The LPD DMA controller has eight DMA channels. Each channel is divided into two functional sides (in simple DMA mode) or two queues (in scatter-gather DMA mode), source (read) and destination (write).
The schematic in the following figure illustrates the source and destination side scatter-gather mode buffer descriptor arrays. The buffer descriptors (DSCR) point to their respective buffers. The DMA facilitates transfer of data from source (SRC) buffers to destination (DST) buffers. A source side descriptor can go to multiple destination side descriptors.
Figure 1. SRC and DST Descriptors Pointing to Data Buffers
