Cyclone® V Hard Processor System Technical Reference Manual

ID 683126
Date 8/28/2023
Public
Document Table of Contents

26.3.3. DMA Mode

The CAN controller can issue DMA controller requests to transfer data between one or both of the message interface registers and system memory. The CAN controller has two DMA request interfaces, called can_if1dma and can_if2dma. The CAN peripheral request interfaces are shared with the FPGA DMA peripheral request interfaces. To use the DMA peripheral request interface, the host processor must access the CAN control register (CCTRL) in the protocol group (protogrp). The peripheral request interface is selected through the system manager.

To activate the DMA support feature and initiate a transfer, write a 1 to the DMAactive bit in the appropriate IF command register (IFxCMR) in the message interface group (msgifgrp). After the message object transfer is completed, the CAN controller issues a DMA peripheral request to perform the next message object transfer. The request remains active until the first read or write to the message interface register.