Arduino for STM32

i'm a big fan of those little beasts: stm8s003 and stm32f030. but the 8s has limited utility as an arduino clone - as the space is quite limited, especially if you compile with a free compiler. under iar, they work wonders.

i would first make sure that the hardware works - the right crystal is used, and the LSE oscillates in run mode correctly, ... I would then try to find out if the code is wrong -> it would be unthinkable if this is a (chip) hardware problem. all else fails, I would try to correct the problem. the si...

unless you are using something truly bad, those crystals are spec'd to 20ppm and usually within 5ppm. so 5% is a little extraordinary. I would first verify the cause. if it is indeed in the crystal, the hardware does allow LSE compensation - look to the reference manual. but unlikely to the extent o...

stm32f1

those chips have DWT and you can get timing resolution down to ns -> at 72Mhz, you get 13.9ns

GPIO_Init (an STM8-specific API function) to actually enable interrupts for a particular pin.

or you can set the CR2 bits. CR1 bits enable pull-up.

I know all the registers to use, I get bit arithmetics, but what is the syntax?

it might be simpler to just check the 1k-page reference manual. most of those bits are in CCER but there should be a section on the right bits for all of that.

beats out going through the HAL functions.

Bare Metal is the closest you can get to the processor,

you can always code assembly. or even hand-generate binary.

A potential problem about Bare Metal is how portable your code will be.

I usually code to cmsis. it has the most portability.

result

you will notice that your reading changes a little bit, partly because of the sequence of reading the timer can differ based on if you are trying to read the leading edge or the trailing edge.

one way to do that is to always read the timer first in the isr

analogwrite() produces a digital output whose duty cycle carries the analog information.

what you observed is expected.

most of the code you find will be developed against CMSIS and a set of vendor header files. so I would encourage you to at least try to align there.