File content as of revision 0:d4197e4552ea:

#include "mbed.h"
#include "mbed_debug.h"

#define SD_COMMAND_TIMEOUT 5000

#define SD_DBG             0

#define R1_IDLE_STATE           (1 << 0)
#define R1_ERASE_RESET          (1 << 1)
#define R1_ILLEGAL_COMMAND      (1 << 2)
#define R1_COM_CRC_ERROR        (1 << 3)
#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
#define R1_ADDRESS_ERROR        (1 << 5)
#define R1_PARAMETER_ERROR      (1 << 6)

int initialise_card();
int initialise_card_v1();
int initialise_card_v2();
int cmd(int, int);
int cmd58();
int cmd8();

int cdv;

#define SDCARD_FAIL 0
#define SDCARD_V1   1
#define SDCARD_V2   2
#define SDCARD_V2HC 3



SPI spi(PTD6, PTD7, PTD5); // mosi, miso, sclk
DigitalOut cs(PTD2);



int main()
{
    while(1)
    { initialise_card();
      int result= initialise_card();
      printf("%d\n",result);
    }
}




int initialise_card() {
    // Set to 100kHz for initialisation, and clock card with cs = 1
    spi.frequency(100000);
    cs = 1;
    for (int i = 0; i < 16; i++) {
        spi.write(0xFF);
    }
    
    // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
    if (cmd(0, 0) != R1_IDLE_STATE) {
        debug("No disk, or could not put SD card in to SPI idle state\n");
        return SDCARD_FAIL;
    }

 // send CMD8 to determine whther it is ver 2.x
    int r = cmd8();
    if (r == R1_IDLE_STATE) {
        return initialise_card_v2();
    } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
        return initialise_card_v1();
    } else {
        debug("Not in idle state after sending CMD8 (not an SD card?)\n");
        return SDCARD_FAIL;
    }
}

int initialise_card_v1() {
    for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
        cmd(55, 0);
        if (cmd(41, 0) == 0) {
            cdv = 512;
            debug_if(SD_DBG, "\n\rInit: SEDCARD_V1\n\r");
            return SDCARD_V1;
        }
    }
    
    debug("Timeout waiting for v1.x card\n");
    return SDCARD_FAIL;
}


int initialise_card_v2() {
    for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
        wait_ms(50);
        cmd58();
        cmd(55, 0);
        if (cmd(41, 0x40000000) == 0) {
            cmd58();
            debug_if(SD_DBG, "\n\rInit: SDCARD_V2\n\r");
            cdv = 1;
            return SDCARD_V2;
        }
    }
    
    debug("Timeout waiting for v2.x card\n");
    return SDCARD_FAIL;
}

int cmd(int cmd, int arg) {
    cs = 0;
    
    // send a command
    spi.write(0x40 | cmd);
    spi.write(arg >> 24);
    spi.write(arg >> 16);
    spi.write(arg >> 8);
    spi.write(arg >> 0);
    spi.write(0x95);
    
    // wait for the repsonse (response[7] == 0)
for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
        int response = spi.write(0xFF);
        if (!(response & 0x80)) {
            cs = 1;
            spi.write(0xFF);
            return response;
        }
    }
    cs = 1;
    spi.write(0xFF);
    return -1; // timeout
}


int cmd58() {
    cs = 0;
    int arg = 0;
    
    // send a command
    spi.write(0x40 | 58);
    spi.write(arg >> 24);
    spi.write(arg >> 16);
    spi.write(arg >> 8);
    spi.write(arg >> 0);
    spi.write(0x95);
    
    // wait for the repsonse (response[7] == 0)
    for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
        int response = spi.write(0xFF);
        if (!(response & 0x80)) {
            int ocr = spi.write(0xFF) << 24;
            ocr |= spi.write(0xFF) << 16;
            ocr |= spi.write(0xFF) << 8;
            ocr |= spi.write(0xFF) << 0;
            cs = 1;
            spi.write(0xFF);
            return response;
        }
    }
    cs = 1;
    spi.write(0xFF);
    return -1; // timeout
}


int cmd8() {
    cs = 0;
    
    // send a command
    spi.write(0x40 | 8); // CMD8
    spi.write(0x00);     // reserved
    spi.write(0x00);     // reserved
    spi.write(0x01);     // 3.3v
    spi.write(0xAA);     // check pattern
    spi.write(0x87);     // crc
    
    // wait for the repsonse (response[7] == 0)
    for (int i = 0; i < SD_COMMAND_TIMEOUT * 1000; i++) {
        char response[5];
        response[0] = spi.write(0xFF);
        if (!(response[0] & 0x80)) {
            for (int j = 1; j < 5; j++) {
                response[i] = spi.write(0xFF);
            }
            cs = 1;
            spi.write(0xFF);
            return response[0];
        }
    }
    cs = 1;
    spi.write(0xFF);
    return -1; // timeout
}