aaspi_slave.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    : aaspi_slave.c
|--------------------------------------------------------------------------
| Configure the device as an SPI slave and watch incoming data.
|--------------------------------------------------------------------------
| 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 "aardvark.h"


//=========================================================================
// CONSTANTS
//=========================================================================
#define BUFFER_SIZE      65535

#define SLAVE_RESP_SIZE     26


//=========================================================================
// FUNCTIONS
//=========================================================================
static u08 data_in[BUFFER_SIZE];

static void dump (Aardvark handle, int timeout_ms)
{
    int trans_num = 0;
    int result;

    printf("Watching slave SPI data...\n");

    // Wait for data on bus
    result = aa_async_poll(handle, timeout_ms);
    if (result != AA_ASYNC_SPI) {
        printf("No data available.\n");
        return;
    }
    
    printf("\n");

    // Loop until aa_spi_slave_read times out
    for (;;) {
        int num_read;
        
        // Read the SPI message.
        // This function has an internal timeout (see datasheet).
        // To use a variable timeout the function aa_async_poll could
        // be used for subsequent messages.
        num_read = aa_spi_slave_read(handle, BUFFER_SIZE, data_in);

        if (num_read < 0 && num_read != AA_SPI_SLAVE_TIMEOUT) {
            printf("error: %s\n", aa_status_string(num_read));
            return;
        }
        else if (num_read == 0 || num_read == AA_SPI_SLAVE_TIMEOUT) {
            printf("No more data available from SPI master.\n");
            return;
        }
        else {
            int i;
            // Dump the data to the screen
            printf("*** Transaction #%02d\n", trans_num);
            printf("Data read from device:");
            for (i = 0; i < num_read; ++i) {
                if ((i&0x0f) == 0)      printf("\n%04x:  ", i);
                printf("%02x ", data_in[i] & 0xff);
                if (((i+1)&0x07) == 0)  printf(" ");
            }
            printf("\n\n");
            
            ++trans_num;
        }
    }
}


//=========================================================================
// MAIN PROGRAM
//=========================================================================
int main (int argc, char *argv[]) {
    Aardvark handle;

    int port       = 0;
    int mode       = 0;
    int timeout_ms = 0;
    
    u08 slave_resp[SLAVE_RESP_SIZE];
    int i;

    if (argc < 4) {
        printf("usage: aaspi_slave PORT MODE TIMEOUT_MS\n");
        printf("  mode 0 : pol = 0, phase = 0\n");
        printf("  mode 1 : pol = 0, phase = 1\n");
        printf("  mode 2 : pol = 1, phase = 0\n");
        printf("  mode 3 : pol = 1, phase = 1\n");
        printf("\n");
        printf("  The timeout value specifies the time to\n");
        printf("  block until the first packet is received.\n");
        printf("  If the timeout is -1, the program will\n");
        printf("  block indefinitely.\n");
        return 1;
    }

    port       = atoi(argv[1]);
    mode       = atoi(argv[2]);
    timeout_ms = atoi(argv[3]);

    // 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 SPI subsystem is enabled
    aa_configure(handle, AA_CONFIG_SPI_I2C);

    // Disable the Aardvark adapter's power pins.
    // 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_NONE);

    // Setup the clock phase
    aa_spi_configure(handle, mode >> 1, mode & 1, AA_SPI_BITORDER_MSB);

    // Set the slave response
    for (i=0; i<SLAVE_RESP_SIZE; ++i)
        slave_resp[i] = 'A' + i;

    aa_spi_slave_set_response(handle, SLAVE_RESP_SIZE, slave_resp);
    
    // Enable the slave
    aa_spi_slave_enable(handle);

    // Watch the SPI port
    dump(handle, timeout_ms);

    // Disable the slave and close the device
    aa_spi_slave_disable(handle);
    aa_close(handle);

    return 0;
}