here is my codes. I want to verify the result and display at the end, however I got like "cdcd", what's wrong? thanks
/* * "Hello World" example. * * This example prints 'Hello from Nios II' to the STDOUT stream. It runs on * the Nios II 'standard', 'full_featured', 'fast', and 'low_cost' example * designs. It runs with or without the MicroC/OS-II RTOS and requires a STDOUT * device in your system's hardware. * The memory footprint of this hosted application is ~69 kbytes by default * using the standard reference design. * * For a reduced footprint version of this template, and an explanation of how * to reduce the memory footprint for a given application, see the * "small_hello_world" template. * */
#include #include #include #include "system.h"
static volatile int rx_done = 0;
/*
- Callback function that obtains notification that the data has
- been received.
*/ static void done (void* handle, void* data) { rx_done++; }
int main(int argc, char* argv[], char* envp[]) { int rc; static char buff[256]="abcdefghijklmn\0"; alt_dma_txchan txchan; alt_dma_rxchan rxchan;
void* tx_data = (void*) buff; /* pointer to data to send */ void* rx_buffer = (void*) 0x01000000; /* on_chip_memory addr*/
/* 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"); printf ("%s",(ONCHIP_MEMORY_0_BASE)); return 0; }