T2080 UARTs CPU Offload

[jameshorton]

I’m looking for ways to offload CPU of getting my serial data at high baud rates.

I believe there's already a DMA taking place within the SOC to get the data to the 16 byte FIFO which I'm currently polling. We are using the polling mode. Can DMA be also setup to move the data from the 16 byte FIFO into local DDR? The sender is at a high baud rate and sends bursts greater than 16 bytes so we have to have a single core dedicated to polling this right now.  

Jim

[ufedor]

The design team response:

"Term DMA mode was used to describe the two kinds of operations supported by DUART.
1) Non-DMA kind of operation where software writes one byte at a time in UTHR register and once it is transmitted the software writes the next byte
2) DMA kind of operation where software or an external DMA fill the inbuilt FIFO, when FIFO is full, DUART initiate the transmission.

T2080 doesn't support the DMA kind of operation."

[jameshorton]

Thank you for that fast response and clarification.  The RM makes it sounds like you can can't use the external DMA to push data into the TX FIFO. 

It just doesn't seem clear "to me" that you can or absolutely can NOT use DMA to read data out of the UART RX FIFO. My T2080 UARTs are simply receivers of data in this use case.  The data comes fast so I have to have my CPU give a great deal of attention to the UART RX FIFOs.