Simultaneously DMA Transfers with both channels

[noob234]

Is it possible to transfer to and from shared memory at the same time with DMA channel 0 as receiver and DMA channel 1 as sender? I modified the e_dma_copy function to make this possible (channel can now be selected) but it seems that only one direction is working at the same time.

Best regards

[notzed]

[noob234]

Thanx for the answer. Yes I also uncommented the while busy loop in e_dma_copy():

line 76: // while (e_dma_busy(chan));

But it makes no time difference whether I use only dma_0 for sending and receiving or dma_0 for sending and dma_1 for receiving data at the same time. Together with your statement that when the bus is saturated, dma_0 has priority I conclude the bus must be saturated!

Best regards

[notzed]

Oh I mis-read "shared memory" as "local". But yeah if you're going to the external memory a single dma channel will keep the link busy.

It works quite well if you're doing global<->core plus core<->other core. And it can be used for 2 separate async double-buffers without needing to use interrupts.

[noob234]

Thanx for the answer. I forgot the use for local-local dma transfers. So the second dma channel is usable for something anyway