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MaaXBoard-RT: support, forum - VCP UART for you

tjaekel

After working on and using Arduino Portenta H7 and Teensy 4.1 - I am starting to work on AVNET MaaXBoard-RT board.
I have realized: forum (and support) is not very lively (for this -RT board).

Let's see:
Maybe, I can provide some help and support when working on this board.

Intentions:

I will port (convert) my project (a network SPI adapter, with GPIO INT handling, Pico-C as scripting engine, use it from host Python scripts,
used/needed for my (professional) office work).

Changing to MaaXBoard-RT is mainly caused by the performance and feature requirements I need:
more internal RAM (2MB), faster MCU (1GHz), faster external flash (8bit lane Hyperflash, 300 Mbps (?)), faster ETH (1Gbps) and
especially: a real HW debugger supported.
(I am not a big fan of the Arduino SW environment/IDE/LIB, their forums and how to get help there for my daily job).

Status

The AVNET "out-of-the-box" demo project 'GUI-Guider-Demo' is working, can be flashed and runs.
Find it here:

https://github.com/Avnet/MaaXBoard-RT-V3--Projects

Just: the AVNET user manual is a bit outdated: the file "board.h" should be the latest one (but it is in this GitHub project or in project below).
And the patching for this Flash Loader file was a bit tricky: I think you have to copy also in a sub-folder in your workspace (see the error messages when it fails).

So, the IDE works, the AVNET demo project works, the board works (flash loader and debugger).

Use SDK demos

I was able to compile, flash and run the EVK MIMXRT1070 CDC project:
just check carefully the documented differences and what to adapt.
This project was working almost without any changes (just patch the files and flash loader).

I need USB-C VCP UART.
(I want to get rid of the LPUART connected to debugger or USB-UART-dongle)
This project demonstrates how to have a FW which enables the USB-C device with a CDC class, for a USB VCP UART.
It works.
Just USB-C for power and UART.

Find my project here:

tjaekel/MaaXBoard-RT_cdc_vcom_freertos_cm7: MaaXBoard-RT VCP UART example (github.com)

MaaXBoard-RT with USB VCP UART

I have modified and extended this project:
instead of polling, if USB UART has received anything, I have added a FreeRTOS event.
This event is sent from the USB stack, when something was received, to release the App Task, now in blocking mode.

Not just one single USB-C to a host - the USB VCP UART is also way faster (as the debug UART).

Let's see how it goes with my project on MaaXBoard-RT.
Maybe, we will see us here more often.

  • Strange is just:

    I cannot send anything, even USB should be established (MCU runs, UART terminal (TeraTerm) finds USB VCP UART).
    I have to send any character first, to get the FW progressing (to "connect really").

    Not sure, if this is an USB VCP UART spec. issue or a code issue in my FW.

    I have also realized:
    If I do not send anything, after something was received - the next receive (e.g. for any key press) does not work.
    It looks right now as a "ping-ping" (handshake) issue:
    Before you can send - you have to receive anything.
    You cannot receive when nothing was send before.
    (always as "receive -- send - receive - ...")

    (looks more like a code issue, the state machine gets into a "deadlock"....? when not sending anything anymore...?)

    If you want to watch my progress - here is my GitHub project, using the latest USB VCP UART (for a command line):

    tjaekel/MaaXBoard-RT_SPIder: MaaXBoard-RT SPIder framework (github.com)

    Have fun with the MaaXBoard-RT (a great one).