super6502/sw/bios/devices/sd_card.c

#include <conio.h>

#include "sd_card.h"
#include "sd_print.h"
#include "spi.h"

/*******************************************************************************
 Initialize SD card
*******************************************************************************/
uint8_t SD_init()
{
    uint16_t i;

    uint8_t res[5], cmdAttempts = 0;

    SD_powerUpSeq();

    while((res[0] = SD_goIdleState()) != SD_IN_IDLE_STATE)
    {
        cmdAttempts++;
        if(cmdAttempts == CMD0_MAX_ATTEMPTS)
        {
            cputs("Go IDLE\r\n");
            return SD_ERROR;
        }
    }

    for (i = 0; i < 1000; i++);

    SD_sendIfCond(res);
    if(res[0] != SD_IN_IDLE_STATE)
    {
        cputs("IF Cond\r\n");
        return SD_ERROR;
    }

    if(res[4] != 0xAA)
    {
        return SD_ERROR;
    }

    cmdAttempts = 0;
    do
    {
        if(cmdAttempts == CMD55_MAX_ATTEMPTS)
        {
            cputs("op_cond error\r\n");
            return SD_ERROR;
        }

        res[0] = SD_sendApp();
        if(SD_R1_NO_ERROR(res[0]))
        {
            res[0] = SD_sendOpCond();
        }

        for (i = 0; i < 1000; i++);

        cmdAttempts++;
    }
    while(res[0] != SD_READY);

    for (i = 0; i < 1000; i++);

    SD_readOCR(res);

    return SD_SUCCESS;
}

/*
// Send a command with starting end ending clock pulses
uint8_t res1_cmd(uint8_t cmd, uint32_t arg, uint8_t crc)
{
    uint8_t res1;
    // assert chip select
    spi_exchange(0xFF);
    spi_select(0);
    spi_exchange(0xFF);

    // send CMD0
    SD_command(cmd, arg, crc);

    // read response
    res1 = SD_readRes1();

    // deassert chip select
    spi_exchange(0xFF);
    spi_deselect(0);
    spi_exchange(0xFF);

    return res1;
}
*/

/*******************************************************************************
 Run power up sequence
*******************************************************************************/
/*
void SD_powerUpSeq()
{
    uint16_t i;
    uint8_t j;

    // make sure card is deselected
    spi_deselect(0);

    // give SD card time to power up
    for (i = 0; i < 1000; i++);


    // select SD card
    spi_exchange(0xFF);
    spi_deselect(0);

    // send 80 clock cycles to synchronize
    for(j = 0; j < SD_INIT_CYCLES; j++)
        spi_exchange(0xFF);
}
*/

/*******************************************************************************
 Send command to SD card
*******************************************************************************/
/*
void SD_command(uint8_t cmd, uint32_t arg, uint8_t crc)
{
    // transmit command to sd card
    spi_exchange(cmd|0x40);

    // transmit argument
    spi_exchange((uint8_t)(arg >> 24));
    spi_exchange((uint8_t)(arg >> 16));
    spi_exchange((uint8_t)(arg >> 8));
    spi_exchange((uint8_t)(arg));

    // transmit crc
    spi_exchange(crc|0x01);
}
*/

/*******************************************************************************
 Read R1 from SD card
*******************************************************************************/
/*
uint8_t SD_readRes1()
{
    uint8_t i = 0, res1;

    // keep polling until actual data received
    while((res1 = spi_exchange(0xFF)) == 0xFF)
    {
        i++;

        // if no data received for 8 bytes, break
        if(i > 8) break;
    }

    return res1;
}
*/

/*******************************************************************************
 Read R2 from SD card
*******************************************************************************/
/*
void SD_readRes2(uint8_t *res)
{
    // read response 1 in R2
    res[0] = SD_readRes1();

    // read final byte of response
    res[1] = spi_exchange(0xFF);
}
*/

/*******************************************************************************
 Read R3 from SD card
*******************************************************************************/
/*
void SD_readRes3(uint8_t *res)
{
    // read response 1 in R3
    res[0] = SD_readRes1();

    // if error reading R1, return
    if(res[0] > 1) return;

    // read remaining bytes
    SD_readBytes(res + 1, R3_BYTES);
}
*/

/*******************************************************************************
 Read R7 from SD card
*******************************************************************************/
/*
void SD_readRes7(uint8_t *res)
{
    // read response 1 in R7
    res[0] = SD_readRes1();

    // if error reading R1, return
    if(res[0] > 1) return;

    // read remaining bytes
    SD_readBytes(res + 1, R7_BYTES);
}
*/

/*******************************************************************************
 Read specified number of bytes from SD card
*******************************************************************************/
/*
void SD_readBytes(uint8_t *res, uint8_t n)
{
    while(n--) *res++ = spi_exchange(0xFF);
}
*/

/*******************************************************************************
 Command Idle State (CMD0)
*******************************************************************************/
uint8_t SD_goIdleState()
{
    return res1_cmd(CMD0, CMD0_ARG, CMD0_CRC);
}

/*******************************************************************************
 Send Interface Conditions (CMD8)
*******************************************************************************/
void SD_sendIfCond(uint8_t *res)
{
    // assert chip select
    spi_exchange(0xFF);
    spi_select(0);
    spi_exchange(0xFF);

    // send CMD8
    SD_command(CMD8, CMD8_ARG, CMD8_CRC);

    // read response
    SD_readRes7(res);
    //SD_readBytes(res + 1, R7_BYTES);

    // deassert chip select
    spi_exchange(0xFF);
    spi_deselect(0);
    spi_exchange(0xFF);
}

/*******************************************************************************
 Read Status
*******************************************************************************/
void SD_sendStatus(uint8_t *res)
{
    // assert chip select
    spi_exchange(0xFF);
    spi_select(0);
    spi_exchange(0xFF);

    // send CMD13
    SD_command(CMD13, CMD13_ARG, CMD13_CRC);

    // read response
    SD_readRes2(res);

    // deassert chip select
    spi_exchange(0xFF);
    spi_deselect(0);
    spi_exchange(0xFF);
}

/*******************************************************************************
 Read single 512 byte block
 token = 0xFE - Successful read
 token = 0x0X - Data error
 token = 0xFF - timeout
*******************************************************************************/
// uint8_t SD_readSingleBlock(uint32_t addr, uint8_t *buf, uint8_t *token)
// {
//     uint8_t res1, read;
//     uint16_t readAttempts;
//     uint16_t i;

//     // set token to none
//     *token = 0xFF;

//     // assert chip select
//     spi_exchange(0xFF);
//     spi_select(0);
//     spi_exchange(0xFF);

//     // send CMD17
//     SD_command(CMD17, addr, CMD17_CRC);

//     // read R1
//     res1 = SD_readRes1();

//     // if response received from card
//     if(res1 != 0xFF)
//     {
//         // wait for a response token (timeout = 100ms)
//         readAttempts = 0;
//         while(++readAttempts != SD_MAX_READ_ATTEMPTS)
//             if((read = spi_exchange(0xFF)) != 0xFF) break;

//         cprintf("read attempts: %d\r\n", readAttempts);

//         // if response token is 0xFE
//         if(read == SD_START_TOKEN)
//         {
//             // read 512 byte block
//             for(i = 0; i < SD_BLOCK_LEN; i++) *buf++ = spi_exchange(0xFF);

//             // read 16-bit CRC
//             spi_exchange(0xFF);
//             spi_exchange(0xFF);
//         }

//         // set token to card response
//         *token = read;
//     }

//     // deassert chip select
//     spi_exchange(0xFF);
//     spi_deselect(0);
//     spi_exchange(0xFF);

//     return res1;
// }

#define SD_MAX_WRITE_ATTEMPTS   3907

/*******************************************************************************
Write single 512 byte block
token = 0x00 - busy timeout
token = 0x05 - data accepted
token = 0xFF - response timeout
*******************************************************************************/
uint8_t SD_writeSingleBlock(uint32_t addr, uint8_t *buf, uint8_t *token)
{
    uint16_t readAttempts;
    uint8_t res1, read;
    uint16_t i;

    /*

    // set token to none
    *token = 0xFF;

    // assert chip select
    spi_exchange(0xFF);
    spi_select(0);
    spi_exchange(0xFF);

    // send CMD24
    SD_command(CMD24, addr, CMD24_CRC);

    // read response
    res1 = SD_readRes1();

    // if no error
    if(res1 == SD_READY)
    {
        // send start token
        spi_exchange(SD_START_TOKEN);

        // write buffer to card
        for(i = 0; i < SD_BLOCK_LEN; i++) spi_exchange(buf[i]);

        // wait for a response (timeout = 250ms)
        readAttempts = 0;
        while(++readAttempts != SD_MAX_WRITE_ATTEMPTS)
            if((read = spi_exchange(0xFF)) != 0xFF) { *token = 0xFF; break; }

        // if data accepted
        if((read & 0x1F) == 0x05)
        {
            // set token to data accepted
            *token = 0x05;

            // wait for write to finish (timeout = 250ms)
            readAttempts = 0;
            while(spi_exchange(0xFF) == 0x00)
                if(++readAttempts == SD_MAX_WRITE_ATTEMPTS) { *token = 0x00; break; }
        }
    }

    // deassert chip select
    spi_exchange(0xFF);
    spi_deselect(0);
    spi_exchange(0xFF);

    */

    return res1;
}

/*******************************************************************************
 Reads OCR from SD Card
*******************************************************************************/
void SD_readOCR(uint8_t *res)
{
    uint8_t tmp;

    // assert chip select
    spi_exchange(0xFF);
    spi_select(0);
    tmp = spi_exchange(0xFF);

    if(tmp != 0xFF) while(spi_exchange(0xFF) != 0xFF) ;

    // send CMD58
    SD_command(CMD58, CMD58_ARG, CMD58_CRC);

    // read response
    SD_readRes3(res);

    // deassert chip select
    spi_exchange(0xFF);
    spi_deselect(0);
    spi_exchange(0xFF);
}

/*******************************************************************************
 Send application command (CMD55)
*******************************************************************************/
uint8_t SD_sendApp()
{
    return res1_cmd(CMD55, CMD55_ARG, CMD55_CRC);;
}

/*******************************************************************************
 Send operating condition (ACMD41)
*******************************************************************************/
uint8_t SD_sendOpCond()
{
    return res1_cmd(ACMD41, ACMD41_ARG, ACMD41_CRC);
}