Arduino for STM32

I don't understand how the CPU can put the new byte in to the buffer faster

From hardware point of view, it is possible to prepare next byte while harware is currently sending the previous one, there is a mechanism of shadow/shift register.

As I said, parity if working fine, and I checked register everything is good. Then about Stop which is lager than expected: Register are properly configured, but the gap is due to the current implementation of write operation. Characters are send 1 by 1 on UART. It means we wait for 1st Byte complet...

The extra bit is the stop which last 104us, as if Stop is 2 bits instead of one

Hi @TadyTheFish , I tested on my side and parity works fine on BluePill. Looking at your screenshoot, everything looks normal for me: You select 8E1, this means you want an Even parity bit, so length of a frame is: Start+ 8 data + 1 parity + Stop Try with 0x69 (for test purpose) instead of 0x68 thus...

Hi @Bambo , With fpiSTM, we spent some time on your issue and here is our conclusion: We tested both Arduino SD library and SdFat.h. Our results are quite stable around 13000 with core V1.8.0 (whatever library) And around 14000 when we take some recent improvement https://github.com/stm32duino/Ardui...

According to LwIP documentation, https://github.com/stm32duino/LwIP/blob/master/src/core/pbuf.c * So, a packet queue consists of one or more pbuf chains, each of * which consist of one or more pbufs. CURRENTLY, PACKET QUEUES ARE * NOT SUPPORTED!!! Use helper structs to queue multiple packets. So my ...

Code in callback is executed in interruption context.
So yes, when timer1Interrupt() executes it will block more than 4 seconds(due to your delay).
So during this time it prevent timer2Interrupt() from running.
Generally, callback should be very short, delay and print are not recommended.

Concerning issue with GPIO, I found a limitation in Servo.h that limit internal pin number used to 0..63. But in your case, pin number PA0 is 103 and thus out of range. I proposed a patch to extended usable pin number to 255. See Pull Request: https://github.com/stm32duino/Arduino_Core_STM32/pull/88...

It is not possible to add new timer for Servo:
It is right that generic Arduino header ServoTimers.h allow to define several timers instructure timer16_Sequence_t.
But stm32duino implementation is designed for only 1 timer for servo.

I agree with fpiSTM, also take care with frequency measurement:
if input frequency is too high, you may send most of your time in interrupt callbacks