grblHAL for Arduino Portenta H7 and Arduino Giga

[yusnimawl]

Hi everyone,

I'm not a software engineer, but I want to create a grblHAL driver for:

• Arduino Portenta H7 (and Lite Connected variant)
• Arduino Giga R1

Both boards use the STM32H7 chip with HRTIM timers that seem perfect for step pulse generation.

Where I need guidance:

1. Best starting point?
   Should I:

   • Modify the Teensy iMXRT1062 driver or Due
   • Use the STM32H7 driver as a base / looks like we need to brick the arduino to use CubeIDE, i dont want to brick my boards
   • Start completely from scratch?

2. Pin mapping
   For Arduino Giga, maybe we can reuse the Arduino Due's pin assignments? it quite complete, there's ramps and whatnot there.
   For the portenta however, maybe using the hat carrier, i have the hat carrier. it has ethernet as well

3. Step-by-step workflow
   What's the simplest path to a basic working driver?

based on my current understanding, the checklist are:

• Create repository with grblHAL core submodule
• making some driver somehow
• Test step pulse output with oscilloscope
• Add limit switch handling
• adding plugins
  CMIIW

I'd appreciate any advice, especially concrete examples or simple explanations since I'm new to driver development!

[terjeio]

I assume you want to use the Arduino framework for some of the complex functionality like USB...

Most of the current H7 driver is "bare metal" and might be easy to port over depending on the Arduino framework - are they using the ST CMSIS definitions for the peripherals? If not you may still start with with the H7 driver and comment out code that fails to compile.

My first step when adding a driver is to get a serial port up and running so I can communicate with the driver. Then add basic I/O - step generation, control and limit inputs and coolant control. Then PWM spindle(s) followed by USB comms etc.

But then why not contribute to the existing H7 driver instead? The firmware can be generated with the Web Builder and it might be possible to flash it via the Arduino programmer whatever that is. Do the boards come with a proprietary bootloader or do they use one of the ROM based alternatives?