K64 eDMA UART missing bytes

nbuters — Thu, 09 Nov 2017 08:41:09 GMT

I'm trying to use the eDMA UART module on a Kinetis K64. Code has been based on the example from the SDK.

Everything works ok during normal operation, but when a bad packet is received (eg. frame error) the Kinetis stops receiving and the eDMA receive operation never completes.

I would like to be able to recover from errors (parity, framing, noise, etc) by discarding the data in the buffer and starting a new receive operation. I've written some code to check status flags for errors and start a new receive operation when an error is detected;

uint32_t active_flags = UART_GetStatusFlags(p_base);
uint32_t error_flags = kUART_NoiseErrorFlag | kUART_FramingErrorFlag | kUART_ParityErrorFlag;
if (active_flags & error_flags)
{
UART_TransferAbortReceiveEDMA(p_base, &uart_edma_handle);
UART_ClearStatusFlags(p_base, error_flags);

   uart_transfer_t xfer;
   xfer.dataSize = RX_BUF_SIZE;
   xfer.data = rx_buf;
   UART_ReceiveEDMA(p_base, &uart_edma_handle, &xfer);

}

This isn't working. After the receive operation is restarted the subsequent data coming in on the RX line gets missed. Calls to UART_TransferGetReceiveCountEDMA() return 0. Eventually, after a few seconds and many bytes of missed data, it starts receiving again.

Any ideas what could be causing this?

Kinetis Microcontrollers中的主题 K64 eDMA UART missing bytes

K64 eDMA UART missing bytes