main.c

Interfacing to an MMC/SD card via SPI (for microcontroller)

//*****************************************************************************
// Based on software by Pascal Stang, distributed under the GNU public license
// March 06    TWard       Ported to ecog1k, added support for SD cards
//*****************************************************************************


#include <ecog.h>
#include <ecog1.h>
#include "stdio.h"
#include "mmc.h"        // include MMC card access functions
#include "mmcConf.h"


void mmcTest(void);
void debugPrintHexTable(unsigned int length, unsigned char *buffer);

// Global card initialiser variable
int mmcCardInFlag;


//----- Begin Code ------------------------------------------------------------
int main(int argc, char* argv[])
{
    mmcTest();

    return (0);
}


void mmcTest(void)
{
    unsigned long sector = 0;
    unsigned char buffer[0x200];
    int c;
    unsigned int d;

    // initialize MMC interface
    mmcInit();
   
    // print new prompt
    printf("\r\ncmd>");

    // testing loop
    while(1)
    {
        if (mmcCardInFlag == 1)
        {
            // A card has been inserted, reset
            mmcCardInFlag = 0;
            printf("\r\nDetecting & resetting SD/MMC Card...");
            // We should provide a delay of half a second or so here
            for (c = 0; c < 32000; c++)
            {
                for (d = 0; d < 50; d++)
                    nop();
            }
            if (!mmcReset())
            {
                printf("Found SD Memory Card\n\r");
            }  
            else
            {
                LED0_Clr = 1;
                LED1_Clr = 1;
                printf("\n\rProblem Initialising Card!!\r\n");
            }
            // print new prompt
            printf("\r\ncmd>");
        }
        else
        {
            // check for keypress
            if (fd.duart.a_sts.rx_1b_rdy)
            {
                c = fd.duart.a_rx.data_1byte;
                switch(c)
                {
                    case 'i':
                    // initialize card 
                    mmcCardInFlag = 1;
                    break;
                    
                    case 'r':
                    // read current sector into buffer
                    printf("\r\nRead Sector %ld\r\n", sector);
                    mmcRead(sector, buffer);
                    // print buffer contents
                    debugPrintHexTable(0x200, buffer);
                    break;
                    
                    case 'w':
                    // write current sector with data from buffer
                    printf("\r\nWrite Sector %ld\r\n", sector);
                    mmcWrite(sector, buffer);
                    break;
                    
                    // move to new sector
                    case '+': sector++;        printf("\r\nSector = %ld", sector); break;
                    case '-': sector--;        printf("\r\nSector = %ld", sector); break;
                    case '*': sector+=512;    printf("\r\nSector = %ld", sector); break;
                    case '/': sector-=512;    printf("\r\nSector = %ld", sector); break;
                    case '\r':
                    default:
                    break;
                }            
                // print new prompt
                printf("\r\ncmd>");
            }
        }
    }
}


// Routine to print a hex table to the output
void debugPrintHexTable(unsigned int length, unsigned char *buffer)
{
    unsigned int i, j;
   
    for (i = 0; i < 0x20; i++)
    {
        printf("\r\n0x%2X0... ",i);
        for (j = 0; j < 0x10; j++)
        {
            printf ("%02X ",*buffer++);
        }
    }  
}


// Card IO handler
// The switch on the SD card needs to be de-bounced
void __irq_entry GPIO_Handler (void)
{
    // Check card status and update LED's
    if (MMC_LOCK_STATUS)
        LED1_Clr = 1; // Card is not locked
    else
        LED1_Set = 1; // Card is locked, turn off

    if (MMC_IN_STATUS)
    {  // Card is not in socket
        LED0_Clr = 1; // Card is not in socket
    }
    else
    {
        LED0_Set = 1; // Card is in socket
        mmcCardInFlag = 1;
    }
}