My approach to support STM32H503RB on NUCLEO-H503RB

[wjklimek1]

Hi,
I noticed that STM32 H5 recently got support from TinyUSB and I was disappointed that STM32H503 line was sadly not included in this release. But TinyUSB being an open source project gives me opportunity to change it and I want to ask your opinion on my approach.

STM32H503 differs slightly from STM32H563 and STM32H573. Code in hw/bsp/stm32h5/family.c was written with only former two in mind. I made following changes to make all these boards coexist peacefully:

Make GPIO clock enabling dependent on board

In respective board.h files I changed clock setup function name from SystemClock_Config() to board_clock_init() and I moved all __HAL_RCC_GPIOx_CLK_ENABLE calls to this function. It is necessary to make GPIO clocks dependent on board because H503 line does not have some of GPIO ports that are required by H563/H573. It is done in a similar way in F4 family.

Make call to HAL_PWREx_EnableVddUSB() dependent on board

Similarly to GPIO ports, H503 does not utilize PWR->USBSCR register. USB peripheral is on by default. So I wrapped call to HAL_PWREx_EnableVddUSB() in a function board_enable_vdd_usb(). In board.h files for H563/H573 it calls HAL_PWREx_EnableVddUSB():

static  inline  void  board_enable_vdd_usb(void)
{
/* Enable VDDUSB to power on USB peripheral */
HAL_PWREx_EnableVddUSB();
}

In H503 it is left empty:

static  inline  void  board_enable_vdd_usb(void)
{
// USB in STM32H503RB does not require enabling VDD
}

Again, it is done in a similar way in F4 family to handle VBUS detection.

Redefine USB_DRD_BASE to USB_DRD_FS_BASE

For some reason equivalent of USB_DRD_BASE definition from stm32h563xx.h is defined as USB_DRD_FS_BASE for stm32h503xx.h. Nevertheless, they point to the same peripheral address USB_DRD_BASE_NS. To work around this I took following approach: in the file dcd_stm32_fsdev.h i check if STM32H503xx is defined and if it is, I redefine USB_DRD_BASE as USB_DRD_FS_BASE.

#elif CFG_TUSB_MCU == OPT_MCU_STM32H5
	#include "stm32h5xx.h"
	#define FSDEV_BUS_32BIT
	#define FSDEV_BUS_32BIT

	#ifdef STM32H503xx
	#define USB_DRD_BASE USB_DRD_FS_BASE

	#define FSDEV_PMA_SIZE (2048u)
	#define FSDEV_PMA_SIZE (2048u)
	#undef USB_PMAADDR
	#undef USB_PMAADDR

Normal implementation of H503RB-NUCLEO board support files

I created directory for stm32h503nucleo and added modified board.cmake,board.mk and board.h files. The only notable changes are GPIO and UART definitions and clock configuration specific for H503RB-NUCLEO.

Result

I was able to successfully compile code for all 3 boards and I tested dcd_msc and cdc_dual_ports examples on H503RB-NUCLEO. However, I don't have proper hardware to test other two boards.

Discussion

Before I create pull request I want to know your opinion on these changes. I am mostly concerned about USB_DRD_BASE redefinition. It works fine for now, but is it "clean", proper way of doing things?
You can preview my changes on TinyUSB fork here:
master...wjklimek1:tinyusb:master

[HiFiPhile]

Thanks for your interest of TinyUSB, your changes looks good.

I can test with a H573-DK, I think we are get it merged with minor style format.

[wjklimek1]

Hi, thanks for your reply. I will open a pull request then. Let me know if I and where I should change formatting.

BTW, you are doing great work with TinyUSB, I really appreciate your commitment.

[wjklimek1]

After some minor changes we managed to merge H503 support into master. Thanks again for everyone involved, it's nice to have it officially supported.