aai2c_eeprom.c

Aardvark Example Source Code Version: 4.00 Date: 2007-04-20 Source code which shows how to use the

/*=========================================================================
| (c) 2003-2007  Total Phase, Inc.
|--------------------------------------------------------------------------
| Project : Aardvark Sample Code
| File    : aai2c_eeprom.c
|--------------------------------------------------------------------------
| Perform simple read and write operations to an I2C EEPROM device.
|--------------------------------------------------------------------------
| Redistribution and use of this file in source and binary forms, with
| or without modification, are permitted.
|
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
| "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
| LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
| FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
| COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
| INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
| BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
| LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
| CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
| LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
| ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
| POSSIBILITY OF SUCH DAMAGE.
 ========================================================================*/

//=========================================================================
// INCLUDES
//=========================================================================
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "aardvark.h"


//=========================================================================
// CONSTANTS
//=========================================================================
#define PAGE_SIZE 8


//=========================================================================
// FUNCTION
//=========================================================================
static void _writeMemory (Aardvark handle, u08 device, u08 addr, u16 length,
                          int zero)
{
    u16 i, n;
    u08 data_out[1+PAGE_SIZE];

    // Write to the I2C EEPROM
    //
    // The AT24C02 EEPROM has 8 byte pages.  Data can written
    // in pages, to reduce the number of overall I2C transactions
    // executed through the Aardvark adapter.
    n = 0;
    while (n < length) {
        // Fill the packet with data
        data_out[0] = addr;
        
        // Assemble a page of data
        i = 1;
        do {
            data_out[i++] = zero ? 0 : (u08)n;
            ++addr; ++n;
        } while ( n < length && (addr & (PAGE_SIZE-1)) );

        // Write the address and data
        aa_i2c_write(handle, device, AA_I2C_NO_FLAGS, i, data_out);
        aa_sleep_ms(10);
    }
}


static void _readMemory (Aardvark handle, u08 device, u08 addr, u16 length)
{
    int count, i;
    u08 *data_in = (u08 *)malloc(length);

    // Write the address
    aa_i2c_write(handle, device, AA_I2C_NO_STOP, 1, &addr);

    count = aa_i2c_read(handle, device, AA_I2C_NO_FLAGS, length, data_in);
    if (count < 0) {
        printf("error: %s\n", aa_status_string(count));
        return;
    }
    if (count == 0) {
        printf("error: no bytes read\n");
        printf("  are you sure you have the right slave address?\n");
        return;
    }
    else if (count != length) {
        printf("error: read %d bytes (expected %d)\n", count, length);
    }

    // Dump the data to the screen
    printf("\nData read from device:");
    for (i = 0; i < count; ++i) {
        if ((i&0x0f) == 0)      printf("\n%04x:  ", addr+i);
        printf("%02x ", data_in[i] & 0xff);
        if (((i+1)&0x07) == 0)  printf(" ");
    }
    printf("\n");

    // Free the data_in pointer
    free(data_in);
}


//=========================================================================
// MAIN PROGRAM
//=========================================================================
int main (int argc, char *argv[]) {
    Aardvark handle;
    int port    = 0;
    int bitrate = 100;
    u08 device;
    u08 addr;
    u16 length;
    
    const char *command;

    if (argc < 7) {
        printf("usage: aai2c_eeprom PORT BITRATE read  SLAVE_ADDR OFFSET LENGTH\n");
        printf("usage: aai2c_eeprom PORT BITRATE write SLAVE_ADDR OFFSET LENGTH\n");
        printf("usage: aai2c_eeprom PORT BITRATE zero  SLAVE_ADDR OFFSET LENGTH\n");
        return 1;
    }

    port    = atoi(argv[1]);
    bitrate = atoi(argv[2]);
    command = argv[3];
    device  = (u08)strtol(argv[4], 0, 0);
    addr    = (u08)strtol(argv[5], 0, 0);
    length  = atoi(argv[6]);

    // Open the device
    handle = aa_open(port);
    if (handle <= 0) {
        printf("Unable to open Aardvark device on port %d\n", port);
        printf("Error code = %d\n", handle);
        return 1;
    }

    // Ensure that the I2C subsystem is enabled
    aa_configure(handle,  AA_CONFIG_SPI_I2C);
    
    // Enable the I2C bus pullup resistors (2.2k resistors).
    // This command is only effective on v2.0 hardware or greater.
    // The pullup resistors on the v1.02 hardware are enabled by default.
    aa_i2c_pullup(handle, AA_I2C_PULLUP_BOTH);

    // Power the EEPROM using the Aardvark adapter's power supply.
    // This command is only effective on v2.0 hardware or greater.
    // The power pins on the v1.02 hardware are not enabled by default.
    aa_target_power(handle, AA_TARGET_POWER_BOTH);

    // Set the bitrate
    bitrate = aa_i2c_bitrate(handle, bitrate);
    printf("Bitrate set to %d kHz\n", bitrate);

    // Perform the operation
    if (strcmp(command, "write") == 0) {
        _writeMemory(handle, device, addr, length, 0);
        printf("Wrote to EEPROM\n");
    }
    else if (strcmp(command, "read") == 0) {
        _readMemory(handle, device, addr, length);
    }
    else if (strcmp(command, "zero") == 0) {
        _writeMemory(handle, device, addr, length, 1);
        printf("Zeroed EEPROM\n");
    }
    else {
        printf("unknown command: %s\n", command);
    }

    // Close the device and exit
    aa_close(handle);
    return 0;
}