SSP DMA problems

Started by tamirmichael January 28, 2011

My SSP controller is configured to use the GPDMA of a LPC2478 to deliver data to external RAM. The SSP's hardware buffer is 8 bytes (fixed), and the DMA's transfer size if 8 frames (8 bit wide), and it is programmed to generate an interrupt once finished. It does and I can see the first 8 bytes of the data that arrived at the SSP in RAM, but not the rest! The SSP receives data in multiples of 8. In other words: I get one DMA interrupt, acknowledge it but no other interrupts arrive. I do reconfigure the channel (1) and clear the halt bit inside the DMA ISR. Can somebody offer me an explanation/solace...?

An Engineer's Guide to the LPC2100 Series