Posted on January 15, 2018 at 11:00
Hello!
I am using RX DMA with RX timeout detection (based on Efficiently receive UART data using DMA). Under normal condition, everything works fine, but I have problems with the error handing. My MCU is the F302R8 on the NUCLEO-F302R8.
I have I test case, where I send data on the half baudrate to provoke an UART framing error on the receiver. For example, I send “0xF8, 0x00, 0xFF�? and the receiver gets “0x80, 0x00 (framing error) 0x0FE�?
Now I have two problems:
First problem: DDRE (DMA Disable on Reception Error) does not disable the DMA.
If USART_CR3_DDRE is disabled, I receive only the error free bytes ''0x80, 0x0FE''. This is as expected.But if USART_CR3_DDRE is enabled I receive “0x80, 0x00, 0x0FE�? and the DMA is not stopped.Here I would expect to receive only the bytes until the error and that the DMA is disabled.Second problem: My test sometimes cause a UART Timeout and sometimes not.
Strangely if the UART error interrupt is enabled, then the UART Timeout is set after each block of bytes. (In the ISR I only increasing a counter and clear the framing error.)Without UART error interrupt not each block of bytes causes a UART Timeout.
