On a LPC4078 I'm using 2 channels of DMA to send and receive through a SPI connection (SSP peripheral) and have send on channel 0 and receive on channel 1. I start the DMA on channel 0 first. Channel 0 has higher priority than channel 1. Both send and receive are 14 bytes of data.
I get channel 1 DMA complete interrupt first and I was xpecting to get channel 0 complete interrupt first.
It appears as though the send happens first and then the receive ie they are half duplex, which I am quite happy about.