DMA

The DMA is one of the most critical elements of any FPGA or high speed computing design. It allows data to be transferred from source to memory, and memory to consumer, in the most efficient manner and with minimal intervention from the processor. It’s no wonder then that a tutorial I wrote three years ago about using the AXI DMA IP, is still relevant and still getting thousands of visits per month. I decided to remake that tutorial, this time as a video and using Vivado 2017.2 (just today they released Vivado 2017.3, doh!). Although I prefer doing written tutorials, I think that video tutorials can be very useful in their own way, and they’re a hell of a lot easier for me to produce. I hope you find this one useful.

Update 2017-10-10: I’ve turned this tutorial into a video here for Vivado 2017.2. In a previous tutorial I went through how to use the AXI DMA Engine in EDK, now I’ll show you how to use the AXI DMA in Vivado. We’ll create the hardware design in Vivado, then write a software application in the Xilinx SDK and test it on the MicroZed board (source code is shared on Github for the MicroZed and the ZedBoard, see links at the bottom).

Update 2014-08-06: This tutorial is now available in a Vivado version - Using the AXI DMA in Vivado

One of the essential devices for maximizing performance in FPGA designs is the DMA Engine. DMA stands for Direct Memory Access and a DMA engine allows you to transfer data from one part of your system to another. The simplest usage of a DMA would be to transfer data from one part of the memory to another, however a DMA engine can be used to transfer data from any data producer (eg. an ADC) to a memory, or from a memory to any data consumer (eg. a DAC). In older systems, the processor would handle all data transfers between memories and devices. As the complexity and speed of systems increased over time, this method obviously was not sustainable. DMA was invented to remove the bottleneck and free up the processor from having to deal with transferring data from one place to another. In high performance digital and FPGA systems, the data throughput is typically way too high for the processor to deal with, so a DMA is essential.