Nios II Classic Software Developer’s Handbook

ID 683282
Date 5/14/2015
Public
Document Table of Contents

6.11.2.1. Memory-to-Memory DMA Transactions

#include <stdio.h> #include <stdlib.h> #include "sys/alt_dma.h" #include "system.h" static volatile int rx_done = 0; /* * Callback function that obtains notification that the data * is received.*/ static void done (void* handle, void* data) { rx_done++; } /* * */ int main (int argc, char* argv[], char* envp[]) { int rc; alt_dma_txchan txchan; alt_dma_rxchan rxchan; void* tx_data = (void*) 0x901000; /* pointer to data to send */ void* rx_buffer = (void*) 0x902000; /* pointer to rx buffer */ /* Create the transmit channel */ if ((txchan = alt_dma_txchan_open("/dev/dma_0")) == NULL) { printf ("Failed to open transmit channel\n"); exit (1); } /* Create the receive channel */ if ((rxchan = alt_dma_rxchan_open("/dev/dma_0")) == NULL) { printf ("Failed to open receive channel\n"); exit (1); } /* Post the transmit request */ if ((rc = alt_dma_txchan_send (txchan, tx_data, 128, NULL, Null)) < 0) { printf ("Failed to post transmit request, reason = %i\n", rc); exit (1); } /* Post the receive request */ if ((rc = alt_dma_rxchan_prepare (rxchan, rx_buffer, 128, done, NULL}} < 0) { printf ("Failed to post read request, reason = %i\n", rc); exit (1); } /* wait for transfer to complete */ while (!rx_done); printf ("Transfer successful!\n"); return 0; }