/****************************************************************************
* 名称 ： MMC_Write_sector
* 功能 ： 写MMC卡扇区,将BUF的数据写入扇区号sector
* 入口参数 ：sector，buf
* 出口参数 ：0
****************************************************************************/
unsigned char MMC_Write_sector(unsigned int sector, unsigned char *buf)
{
unsigned char *p, by;
unsigned int i,flag;
unsigned int startadr;
p = buf;
startadr = sector*(unsigned int)BYTE_PER_SEC;
Write_Command_MMC (MMC_WRITE_BLOCK,startadr);
SPI_TransferByte(0xFF);
SPI_TransferByte(0xFF);
SPI_TransferByte(0xFE);
for(i=0; i<BYTE_PER_SEC; i++)
{
SPI_TransferByte(*p++);
}
SPI_TransferByte(0xFF);
SPI_TransferByte(0xFF);
do
{
flag = SPI_TransferByte(0xFF);
by=flag & 0x1F;
}while(by != 0x05);
do
{
flag = SPI_TransferByte(0xFF);
}while(flag !=0xFF);
return 0;
}
Write_Command_MMC (MMC_WRITE_BLOCK,startadr);这句话怎么理解，写入了什么数据SPI_TransferByte(0xFF);
SPI_TransferByte(0xFF);
SPI_TransferByte(0xFE); 这3个又是什么，代表什么含义
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2014/3/24 8:26:58
