library

/*! \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   : AVR 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 "avr/io.h"
#include "global.h"

// library includes
#include "spi.h"
#include "spiflash.h"

#define SPIFLASH_CONFIG_CS              DDRB  |= (1<<0)
#define SPIFLASH_ASSERT_CS              PORTB &= (1<<0)
#define SPIFLASH_RELEASE_CS             PORTB |= (1<<0)

// 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;
        spiByte(0, SPIFLASH_CMD_RDID, 0);
        id  = spiByte(0, 0x00, 0)<<8;
        id |= spiByte(0, 0x00, 1);
        SPIFLASH_RELEASE_CS;

        return id;
}

void spiflashChipErase(void)
{
        // enable write
        SPIFLASH_ASSERT_CS;
        spiByte(0, SPIFLASH_CMD_WREN, 1);
        SPIFLASH_RELEASE_CS;

        // clock out dummy byte to waste time
        spiByte(0, 0x00, 1);

        // do chip erase
        SPIFLASH_ASSERT_CS;
        spiByte(0, SPIFLASH_CMD_CHIPERASE, 1);
        SPIFLASH_RELEASE_CS;

        // clock out dummy byte to waste time
        spiByte(0, 0x00, 1);

        // wait until write is done
        SPIFLASH_ASSERT_CS;
        spiByte(0, SPIFLASH_CMD_RDSR, 0);
        while(spiByte(0, 0x00, 0) & 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
        spiByte(0, SPIFLASH_CMD_READ, 0);
        // send address
        spiByte(0, addr>>16, 0);
        spiByte(0, addr>>8, 0);
        spiByte(0, addr>>0, 0);
        // read data
        while(nbytes--)
                *data++ = spiByte(0, 0x00, 0);
        // 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;
                spiByte(0, SPIFLASH_CMD_WREN, 1);
                SPIFLASH_RELEASE_CS;
                
                // clock out dummy byte to waste time
                spiByte(0, 0x00, 1);

                // begin write
                SPIFLASH_ASSERT_CS;
                // issue write command
                spiByte(0, SPIFLASH_CMD_PAGEPROG, 0);
                // send address
                spiByte(0, addr>>16, 0);
                spiByte(0, addr>>8, 0);
                spiByte(0, addr>>0, 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++)
                        spiByte(0, *data++, 0);
                // end write
                SPIFLASH_RELEASE_CS;

                // clock out dummy byte to waste time
                spiByte(0, 0x00, 1);

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

                // clock out dummy byte to waste time
                spiByte(0, 0x00, 1);
        }
}