Document New Board Addition

[anjomro]

Is your feature request/improvement related to a problem? Please describe.

I am trying to use the core with a custom devboard that is using a STM32L051K8 chip. I followed the documented steps for adding a new variant (mainly adding clock and linker script): https://github.com/anjomro/Arduino_Core_STM32

My main problem is that i fail to get USART2 on PA2/PA3 to work. With STM32CubeIDE it works flawlessly, with the Arduino Core I don't see any output when writing out to serial.

I have seen with other boards that files like variant_boardname.h and PeripheralPins_boardnames.h are used. As far as i could see the generic files related to the L051K(6-8)U variant should be fine (> #define SERIAL_UART_INSTANCE 2, #define PIN_SERIAL_RX PA3; #define PIN_SERIAL_TX PA2) but it doesn't work nevertheless. (Or is this an issue that the Arduino core is expecting a UART device while the STM32 chip provides an USART device?)

Describe the solution you'd like

I would be very grateful for documentation on the steps necessary to add a board, similar to the documentation on how to add a new variant. Furthermore some documentation on the variant_board.h and PeripheralPins_board.h files would be marvelous, including information when they might be useful or in which cases the pre-generated generic versions are sufficient.

Describe alternatives you've considered

I would also be happy about pointers on any errors that I have made which prevent my approach from working.

Additional context

The result of following the variant addition files: https://github.com/anjomro/Arduino_Core_STM32/tree/main/variants/STM32L0xx/L051K(6-8)U

I also tried configuring a custom PeripheralPins header file based on the code comments which can be found here: https://github.com/anjomro/Arduino_Core_STM32/blob/L051K-Test/variants/STM32L0xx/L051K(6-8)U/PeripheralPins_STM32L051K.c

I would be very happy to submit a PR for a generic board/variant once it's working :)

[fpistm]

Hi @anjomro
If you follow the wiki, it should work as default Serial uses PA2/PA3 as you stated (Declare the generic in the boards.txt, add a ldscript.ld and a generic clock).
You select the right one in the Arduino IDE ? If you have the Arduino IDE2, you have to clean the cache to be able to see it in the menu.
If it does not work, maybe an issue with the clock config.