STM32F103: Is timer can interfere with uart?

Question

I have a simple program, which receives data from UART interface and driving WS2812b led strip. So, I'm using USART3 to receive data (in IRQ mode) and T3C2 (timer 3, channel 2) to drive LEDs. Here is the code: https://hastebin.com/rucumovero.cpp

If I'm using uart interface without enabling a timer - everything works just perfect, but when I enable it - I'm start losing data. for example, here the log if I send 5 similar 32 byte packets [0x41..0x60]

read 29 byte(s): 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 
read 29 byte(s): 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 60 
read 28 byte(s): 41 42 43 44 45 46 47 48 49 4A 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 5D 5E 5F 60 
read 29 byte(s): 41 42 43 44 45 46 47 48 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 5A 5B 5C 5D 5E 5F 60

every time 3~4 bytes are lost.

I tried to use different baud rate, different usart port - the result is the same. There is setting timer interval at line 142:

timer_set_period(TIM3, WSP);

where

#define TICK_NS (1000/72)
#define WSP (1300 / TICK_NS)

If I will comment this line - problem will disappear, but, of course, I won't be able to drive LEDs without it.

So, it looks like I can't drive WS2812b leds and receive data from UART at the same time. Is it suppose to behave like this? Any idea how can i fix it? Thank you very much!

Answer 1

看来是定时器的中断影响了串口接收中断。

Answer 2

请检查串行中断优先级是否高于其他优先级。