Arduino for STM32

... Also you're ISR isn't as fast as it can be. This 10 bit shift needs time. You can use digitalReadFast(digitalPinToPinName(pin)); and set optimization to fastest (-O3) if ( GPIOB->IDR & GPIO_IDR_ID10 ) receiver_input1_previous = no Would obviate 10 bit shift (at execution time), but I doubt ...

I don't know what you expect timecnt to be. If you are trying to determine how long the Serial.println(receiver_input1) takes, then you should have just set timecnt = micros(), not timecnt = micros()-timecnt initially. You probably should have declared receiver_input1 as volatile too, but that shoul...

I'm not familiar with the internals of this. Maybe there is some clue in the actual values in XFerOptions or Mode when it fails, or perhaps there is some subtle difference between what you do in your code compared to the example. If it is somehow related to the rate, or just the number of times, per...

You're way ahead of me. What makes you think this has anything to do with I2C getting stuck in busy state? When I had that problem, the busy state caused a HAL error code to be generated (after some timeout). I don't remember the details now, and I also don't know how that would surface when using S...

I have done some reading around and have found that some people have had problems with the HAL I2C library and the I2C BUSY state in particular, it looks as though it is present in some STM32 erattas too. I found these results by searching "hal i2c busy eratta" into google. https://electr...

In my travels through RM008 and AN2604 yesterday, I noticed that you can get it to output RTC clock divided by 64 on the "TAMPER" pin (PC13?). If that pin is available, you would not need a very accurate counter to see if the frequency is out by as much as it appears to be.

... You say I can compensate for an LSE error in software, but I can't find that in the datasheet. it's a bit hard to find this info if you don't know exactly what to look for. Do you have any clues as to what function or register(s) I need to use? I have never tried to use the RTC on any STM32, so...

I'm guessing the problem is more likely to be on the SPI because of the shared pins. Do you have any way to check what is happening on the SPI pins, to see if there is any obvious difference between when the Ra-02 is connected or not connected? If not, I'm not sure what you can do other than maybe g...

Brevity may be the soul of wit, but it can be the bane of problem diagnosis. Did you check what I2C pins are used by default, and do something to override if necessary? What exactly do you mean when you say that there is a conflict between OV2640 and Ra-02? Does that mean that the OV2640 works using...

You have mentioned disconnecting/removing SB51 and SB56, but have you connected SB46 and SB52?