial Port 2 RX IO pins conflict with another pin on the board."
-  #endif
-#endif
-#if SERIAL_IN_USE(3)
-  #if CHECK_SERIAL_PIN(TX,3)
-    #error "Serial Port 3 TX IO pins conflict with another pin on the board."
-  #endif
-  #if CHECK_SERIAL_PIN(RX,3)
-    #error "Serial Port 3 RX IO pins conflict with another pin on the board."
-  #endif
-#endif
-#if SERIAL_IN_USE(4)
-  #if CHECK_SERIAL_PIN(TX,4)
-    #error "Serial Port 4 TX IO pins conflict with another pin on the board."
-  #endif
-  #if CHECK_SERIAL_PIN(RX,4)
-    #error "Serial Port 4 RX IO pins conflict with another pin on the board."
-  #endif
-#endif
-#if SERIAL_IN_USE(5)
-  #if CHECK_SERIAL_PIN(TX,5)
-    #error "Serial Port 5 TX IO pins conflict with another pin on the board."
-  #endif
-  #if CHECK_SERIAL_PIN(RX,5)
-    #error "Serial Port 5 RX IO pins conflict with another pin on the board."
-  #endif
-#endif
-#if SERIAL_IN_USE(6)
-  #if CHECK_SERIAL_PIN(TX,6)
-    #error "Serial Port 6 TX IO pins conflict with another pin on the board."
-  #endif
-  #if CHECK_SERIAL_PIN(RX,6)
-    #error "Serial Port 6 RX IO pins conflict with another pin on the board."
-  #endif
-#endif
-#undef CHECK_SERIAL_PIN
-#undef _CHECK_SERIAL_PIN
--- a/Show More
+++ b/Show More