spiflash.c

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/*! \file spiflash.c \brief SPI Flash Memory Driver (M25Pxx/AT25Fxxx/etc). */
//*****************************************************************************
//
// File Name    : 'spiflash.c'
// Title        : SPI Flash Memory Driver (M25Pxx/AT25Fxxx/etc)
// Author       : Pascal Stang - Copyright (C) 2006
// Created      : 2006-04-15
// Revised      : 2006-07-02
// Version      : 0.1
// Target MCU   : ARM processors
// Editor Tabs  : 4
//
// NOTE: This code is currently below version 1.0, and therefore is considered
// to be lacking in some functionality or documentation, or may not be fully
// tested.  Nonetheless, you can expect most functions to work.
//
//*****************************************************************************

// system includes
#include "at91sam7s64.h"
#include "global.h"

// local includes
#include "spi.h"
#include "spiflash.h"
/*
#define SPIFLASH_CONFIG_CS      AT91C_BASE_PIOA->PIO_PER = AT91C_PIO_PA11; \
                                AT91C_BASE_PIOA->PIO_OER = AT91C_PIO_PA11
#define SPIFLASH_ASSERT_CS      AT91C_BASE_PIOA->PIO_CODR = AT91C_PIO_PA11
#define SPIFLASH_RELEASE_CS     AT91C_BASE_PIOA->PIO_SODR = AT91C_PIO_PA11
*/

#define SPIFLASH_CONFIG_CS      AT91C_BASE_PIOA->PIO_PER = AT91C_PIO_PA30; \
                                AT91C_BASE_PIOA->PIO_OER = AT91C_PIO_PA30
#define SPIFLASH_ASSERT_CS      AT91C_BASE_PIOA->PIO_CODR = AT91C_PIO_PA30
#define SPIFLASH_RELEASE_CS     AT91C_BASE_PIOA->PIO_SODR = AT91C_PIO_PA30

// functions
void spiflashInit(void)
{
    // initialize spi
    //spiInit();
    // initialize chip select
    SPIFLASH_RELEASE_CS;
    SPIFLASH_CONFIG_CS;
}

unsigned short spiflashGetID(void)
{
    unsigned short id;

    SPIFLASH_ASSERT_CS;
    spiTransferByte(SPIFLASH_CMD_RDID);
    id  = spiTransferByte(0x00)<<8;
    id |= spiTransferByte(0x00);
    SPIFLASH_RELEASE_CS;

    return id;
}

void spiflashChipErase(void)
{
    // enable write
    SPIFLASH_ASSERT_CS;
    spiTransferByte(SPIFLASH_CMD_WREN);
    SPIFLASH_RELEASE_CS;

    // clock out dummy byte to waste time
    spiTransferByte(0x00);

    // do chip erase
    SPIFLASH_ASSERT_CS;
    spiTransferByte(SPIFLASH_CMD_CHIPERASE);
    SPIFLASH_RELEASE_CS;

    // clock out dummy byte to waste time
    spiTransferByte(0x00);

    // wait until write is done
    SPIFLASH_ASSERT_CS;
    spiTransferByte(SPIFLASH_CMD_RDSR);
    while(spiTransferByte(0x00) & SPIFLASH_STATUS_BUSY);
    SPIFLASH_RELEASE_CS;
}

void spiflashRead(unsigned long addr, unsigned long nbytes, unsigned char *data)
{
    // begin read
    SPIFLASH_ASSERT_CS;
    // issue read command
    spiTransferByte(SPIFLASH_CMD_READ);
    // send address
    spiTransferByte(addr>>16);
    spiTransferByte(addr>>8);
    spiTransferByte(addr>>0);
    // read data
    while(nbytes--)
        *data++ = spiTransferByte(0x00);
    // end read
    SPIFLASH_RELEASE_CS;
}

void spiflashWrite(unsigned long addr, unsigned long nbytes, unsigned char *data)
{
    unsigned int page;
    unsigned int i;
    unsigned int pagelen;

    // loop through pages to be programmed
    for(page=0; page<((nbytes+SPIFLASH_PAGESIZE-1)>>8); page++)
    {
        // program this page

        // enable write
        SPIFLASH_ASSERT_CS;
        spiTransferByte(SPIFLASH_CMD_WREN);
        SPIFLASH_RELEASE_CS;
        
        // clock out dummy byte to waste time
        spiTransferByte(0x00);

        // begin write
        SPIFLASH_ASSERT_CS;
        // issue write command
        spiTransferByte(SPIFLASH_CMD_PAGEPROG);
        // send address
        spiTransferByte(addr>>16);
        spiTransferByte(addr>>8);
        spiTransferByte(addr>>0);
        // program exactly the number of bytes requested
        if( ((page<<8)+SPIFLASH_PAGESIZE) <= nbytes)
            pagelen = SPIFLASH_PAGESIZE;
        else
            pagelen = nbytes-(page<<8);
        // transfer data
        for(i=0; i<pagelen; i++)
            spiTransferByte(*data++);
        // end write
        SPIFLASH_RELEASE_CS;

        // clock out dummy byte to waste time
        spiTransferByte(0x00);

        // wait until write is done
        SPIFLASH_ASSERT_CS;
        spiTransferByte(SPIFLASH_CMD_RDSR);
        while(spiTransferByte(0x00) & SPIFLASH_STATUS_BUSY);
        SPIFLASH_RELEASE_CS;

        // clock out dummy byte to waste time
        spiTransferByte(0x00);
    }
}

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