各位兄弟姐妹们，能不能帮我一个忙啊，小弟在用SPI读SD卡式，出现一个问题，前面的127个扇区可用正常读写，但是128及以后的扇区就不能读写了，不知道为什么啊！
ret=SD_Rd_Block(DBUF, 128);
返回值是255
源程序如下，请教高人指点啊！ 先谢谢了！
byte SD_Rd_Block(Uint16 *buff, unsigned long address)
{
Uint16 count;
//Block size is 512 bytes exactly
//First Lower SS
byte resp;
SD_Assert();
//Then send write command
SD_Wt_Cmd(0x11,address<<9,0xff);
resp=SD_Rd_Resp();
if(resp!=0)
return resp;
//command was a success - now send data
//start with DATA TOKEN = 0xFE
while(SD_Rd_Byte()!=0xfe);
for(count=0;count<128;count++)
{
*buff|=(Uint16)(SD_Rd_Byte()<<8);
*buff|= (Uint16)(SD_Rd_Byte());
*buff++;
*buff|=(Uint16)(SD_Rd_Byte()<<8);
*buff|=(Uint16)(SD_Rd_Byte());
*buff++;
}
//data block sent - now send checksum
SD_Rd_Byte();
SD_Rd_Byte();
//Now read in the DATA RESPONSE token
SD_deAssert();//SD_CS=1
SD_Rd_Byte();
return 1;
//printf("Command 0x11 (Read) was not received by the MMC.\n");
}
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楼主
