       127
DMA Module
CHAPTER 8
The NS7520 supports 13 DMA channels. Each channel moves blocks of data between
memory and a memory peripheral. Each block transfer is defined by a descriptor of
two words (memory-to-peripheral) or three words (memory-to-memory) in circular
buffers maintained by the CPU. As each block transfer completes, the CPU need
update only the descriptor for the completed block transfer, minimizing CPU
intervention.