DMA Operation

The DMA Controller core operates in four modes, which are memory mode, direct mode, normalscatter-gather mode, and scatter-gather mode with custom descriptor list. You can choose the operation mode based on your application scenario. The scatter-gather and memory mode are disabled by default. You need to enable it before using this mode.

Transfer information like source address, destination address, channel selection, port selection, and byte of transfer are programmed through the APB3 interface. Status information, such as the BUSY state or progress of a transfer, can be retrieved through the same interface. Although each channel can have an input port or an output port, both ports cannot work in parallel due to the channel operation only allows it either in a read or a write operation. When programmed as a read operation, the DMA controller retrieves data from the main memory and outputs to AXI4-stream output interface. The AXI4-stream input interface is idle during the read operation.