ChibiOS Free Embedded RTOS

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

static void pwmpcb(PWMDriver *pwmp)
{
  (void)pwmp;
  palClearPad(GPIOD, GPIOD_LED5);
}

static void pwmc1cb(PWMDriver *pwmp)
{
  (void)pwmp;
  palSetPad(GPIOD, GPIOD_LED5);
}

static PWMConfig pwmcfg = {
  10000,                                    /* 10kHz PWM clock frequency.   */
  10000,                                    /* Initial PWM period 1S.       */
  pwmpcb,
  {
   {PWM_OUTPUT_ACTIVE_HIGH, pwmc1cb},
   {PWM_OUTPUT_DISABLED, NULL},
   {PWM_OUTPUT_DISABLED, NULL},
   {PWM_OUTPUT_DISABLED, NULL}
  },
  0,
  0
};

icucnt_t last_width, last_period;

static void icuwidthcb(ICUDriver *icup)
{
  palTogglePad(GPIOD, GPIOD_LED4);
  last_width = icuGetWidth(icup);
}

static void icuperiodcb(ICUDriver *icup)
{
  last_period = icuGetPeriod(icup);
}

static ICUConfig icucfg = {
  ICU_INPUT_ACTIVE_HIGH,
  10000,                                    /* 10kHz ICU clock frequency.   */
  icuwidthcb,
  NULL, //icuperiodcb, // without the period cb, the widht cb does NOT get called in 2.6.3???
  NULL,
  ICU_CHANNEL_1,
  0
};

/*
 * 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();

  /*
   * Initializes the PWM driver 2 and ICU driver 3.
   * GPIOA15 is the PWM output.
   * GPIOC6 is the ICU input.
   * The two pins have to be externally connected together.
   */
  pwmStart(&PWMD2, &pwmcfg);
  palSetPadMode(GPIOA, 15, PAL_MODE_ALTERNATE(1));
  icuStart(&ICUD3, &icucfg);
  palSetPadMode(GPIOC, 6, PAL_MODE_ALTERNATE(2));
  icuEnable(&ICUD3);
  chThdSleepMilliseconds(2000);

  /*
   * Starts the PWM channel 0 using 75% duty cycle.
   */
  pwmEnableChannel(&PWMD2, 0, PWM_PERCENTAGE_TO_WIDTH(&PWMD2, 7500));
  chThdSleepMilliseconds(5000);

  /*
   * Changes the PWM channel 0 to 50% duty cycle.
   */
  pwmEnableChannel(&PWMD2, 0, PWM_PERCENTAGE_TO_WIDTH(&PWMD2, 5000));
  chThdSleepMilliseconds(5000);

  /*
   * Changes the PWM channel 0 to 25% duty cycle.
   */
  pwmEnableChannel(&PWMD2, 0, PWM_PERCENTAGE_TO_WIDTH(&PWMD2, 2500));
  chThdSleepMilliseconds(5000);

  /*
   * Changes PWM period to half second the duty cycle becomes 50%
   * implicitly.
   */
  pwmChangePeriod(&PWMD2, 5000);
  chThdSleepMilliseconds(5000);

  /*
   * Disables channel 0 and stops the drivers.
   */
  pwmDisableChannel(&PWMD2, 0);
  pwmStop(&PWMD2);
  icuDisable(&ICUD3);
  icuStop(&ICUD3);
  palClearPad(GPIOD, GPIOD_LED4);
  palClearPad(GPIOD, GPIOD_LED5);

  /*
   * Normal main() thread activity, in this demo it does nothing.
   */
  while (TRUE) {
    chThdSleepMilliseconds(500);
  }
  return 0;
}