STM32 Flashing

General

The Nucleos often ship with very old ST-Link Firmware. If the flash operation fails for some reason, it is possible that the embedded ST-Link firmware is either too old or has bugs that have been fixed in the meantime. You can find updates for the ST-Link on this STM webpage. You can also use the STM32CubeProgrammer software to update the firmware.

Flashing the Board Using OpenOCD

The ST Nucleo32, 64 and 144 boards include an on-board ST-LINK programmer and can be flashed using OpenOCD (use version 0.11.0 at least). OpenOCD is the standard programmer for all Nucleo boards, so no explicit PROGRAMMER environment variable has to be set.

To flash this board, just use the following command (replace the xxxxx with your Nucleo variant):

make BOARD=nucleo-xxxxx flash -C examples/basic/hello-world

If your board does not have OpenOCD set as the default programmer, you can select it by explicitly setting the PROGRAMMER variable:

make BOARD=xxxxx PROGARMMER=openocd flash

Note

The OpenOCD release cycle is quite slow and newly released chips might not be supported by the latest release. For example the STM32C0 series is not yet supported by OpenOCD 0.12.0, resulting in the following error message: Warn : Cannot identify target as an STM32G0/G4/L4/L4+/L5/U5/WB/WL family device..

Furthermore, some distributions ship even older versions, which might not have support for new devices or for the ST-Link V3 that is built-in on new generation Nucleos, resulting in a diffuse LibUSB error message such as this: Error: libusb_open() failed with LIBUSB_ERROR_ACCESS. If you have a recent OpenOCD version, you can check if your user is in the dialout and/or plugdev group and therefore has the appropriate access rights.

In either of the first two cases you have to compile the latest OpenOCD sources for your system and manually update the /etc/udev/rules.d/60-openocd.rules file with the file provided in the contrib subfolder of the OpenOCD repository. Please refer to the OpenOCD documentation for further information.

Flashing the Board Using the ST-LINK Mass Storage Device

Note

This method does not (easily) work with WSL, as the standard kernel provided does not support Mass Storage Devices. While you can access the MSD through e.g. /mnt/d/ if the ST-Link is mounted under Windows, you can not use the VCP (Virtual COM Port) via usbipd inside of WSL at the same time.

The on-board ST-Link programmer found on all Nucleo32, 64 and 144 boards will show up as a mass storage device when plugged in via USB. Copying a HEX file to the mass storage device will trigger the flashing sequence of the ST-Link. This can either be done manually or with the cpy2remed (copy to removable media) PROGRAMMER script. To use this programmer, you can use the following command:

make BOARD=nucleo-xxxx PROGRAMMER=cpy2remed flash

Flashing the Board using stm32flash

It is possible to automatically boot the STM32 board into the in-ROM bootloader that stm32flash communicates with for flashing by connecting the RST pin to DTR and the BOOT pin (or BOOT0 for STM32 MCU families with BOOT0 and BOOT1 pins) to RTS of the TTL adapter. In addition, set STM32FLASH_RESET to 1 via environment or command line to actually issue a reset with BOOT (or BOOT0) pulled high prior flashing to enter the bootloader, and a second reset with BOOT (or BOOT0) pulled low to reboot into the application. STM32FLASH_RESET defaults to 0 as of know, as with PROGRAMMER=stm32flash STM32FLASH_RESET=1 additional terminal flags are set, so that make term doesn’t accidentally keep the reset signal pulled low or boots the board into the bootloader.

make BOARD=xxxx PROGRAMMER=stm32flash STM32FLASH_RESET=1 flash

The TTL adapter this was tested with had inverted RTS and DTR signal. By setting STM32FLASH_RESET_INVERT to 1 RIOT will assume RTS and DTR signals to be inverted, by setting it to 0 non-inverted signals will be generated. As of now, STM32FLASH_RESET_INVERT is by default 1. This may change if it becomes evident that non-inverted TTL adapters are in fact more common than inverted adapters.