/********************************************************************************************************************
** 函数名称: U8_T SD_SendCmd() Name: U8_T SD_SendCmd()
** 功能描述: 向卡发送命令,并取得响应 Function: send command to the card,and get a response
** 输 入: U8_T cmd : 命令字 Input: U8_T cmd : command byte
U8_T *param : 命令参数,长度为4字节 U8_T *param : command parameter,length is 4 bytes
U8_T resptype : 响应类型 U8_T resptype: response type
U8_T *resp : 响应,长度为1-5字节 U8_T *resp : response,length is 1-5 bytes
** 输 出: 0: 正确 >0: 错误码 Output: 0: right >0: error code
********************************************************************************************************************/
U8_T SD_SendCmd(U8_T cmd, U8_T *param, U8_T resptype, U8_T *resp)
{
S8_T i;
U8_T tmp,rlen;
SPI_CS_Assert();
SPI_SendByte((cmd & 0x3F) | 0x40); /* 发送命令头和命令字 send command header and word */
for (i = 3; i >= 0; i--)
SPI_SendByte(param[i]); /* 发送参数 send parameters */
if(cmd == CMD8)
SPI_SendByte(CMD8_CRC);
else if(cmd == CMD0)
SPI_SendByte(0x95); /* CRC校验码,只用于第1个命令 CRC,only used for the first command */
else
SPI_SendByte(0x00);
rlen = 0;
switch (resptype) /* 根据不同的命令,得到不同的响应长度 */
{ /* according various command,get the various response length */
case R1:
case R1B: rlen = 1; break;
case R2: rlen = 2; break;
case R3:
case R7: rlen = 5; break;
default: SPI_SendByte(0xFF);
SPI_CS_Deassert();
return SD_ERR_CMD_RESPTYPE; /* 返回命令响应类型错误 return error of command response type */
break;
}
i = 0;
do /* 等待响应,响应的开始位为0 */
{ /* Wait for a response,a response is a start bit(zero) */
tmp = SPI_RecByte();
i++;
}while (((tmp & 0x80) != 0) && (i < SD_CMD_TIMEOUT));
if (i >= SD_CMD_TIMEOUT)
{
SPI_CS_Deassert();
return SD_ERR_CMD_TIMEOUT; /* 返回命令超时 return response timeout of command */
}
for (i = rlen - 1; i >= 0; i--)
{
resp[i] = tmp;
tmp = SPI_RecByte(); /* 循环的最后发送8clock at the last recycle,clock out 8 clock */
}
SPI_CS_Deassert();
return SD_NO_ERR; /* 返回执行成功 return perform sucessfully */
}
DRESULT disk_ioctl (
BYTE pdrv, /* Physical drive nmuber (0..) */
BYTE cmd, /* Control code */
void *buff /* Buffer to send/receive control data */
)
{
DRESULT res;
if (pdrv)
{
return RES_PARERR;
}
//FATFS目前版本仅需处理CTRL_SYNC，GET_SECTOR_COUNT，GET_BLOCK_SIZ三个命令
switch(cmd)
{
case CTRL_SYNC:
SPI_CS_Assert();
if(SD_ResetSD() == SD_NO_ERR)
{
res = RES_OK;
}
else
{
res = RES_ERROR;
}
SPI_CS_Deassert();
break;
case GET_BLOCK_SIZE:
*(WORD*)buff = 512;
res = RES_OK;
break;
case GET_SECTOR_COUNT:
*(DWORD*)buff = SD_GetCardInfo();
res = RES_OK;
break;
default:
res = RES_PARERR;
break;
}
return res;
}