Posted on July 02, 2012 at 20:39
You need pull up resistors on the pins, review a schematic for the STM3240G, or other, eval boards.
A more considered diskio solution would be along the following lines.
..
/*-----------------------------------------------------------------------*/
/* Return Disk Status */
DSTATUS disk_status (
BYTE drv /* Physical drive nmuber (0..) */
)
{
DSTATUS stat = 0;
if (SD_Detect() != SD_PRESENT)
stat |= STA_NODISK;
// STA_NOTINIT - Subsystem not initailized
// STA_PROTECTED - Write protected, MMC/SD switch if available
return(stat);
}
/*-----------------------------------------------------------------------*/
/* Read Sector(s) */
DRESULT disk_read (
BYTE drv, /* Physical drive nmuber (0..) */
BYTE *buff, /* Data buffer to store read data */
DWORD sector, /* Sector address (LBA) */
BYTE count /* Number of sectors to read (1..255) */
)
{
SD_Error Status;
printf(''disk_read %d %p %10d %d
'',drv,buff,sector,count);
if (SD_Detect() != SD_PRESENT)
return(RES_NOTRDY);
if ((DWORD)buff & 3) // DMA Alignment failure, do single up to aligned buffer
{
DRESULT res = RES_OK;
DWORD scratch[BLOCK_SIZE / 4]; // Alignment assured, you'll need a sufficiently big stack
while(count--)
{
res = disk_read(drv, (void *)scratch, sector++, 1);
if (res != RES_OK)
break;
memcpy(buff, scratch, BLOCK_SIZE);
buff += BLOCK_SIZE;
}
return(res);
}
Status = SD_ReadMultiBlocksFIXED(buff, sector, BLOCK_SIZE, count); // 4GB Compliant
if (Status == SD_OK)
{
SDTransferState State;
Status = SD_WaitReadOperation(); // Check if the Transfer is finished
while((State = SD_GetStatus()) == SD_TRANSFER_BUSY); // BUSY, OK (DONE), ERROR (FAIL)
if (State == SD_TRANSFER_ERROR)
return(RES_ERROR);
else
return(RES_OK);
}
else
return(RES_ERROR);
}
..
