hal.c

读SD卡用SST单片机与tlc5620播放音乐程序

#include "HAL.H"

//============================================================
//往SD卡定一字节 
void SdWrite(unsigned char  n)
{ 
  unsigned char i;
  for(i=8;i;i--)
   {
    SD_CLK=0;
    SD_DI=(n&0x80);
    n<<=1;
    SD_CLK=1;
   }
  SD_DI=1;      
}   
//================================================================
//从SD卡读一字节
unsigned char SdRead()
{
 unsigned char n,i;
 for(i=8;i;i--)
  {
   SD_CLK=0;
   SD_CLK=1;
   n<<=1;
   if(SD_DO) n|=1;

  }
 return n;
}
//================================================================
//读SD卡响应 
unsigned char SdResponse()
{
  unsigned char i=0,response;
  while(i<=8)
  {
    response=SdRead();
    if(response==0x00)
      break;
    if(response==0x01)
      break;
    i++;
  }
  return response;
}  
//================================================================
void SdCommand(unsigned char command, unsigned long argument, unsigned char CRC)
{
  SdWrite(command|0x40);
  SdWrite(((unsigned char *)&argument)[0]);
  SdWrite(((unsigned char *)&argument)[1]);
  SdWrite(((unsigned char *)&argument)[2]);
  SdWrite(((unsigned char *)&argument)[3]);
  SdWrite(CRC);
}
//================================================================
unsigned char SdInit(void)
{
  int delay=0, trials=0;
  unsigned char i;
  unsigned char response=0x01;
  SD_CS=1;
  for(i=0;i<=9;i++)
    SdWrite(0xff);
  SD_CS=0;
  
  //Send Command 0 to put MMC in SPI mode
  SdCommand(0x00,0,0x95);

  
  response=SdResponse();
  
  if(response!=0x01)
   {
    return 0;
   } 
  
  while(response==0x01)
  {
    SD_CS=1;
    SdWrite(0xff);
    SD_CS=0;
    SdCommand(0x01,0x00ffc000,0xff);
    response=SdResponse();
  } 
    
  SD_CS=1;
  SdWrite(0xff);
  return 1;  
}
//================================================================
unsigned char SdWriteBlock(unsigned char *Block, unsigned long address)
{
  unsigned char count;
  unsigned char dataResp;
  //Block size is 512 bytes exactly
  //First Lower SS
  
  SD_CS=0;
  //Then send write command
  SdCommand(0x18,address,0xff);
  
  if(SdResponse()==00)
  {
    SdWrite(0xff);
	SdWrite(0xff);
	SdWrite(0xff);
    //command was a success - now send data
    //start with DATA TOKEN = 0xFE
    SdWrite(0xfe);
    //now send data
    for(count=0;count<128;count++)
    {
      SdWrite(*Block++);
	  SdWrite(*Block++);
	  SdWrite(*Block++);
	  SdWrite(*Block++);
    }
    //data block sent - now send checksum
    SdWrite(0xff);
    SdWrite(0xff);
    //Now read in the DATA RESPONSE token
    dataResp=SdRead();
    //Following the DATA RESPONSE token
    //are a number of BUSY bytes
    //a zero byte indicates the MMC is busy

    while(SdRead()==0);

    dataResp=dataResp&0x0f;	//mask the high byte of the DATA RESPONSE token
    SD_CS=1;
    SdWrite(0xff);
    if(dataResp==0x0b)
      {
      //DATA WAS NOT ACCEPTED BY CARD -- CRC ERROR
      return 0;
      }
    if(dataResp==0x05)
      return 1;
      
    //Invalid data Response token.
    return 0;
 }
  //Command 0x18 (Write) was not received by the MMC
  return 0;
}
//=======================================================================
unsigned char SdReadBlock(unsigned char *Block, unsigned long address)
{
   unsigned char count;
  //Block size is 512 bytes exactly
  //First Lower SS
  
// MMC_read_block
  
  SD_CS=0;
  
   //SdWrite(0xff);
  //Then send write command
  SdCommand(0x11,address,0xff);

  if(SdResponse()==00)
  {
    //command was a success - now send data
    //start with DATA TOKEN = 0xFE
    while(SdRead()!=0xfe);

    for(count=0;count<128;count++)
    {
      *Block++=SdRead();
	  *Block++=SdRead();
	  *Block++=SdRead();
	  *Block++=SdRead();
    }
    //data block sent - now send checksum
    SdRead();
    SdRead();
    //Now read in the DATA RESPONSE token
    SD_CS=1;
    SdRead();
    return 1;
 }
		//Command 0x11 (Read) was not received by the MMC
  return 0;
}


unsigned char SdReadSector(unsigned long sector,unsigned char len,unsigned char *pBuffer)
{
	while(len--)
	 {
	  if(SdReadBlock(pBuffer,sector<<9)==0) 
             return 0;
      pBuffer+=512;
	 }
  return 1;
}

unsigned char SdWriteSector(unsigned long sector,unsigned char len,unsigned char *pBuffer)
{
	while(len--)
	 {
	  if(SdWriteBlock(pBuffer,sector<<9)==0) return 0;
      pBuffer+=512;
	 }
 return 1;  
}