remote-control-translator-firmware/src/main.c

/*
 * Remote Control Translator Firmware
 * Copyright (C) 2017 Clayton G. Hobbs <clay@lakeserv.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
    ChibiOS - Copyright (C) 2006..2016 Giovanni Di Sirio

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

#include <stdbool.h>

#include "ch.h"
#include "hal.h"

/* PWM configuration for IR output */
static PWMConfig pwmcfg = {
    380000, /* 380 kHz PWM clock frequency. */
    10, /* PWM period 10 clock cycles.   */
    NULL,
    {
        {PWM_OUTPUT_ACTIVE_HIGH, NULL},
        {PWM_OUTPUT_DISABLED, NULL},
        {PWM_OUTPUT_DISABLED, NULL},
        {PWM_OUTPUT_DISABLED, NULL}
    },
    0,
    0
};

/* Timer configuration for IR output */
static const GPTConfig gpt4cfg = {
  1000000, // 1 MHz timer clock.
  NULL, // No callback
  0, 0
};

/*
 * Green LED blinker thread, times are in milliseconds.
 */
static THD_WORKING_AREA(waThread1, 128);
static THD_FUNCTION(Thread1, arg) {

    (void)arg;
    while (true) {
        palClearPad(GPIOC, GPIOC_LED);
        chThdSleepMilliseconds(500);
        palSetPad(GPIOC, GPIOC_LED);
        chThdSleepMilliseconds(500);
    }
}

/*
 * Synchronously send one bit for RC5
 */
void rc5_bit(bool bit)
{
    if (bit) {
        pwmDisableChannel(&PWMD1, 0);
        gptPolledDelay(&GPTD4, 889);
        pwmEnableChannel(&PWMD1, 0, PWM_PERCENTAGE_TO_WIDTH(&PWMD1, 5000));
        gptPolledDelay(&GPTD4, 889);
    } else {
        pwmEnableChannel(&PWMD1, 0, PWM_PERCENTAGE_TO_WIDTH(&PWMD1, 5000));
        gptPolledDelay(&GPTD4, 889);
        pwmDisableChannel(&PWMD1, 0);
        gptPolledDelay(&GPTD4, 889);
    }
}

/*
 * Synchronously send a whole RC5 frame
 */
void rc5_frame(bool toggle, int addr, int data)
{
    /* Start */
    rc5_bit(1);
    rc5_bit(1);
    /* Toggle */
    rc5_bit(toggle);
    /* Address */
    for (int b = 0x10; b != 0; b >>= 1) {
        rc5_bit(addr & b);
    }
    /* Data */
    for (int b = 0x20; b != 0; b >>= 1) {
        rc5_bit(data & b);
    }
}

/*
 * Application entry point.
 */
int main(void) {

    /*
     * System initializations.
     * - HAL initialization, this also initializes the configured device drivers
     *   and performs the board-specific initializations.
     * - Kernel initialization, the main() function becomes a thread and the
     *   RTOS is active.
     */
    halInit();
    chSysInit();

    /*
     * Creates the blinker thread.
     */
    chThdCreateStatic(waThread1, sizeof(waThread1), NORMALPRIO, Thread1, NULL);

    /* Configure PWM */
    pwmStart(&PWMD1, &pwmcfg);
    palSetPadMode(GPIOA, 8, PAL_MODE_STM32_ALTERNATE_PUSHPULL);

    /* Configure GPT */
    gptStart(&GPTD4, &gpt4cfg);

    /* Send a continuous stream of power off signals to the TV */
    while (true) {
        rc5_frame(false, 0x00, 0x0C);

        chThdSleepMilliseconds(90);
    }
}