static uint8 send_slow_cmd (
uint8 cmd, /* Command byte */
uint32 arg /* Argument */
)
{
uint8 n, res;
uint8 cb[6];
int i;
(void)spi_slow_sr_byte(0xff);
i = 0;
do {
res = spi_slow_sr_byte(0xff);
i++;
} while ((res != 0xFF) && i < 100000);
if (res != 0xff) {
#ifdef SD_DEBUG
dbglog(DBG_DEBUG, "%s: CMD 0x%02x error\n", __func__, cmd);
#endif
return(0xff);
}
cb[0] = cmd;
cb[1] = (uint8)(arg >> 24);
cb[2] = (uint8)(arg >> 16);
cb[3] = (uint8)(arg >> 8);
cb[4] = (uint8)arg;
cb[5] = sd_crc7(cb, 5, 0);
/* Send command packet */
spi_slow_sr_byte(cmd); /* Command */
spi_slow_sr_byte(cb[1]); /* Argument[31..24] */
spi_slow_sr_byte(cb[2]); /* Argument[23..16] */
spi_slow_sr_byte(cb[3]); /* Argument[15..8] */
spi_slow_sr_byte(cb[4]); /* Argument[7..0] */
spi_slow_sr_byte(cb[5]); // CRC7
/* Receive command response */
if (cmd == CMD12)
(void)spi_slow_sr_byte(0xff);/* Skip a stuff byte when stop reading */
n = 20; /* Wait for a valid response in timeout of 10 attempts */
do {
res = spi_slow_sr_byte(0xff);
} while ((res & 0x80) && --n);
#ifdef SD_DEBUG
dbglog(DBG_DEBUG, "%s: CMD 0x%02x response 0x%02x\n", __func__, cmd, res);
#endif
return res; /* Return with the response value */
}
/**
* \ingroup sd_raw
* Send a command to the memory card which responses with a R1 response (and possibly others).
*
* \param[in] command The command to send.
* \param[in] arg The argument for command.
* \returns The command answer.
*/
uint8_t sd_raw_send_command(uint8_t command, uint32_t arg)
{
uint8_t response;
uint8_t *args = reinterpret_cast<uint8_t *>(&arg);
/* wait some clock cycles */
sd_raw_rec_byte();
#if !SD_RAW_SAVE_RAM
if ( sd_use_crc ) {
uint8_t crc[6] = { command | 0x40, args[3], args[2], args[1], args[0] };
crc[5] = sd_crc7(crc, 5);
for (uint8_t i = 0; i < 6; i++)
sd_raw_send_byte(crc[i]);
}
else {
#endif
/* send command via SPI */
sd_raw_send_byte(0x40 | command);
for (int8_t i = 3; i >= 0; i--)
sd_raw_send_byte(args[i]);
switch(command)
{
case CMD_GO_IDLE_STATE:
sd_raw_send_byte(0x95);
break;
case CMD_SEND_IF_COND:
sd_raw_send_byte(0x87);
break;
default:
sd_raw_send_byte(0xff);
break;
}
#if !SD_RAW_SAVE_RAM
}
#endif
/* receive response */
for(uint8_t i = 0; i < 10; ++i)
{
response = sd_raw_rec_byte();
if(response != 0xff)
break;
}
return response;
}
