aagpio.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    : aagpio.c
|--------------------------------------------------------------------------
| Perform some simple GPIO operations with a single Aardvark adapter.
|--------------------------------------------------------------------------
| 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"


//=========================================================================
// MAIN PROGRAM
//=========================================================================
int main (int argc, char *argv[]) {
    int port;
    u08 val;
    Aardvark handle;
    AardvarkExt aaext;

    if (argc < 2) {
        printf("usage: aagpio PORT\n");
        return 1;
    }

    port    = atoi(argv[1]);

    // Open the device
    handle  = aa_open_ext(port, &aaext);

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

    printf("Opened Aardvark adapter; features = 0x%02x\n", aaext.features);

    // Configure the Aardvark adapter so all pins
    // are now controlled by the GPIO subsystem
    aa_configure(handle, AA_CONFIG_GPIO_ONLY);

    // Turn off the external I2C line pullups
    aa_i2c_pullup(handle, AA_I2C_PULLUP_NONE);
    
    // Make sure the charge has dissipated on those lines
    aa_gpio_set(handle, 0x00);
    aa_gpio_direction(handle, 0xff);

    // By default all GPIO pins are inputs.  Writing 1 to the
    // bit position corresponding to the appropriate line will
    // configure that line as an output
    aa_gpio_direction(handle, AA_GPIO_SS | AA_GPIO_SCL);
    
    // By default all GPIO outputs are logic low.  Writing a 1
    // to the appropriate bit position will force that line
    // high provided it is configured as an output.  If it is
    // not configured as an output the line state will be
    // cached such that if the direction later changed, the
    // latest output value for the line will be enforced.
    aa_gpio_set(handle, AA_GPIO_SCL);
    printf("Setting SCL to logic low\n");
    
    // The get method will return the line states of all inputs.
    // If a line is not configured as an input the value of
    // that particular bit position in the mask will be 0.
    val = aa_gpio_get(handle);
    
    // Check the state of SCK
    if (val & AA_GPIO_SCK)
        printf("Read the SCK line as logic high\n");
    else
        printf("Read the SCK line as logic low\n");
    
    // Optionally we can set passive pullups on certain lines.
    // This can prevent input lines from floating.  The pullup
    // configuration is only valid for lines configured as inputs.
    // If the line is not currently input the requested pullup
    // state will take effect only if the line is later changed
    // to be an input line.
    aa_gpio_pullup(handle, AA_GPIO_MISO | AA_GPIO_MOSI);
    
    // Now reading the MISO line should give a logic high,
    // provided there is nothing attached to the Aardvark
    // adapter that is driving the pin low.
    val = aa_gpio_get(handle);
    if (val & AA_GPIO_MISO)
        printf("Read the MISO line as logic high (passive pullup)\n");
    else
        printf("Read the MISO line as logic low (is pin driven low?)\n");


    // Now do a 1000 gets from the GPIO to test performance
    {
        int i;
        for (i=0; i<1000; ++i) {
            aa_gpio_get(handle);
        }
    }

    {
        u08 oldval, newval;

        // Demonstrate use of aa_gpio_change
        aa_gpio_direction(handle, 0x00);
        oldval = aa_gpio_get(handle);

        printf("Calling aa_gpio_change for 2 seconds...\n");
        newval = aa_gpio_change(handle, 2000);

        if (newval != oldval)
            printf("  GPIO inputs changed.\n");
        else
            printf("  GPIO inputs did not change.\n");
    }

    // Turn on the I2C line pullups since we are done
    aa_i2c_pullup(handle, AA_I2C_PULLUP_BOTH);

    // Configure the Aardvark adapter back to SPI/I2C mode.
    aa_configure(handle, AA_CONFIG_SPI_I2C);
    
    // Close the device
    aa_close(handle);

    return 0;
}