DMA

/*  * "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 <stdio.h>

int main() {   printf("Hello from Nios II!\n");

  return 0; }*/

#include "inc/sopc.h"

#include "string.h" #include <stdio.h> #include <sys/unistd.h> #include <string.h> #include <sys/alt_irq.h> #include "system.h" #include "alt_types.h" #include "inc/altera_avalon_dma_regs.h"

/*-----------------------------------------------------------------------------  *  Define  *-----------------------------------------------------------------------------*/ #define   DAT_LEN     100   #define   SRC_ADDR    (SDRAM_BASE + 0x20000) #define   DST_ADDR    (SDRAM_BASE + 0x30000)

/*-----------------------------------------------------------------------------  *  Function prototypes  *-----------------------------------------------------------------------------*/ static void DMA_Init(void);      //初始化DMA

/*-----------------------------------------------------------------------------  *  Variable  *-----------------------------------------------------------------------------*/ unsigned int dma_end_flag = 0;

/*  * ===  FUNCTION  ======================================================================  *         Name:  main  *  Description:  通过DMA,将SDRAM中一个地址中的数据传输到另一个地址  * ==== /*-----------------------------------------------------------------------------  *  Variable  *-----------------------------------------------------------------------------*/ unsigned short * ram = (unsigned short *)(SDRAM_BASE+0x10000); //SDRAM地址 unsigned short * ram_src = (unsigned short *)SRC_ADDR; unsigned short * ram_dst = (unsigned short *)DST_ADDR; /*  * ===  FUNCTION  ======================================================================  *         Name:  main  *  Description:  函数主程序  * =====================================================================================  */ int ll(void) {     int i;     printf("Hello from Nios II!\n");     memset(ram,0,100);

    //向ram中写数据，当ram写完以后，ram的地址已经变为(SDRAM_BASE+0x10100)     for(i=0;i<100;i++){         *(ram++) = i;     }

    //逆向读取ram中的数据     for(i=0;i<100;i++){         printf("%d\n",*(--ram));     }   

       

    for(i=0; i<100; i++){         *(ram_src++) = i*i;     }

    //初始化DMA     DMA_Init();     //等待中断结束，说明传输完成     while(dma_end_flag == 0);     //打印接收地址的数据     for(i=0;i<100;i++){         printf("%d\n",*(ram_dst++));     }           return 0; }

/************************************/ //DMA中断 static void Handle_DMA_Interrupts(void* context, alt_u32 id) {     //清除中断标志     IOWR_ALTERA_AVALON_DMA_STATUS(DMA_BASE, 0);     //停止DMA传输     IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_BASE, 0x092);     dma_end_flag = 1; }

/************************************/ static void DMA_Init(void)    //DMA初始化 {     //注册DMA中断     alt_irq_register(DMA_IRQ, NULL, Handle_DMA_Interrupts);     //设置传输模式为半字传输     IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_BASE, 0x092);     //清除中断标志     IOWR_ALTERA_AVALON_DMA_STATUS(DMA_BASE, 0);     //初始化源地址和目的地址     IOWR_ALTERA_AVALON_DMA_RADDRESS(DMA_BASE, SRC_ADDR);     IOWR_ALTERA_AVALON_DMA_WADDRESS(DMA_BASE, DST_ADDR);     //初始化长度寄存器     IOWR_ALTERA_AVALON_DMA_LENGTH(DMA_BASE, 2*DAT_LEN);     //启动DMA     IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_BASE, 0x09a); }