read_write.c

这个程序是在DSP下 MMC SD卡读写程序

/*
 * Copyright (C) 2007 21CONTROL Incorporated
 * All Rights Reserved
 *
 *
 *---------read_write.c---------
 * This example does a write to the MMC/SD card and reads the
 * data written to verify the transfer.
 * This example is written for c5509. To run on c5509a, link in the
 * c5509a CSL library and define CHIP_5509A in the build options
 */

#include <csl_mmc.h>
#include <stdio.h>
#include <stdlib.h>

#pragma DATA_SECTION(mmc0,"cslmem")
MMC_Handle mmc0;
MMC_CardObj *card, cardalloc;
MMC_CardIdObj *cid, cardid;

int count, retVal;
Uint16 rca;
Uint16 cardtype;

/* Because of different operating clock frequencies, the Init structure for c5509    *
 * and c5509a have different values for memory and function clock divide down values */
#if CHIP_5509A
  MMC_SetupNative Init = {
    0,   /* Disable DMA for data read/write                 */
    0,   /* Set level of edge detection for DAT3 pin        */
    0,   /* Determines if MMC goes IDLE during IDLE instr   */
    1,   /* Memory clk reflected on CLK Pin                 */
    7,   /* CPU CLK to MMC function clk divide down         */
    5,   /* MMC function clk to memory clk divide down      */
    0,   /* No. memory clks to wait before response timeout */
    0,   /* No. memory clks to wait before data timeout     */
    512, /* Block Length must be same as CSD                */
  };
#else
  MMC_SetupNative Init = {
    0,   /* Disable DMA for data read/write                 */
    0,   /* Set level of edge detection for DAT3 pin        */
    0,   /* Determines if MMC goes IDLE during IDLE instr   */
    1,   /* Memory clk reflected on CLK Pin                 */
    3,   /* CPU CLK to MMC function clk divide down         */
    3,   /* MMC function clk to memory clk divide down      */
    0,   /* No. memory clks to wait before response timeout */
    0,   /* No. memory clks to wait before data timeout     */
    512, /* Block Length must be same as CSD                */
  };
#endif

/* Read and write buffers */
Uint16 datasend[512];
Uint16 datareceive[512];
  
void main()
{
  CSL_init();  
  for (count=0;count<=256;count++)
     {
           datasend[count]    = count+0xaa;
           datareceive[count] = 0xFFFF;
         }
  /* A detailed explanation of MMC initialization is provided in mmc_setup example */
   mmc0 = MMC_open(MMC_DEV1);
      for (count=0;count<30160;count++)
  	   asm("	NOP");  
   MMC_setupNative(mmc0,&Init);
     for (count=0;count<30160;count++)
  	   asm("	NOP");
   MMC_sendGoIdle(mmc0);
     for (count=0;count<30160;count++)
  	   asm("	NOP");
  
   cardtype = MMC_sendOpCond(mmc0,0x00100000);
     for (count=0;count<30160;count++)
  	   asm("	NOP"); 
   if (cardtype == MMC_CARD)
      {
        cid = &cardid;
        MMC_sendAllCID(mmc0,cid); // get the CID structure for all cards. 
        rca = 10;
        card = &cardalloc;
        retVal = MMC_setRca(mmc0,card,rca);
        } 
     else 
      {
        cid = &cardid;
        SD_sendAllCID(mmc0,cid); // get the CID structure for all cards.     
        card = &cardalloc;
        rca = SD_sendRca(mmc0,card);
       }
  
  /* Select the card to transfer data to/from. This step puts the card into the *
   * transfer state where it is ready to read/write data                        */
  
    retVal = MMC_selectCard(mmc0,card);

  /* MMC_write(Handle, start address, buffer pointer, length in bytes);         *
   * This does a single block transfer to the MMC card. Max length in bytes is  *
   * 512 bytes. datasend buffer has 256 elements of 16 bits each, which total   *
   * upto 512 bytes. By default data bus width is 1 bit. An SD card can support *
   * data bus width of 4 bits. The sd_set_width example shows how this is done  */
  
	  retVal = MMC_write(mmc0,0x00000000,datasend,512);
	  for (count = 0; count <= 25000; ++count)
	      asm("		NOP");
	  
	  for (count = 0; count <= 25000; ++count)
	      asm("		NOP");
	  
	  for (count = 0; count <= 25000; ++count)
	      asm("		NOP");
	
	  for (count = 0; count <= 25000; ++count)
	      asm("		NOP");
	            
	  /* MMC_read(Handle, start address, buffer pointer, length in bytes);          *
	   * This does a single block read from the MMC card. Max length in bytes for a *
	   * block is 512 bytes. datareceive buffer has 256 elements of 16 bits each,   *
	   * which total upto 512 bytes. By default data bus width is 1 bit. An SD card *
	   * can support a data bus width of 4 bits. The sd_set_width eg. explains this */ 
	  retVal = MMC_read(mmc0,0x00000000,datareceive,512); 
	  while(1);
}