Changing the source address during the eDMA transmission process

[Jiuer]

Hello NXP Community,

I would like to ask if, after the eDMA channel configuration is completed, it is possible to change the source address after the transmission is completed once. Currently, I am using eDMA to transfer a large amount of data to the DAC output. However, the signal to be output does not have a periodicity, and after the current eDMA output is completed, the output value needs to be changed. Essentially, it requires changing the source address. So, does eDMA have a function that enables the source address to be updated after the DMA transfer is completed?

Best Regards,

Jiuer

[Alice_Yang]

Hello @Jiuer 

Yes, eDMA supports changing the source address. You can utilize the scatter/gather function to do this.

Scatter/gather is the process of automatically loading a new TCD into a channel. It allows a DMA channel to use multiple TCDs; this enables a DMA channel to scatter the DMA data to multiple destinations or gather it from multiple sources. When scatter/gather is enabled and the channel has finished its major loop, a new TCD is fetched from system memory and loaded into that channel’s descriptor location in the eDMA programmer’s model, thus replacing the current descriptor.

Detail please refer to chip reference manual. And there is scatter-gather demo under SDK, you can refer to.

BR

Alice