Tool/software: Linux
The issue happened in the kernel 2.6.
We have a app that communicate with DSP through UART port.
If we used reboot command to reboot reader, sometimes app failed communicate with DSP. We measured the signal on line, there is no data on the TX line, please refer to the attachment.
I checked the register when issue happened.
CSR = 0x40
CCR = 0x81093
And the TX FIFO and RX FIFO are empty.
It look like the dma began work but never finish.
I tried to reset logical channel in dma to recover it, but the dma failed again at next send.
reset logical channel steps
Clear the RX FIFO and TX FIFO
Stop dma, disable logical channel and clear dma parameters.
Set new dma parameters and start new dma operation
Our UART configuration are as following
No hardware flow control
No software flow control
Hardware synchronization
Data rate is 460,800
Now I tried to reset UART also.
