How to Create Circular (Ring) buffer from UART using DMA?

Hello Sayed

Did you check the Ping-Pong example in TIVAWare

C:\ti\TivaWare_C_Series-2.1.0.12573\examples\boards\ek-tm4c123gxl\udma_demo

Regards

Amit

I have done it successfully using the ping-pong mode on TM4C1294NCPDT.

char buffer[BUFFERS][TRANSFERSIZE];

When you call uDMAChannelTransferSet you loop through the buffers and the DMA controller will fill the buffer in a circular fashion. Using uDMAChannelSizeGet you can figure out where the DMA controller is currently writing to. You have to check for buffer overflow when you reset a channel to make sure you're writing over data before you have read it.

This lets you create a buffer that is larger than would otherwise be permitted in strict ping-pong mode.