Analog Write

About

Write analog values to an analog output pin to form a sawtooth wave. Connect a LED to the analog output pin and watch the brightness of the LED change.

Source code

/**
 * @section License
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2017, Erik Moqvist
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * This file is part of the Simba project.
 */

#include "simba.h"

int main()
{
    int value;
    struct analog_output_pin_t pin;

    sys_start();
    analog_output_pin_module_init();

    /* Initialize the analog output pin. */
    analog_output_pin_init(&pin, &pin_d10_dev);

    value = 0;

    while (1) {
        /* Write a sawtooth wave to the analog output pin. */
        analog_output_pin_write(&pin, value);
        value += 5;
        value %= 1024;

        /* Wait ten milliseconds. */
        thrd_sleep_ms(10);
    }

    return (0);
}

The source code can also be found on Github in the examples/analog_write folder.

Build and run

Build and upload the application.

$ cd examples/analog_write
$ make -s BOARD=<board> upload