Arduino for STM32

My somewhat poorly commented/structured code below Impossible to follow. I think you are trying to configure TIM1 to over flow at 8049, and then set output compare to trigger at 1 - not sure why. maybe you can help more by stating what you are trying to do - invoking DoPid() periodically? your code...

if you need 128Mhz PWM, there is something wrong with your solution, or the application of this MCU in your solution. In that case, it is much helpful for you to say "here is a problem I want to solve. what would you suggest as a solution?" if you indeed need 128Mhz PWM (for whatever reaso...

you got that right. a double-read is a must here. a few other ways to get this working: 1. using a struct + union so you can read / write individual 32-bit pieces without shifting. 2. using pointers to the write to / read from the individual 32-bit pieces as well. the code will be endian-dependent, ...

did a quick scan of the reference manual. Some unique aspects of this chip: 1. rtc clocks can only be selected once. Need to reset BDCR for each clock change. 2. rtc clock cannot be changed if LSECSSON bit is on. 3. didn't find PWR block clock enable -> didn't look too hard either. the basic flow is...

maybe you can go through the reference manual to see how to enable the rtc. generally BDCR is write-protected and you have to do something special to change its default values.

I can also confirm that the STM32 F 030 has backup registers, in the RTC domain. i can see values stored there persist from reset to reset. An undocumented feature as it is not in the datasheet. I posted a write-up on that here: https://dannyelectronics.wordpress.com/2023/12/06/stm32f030-backup-regi...

#define PB13toPU() do {REG_MOD(GPIOB->CRH, 0x08<<((13%8)*4), 0x0f<<((13%8)*4));} while (0) //set PB13 to INPUT_PULLUP 0b1000, ODR bit set separately #define PB13toPP() do {REG_MOD(GPIOB->CRH, 0x01<<((13%8)*4), 0x0f<<((13%8)*4));} while (0) //set PB13 to OUTPUT Pushpull 0b0001/0010/0011, ODR bit set...

The CNFx and MODEx bits do that. Check out the CRH...CRL registers.

A macro will be sufficient.

That means it is working. As the crystal is like a few mhz and your default oscillator likely runs at 10s of mhz.

R1 turns a NOT gate into a high gain linear amplifier. It was one of the tricks during the cmos days.

You can also think of R1 plus stray capacitance to form a RC oscillator that gets the oscillator started.