Arduino for STM32

Try a simple 1Hz blink in the loop, no serials or USB or tricky stuff. That will show if the loop is running and the clock frequency. As for clocks, look in the variant.cpp file corresponding to your selected core/board/variant, its quite easy to see what clock and frequency is selected. If you boar...

Looking at the, not very complete, documentation pictures a https://www.biqu.equipment/products/bigtreetech-skr-pro-v1-1-32-bit-control-board?variant=29207358865506, there seems to be a swd debug port/pinheader just behind the USB connector. Should be useable to upload with the STLink. I also think ...

Setting up the clock for 10MHz external osc and 80 MHz working frequency is simple /* Configure 10MHz external TCO as system clock source * Make sure to #define HSE_VALUE 10000000 */ void InitHSE() { RCC_OscInitTypeDef RCC_OscInitStruct = {}; RCC_ClkInitTypeDef RCC_ClkInitStruct = {}; /* Reset to MS...

I am playing with similar ideas, but I am using the Nucleo L432 board. Nice thing is that there is no onboard high frequency crystal so the OSC input is exposed and ready to use. This makes it possible to drive the MCU with the output from the disciplined osc, simplifying the timing.

Just a comment, nowhere in the previous posts did you mention the call to HAL_SAI_Receive() inside the timer callback. How do you expect folks to give sensible help??? As far as I know the serial port drivers dont use any hardware timers. It might be some other code running that has not been mention...

What processor is this ?
How do you measure the actual timer overflow frequency ?
Whats the value of SystemCoreClock ?

I would try something like a single shot pwm pulse with 150us width, then you can set the interrupts at the end of this pulse if needed

A very common reason for connection problems under Linux is that the Modem Manager connects to the serial port automagically and blocks access from other applications. I dont have such a system set up for testing at the moment so cannot help much more, but I remember that I have previously uninstall...

Variants of STM32F412Vx with 100 pins or less dont have ports F and G according to datasheet, still GPIOF_BASE and GPIOG_BASE are defined in the stm32f412vx.h header file. Since PortNames.c only checks if GPIOF_BASE is defined that will fail since __HAL_RCC_GPIOF_CLK_ENABLE() is not defined, see &qu...

If you look in variant.cpp for this board at line 161, PF_10 is entered before PF_9 into the digtalPin[] array. On the other hand in variant.h PF9 is declared before PF10, and after that LED_D1 and LED_D2 are declared as PF9 and PF10. So the end effect is that LED_D1 = PF9 = 94 maps to digitalPin[94...