STM32F412Cx USART3 contradiction between CMSIS and HAL

[sgauche]

CircuitPython version

Adafruit CircuitPython commit 9b32d549, Custom board with STM32F412CG

Code/REPL

None

Behavior

I am adding a board to CircuitPython with a STM32F412CG micro on the board. I ran into an error while building CircuitPython about USART3 functions:

common-hal/busio/UART.c: In function 'uart_clock_enable':
common-hal/busio/UART.c:484:9: error: implicit declaration of function '__HAL_RCC_USART3_FORCE_RESET' [-Werror=implicit-function-declaration]
484 | __HAL_RCC_USART3_FORCE_RESET();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
common-hal/busio/UART.c:484:9: error: nested extern declaration of '__HAL_RCC_USART3_FORCE_RESET' [-Werror=nested-externs]
common-hal/busio/UART.c:485:9: error: implicit declaration of function '__HAL_RCC_USART3_RELEASE_RESET' [-Werror=implicit-function-declaration]
485 | __HAL_RCC_USART3_RELEASE_RESET();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
common-hal/busio/UART.c:485:9: error: nested extern declaration of '__HAL_RCC_USART3_RELEASE_RESET' [-Werror=nested-externs]
common-hal/busio/UART.c:486:9: error: implicit declaration of function '__HAL_RCC_USART3_CLK_ENABLE' [-Werror=implicit-function-declaration]
486 | __HAL_RCC_USART3_CLK_ENABLE();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
common-hal/busio/UART.c:486:9: error: nested extern declaration of '__HAL_RCC_USART3_CLK_ENABLE' [-Werror=nested-extern
]
common-hal/busio/UART.c: In function 'uart_clock_disable':
common-hal/busio/UART.c:559:9: error: implicit declaration of function '__HAL_RCC_USART3_CLK_DISABLE' [-Werror=implicit-function-declaration]
559 | __HAL_RCC_USART3_CLK_DISABLE();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
common-hal/busio/UART.c:559:9: error: nested extern declaration of '__HAL_RCC_USART3_CLK_DISABLE' [-Werror=nested-externs]

Description

See STMicroelectronics/STM32CubeF4#42

In CMSIS/Device/ST/STM32F4xx/Include/stm32f412cx USART3_BASE is defined.

In STM32F4xx_HAL_Driver/Inc/stm32f4xx_hal_rcc_ex.h, USART3 functions are not defined for STM32F412Cx.

https://github.com/hathach/st_driver/blob/1900834751fd6754457874b8c971690bab33e0a7/STM32F4xx_HAL_Driver/Inc/stm32f4xx_hal_rcc_ex.h#L4972-L4973

So that causes issues when common-hal/busio/UART.c sees USART3 as defined but can't find the functions for USART3.

The fix ST applied to their repo was to remove all of the #ifdef's for all USART3 define's in stm32f4xx_hal_rcc_ex.h. USART3 is available on the STM32F412CG, but only as half-duplex. See Table 2 note 2 in the STM32F412CG datasheet.

Additional information

No response

[tannewt]

Thanks for the issue! Is the best fix to switch to the STM repo for st_driver? Would you mind making a PR for it?

[sgauche]

@tannewt
I was able to build successfully by only updating the stm32f4xx_hal_rcc_ex.h file to the latest from ST's repo.

I noticed that circuitpython has an archived repo as a submodule I think for the ST drivers. Are archived repo's able to be modified? This is the archived repo: https://github.com/hathach/st_driver

I'm not familiar enough with circuitpython yet to say whether it would be feasible to update to ST's latest release... There must have been a reason to point to an archived repo? Although it would be a nice update, it looks like most of the ST stuff in circuitpython is >2 years old.

I've seen @hathach 's name around here, maybe he would have some input on that?

[tannewt]

It looks like TinyUSB switch to direct submodules to the ST repos: hathach/tinyusb#544

[hathach]

Yeah, we should switch to official st repo which is only available recently. The st_driver repo is created way before that.

[sgauche]

I opened a PR to make this change #5976

[sgauche]

PR #5976 was merged which fixes this issue.