text: /**
   * Copyright (c) 2015 - 2018, Nordic Semiconductor ASA
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   *
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   *    Semiconductor ASA integrated circuit in a product or a software update for
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   * 4. This software, with or without modification, must only be used with a
   *    Nordic Semiconductor ASA integrated circuit.
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  /** @file
   *
   * @defgroup low_power_pwm_example_main main.c
   * @{
   * @ingroup low_power_pwm_example
   * @brief Low Power PWM Example Application main file.
   *
   *
   */
  
  #include <stdbool.h>
  #include <stdint.h>
  #include "nrf_delay.h"
  #include "nrf_gpio.h"
  #include "boards.h"
  #include "app_error.h"
  #include "sdk_errors.h"
  #include "app_timer.h"
  #include "nrf_drv_clock.h"
  #include "app_util_platform.h"
  #include "low_power_pwm.h"
  #include "nordic_common.h"
  
  /*Ticks before change duty cycle of each LED*/
  #define TICKS_BEFORE_CHANGE_0   500
  #define TICKS_BEFORE_CHANGE_1   400
  
  static low_power_pwm_t low_power_pwm_0;
  static low_power_pwm_t low_power_pwm_1;
  static low_power_pwm_t low_power_pwm_2;
  
  /**
   * @brief Function to be called in timer interrupt.
   *
   * @param[in] p_context     General purpose pointer (unused).
   */
  static void pwm_handler(void * p_context)
  {
      uint8_t new_duty_cycle;
      static uint16_t led_0, led_1;
      uint32_t err_code;
      UNUSED_PARAMETER(p_context);
  
      low_power_pwm_t * pwm_instance = (low_power_pwm_t*)p_context;
  
      if (pwm_instance->bit_mask == BSP_LED_0_MASK)
      {
          led_0++;
  
          if (led_0 > TICKS_BEFORE_CHANGE_0)
          {
              new_duty_cycle = pwm_instance->period - pwm_instance->duty_cycle;
              err_code = low_power_pwm_duty_set(pwm_instance, new_duty_cycle);
              led_0 = 0;
              APP_ERROR_CHECK(err_code);
          }
      }
      else if (pwm_instance->bit_mask == BSP_LED_1_MASK)
      {
          led_1++;
  
          if (led_1 > TICKS_BEFORE_CHANGE_1)
          {
              new_duty_cycle = pwm_instance->period - pwm_instance->duty_cycle;
              err_code = low_power_pwm_duty_set(pwm_instance, new_duty_cycle);
              led_1 = 0;
              APP_ERROR_CHECK(err_code);
          }
      }
      else
      {
          /*empty else*/
      }
  }
  /**
   * @brief Function to initalize low_power_pwm instances.
   *
   */
  
  static void pwm_init(void)
  {
      uint32_t err_code;
      low_power_pwm_config_t low_power_pwm_config;
  
      APP_TIMER_DEF(lpp_timer_0);
      low_power_pwm_config.active_high    = false;
      low_power_pwm_config.period         = 220;
      low_power_pwm_config.bit_mask       = BSP_LED_0_MASK;
      low_power_pwm_config.p_timer_id     = &lpp_timer_0;
      low_power_pwm_config.p_port         = NRF_GPIO;
  
      err_code = low_power_pwm_init((&low_power_pwm_0), &low_power_pwm_config, pwm_handler);
      APP_ERROR_CHECK(err_code);
      err_code = low_power_pwm_duty_set(&low_power_pwm_0, 20);
      APP_ERROR_CHECK(err_code);
  
      APP_TIMER_DEF(lpp_timer_1);
      low_power_pwm_config.active_high    = false;
      low_power_pwm_config.period         = 200;
      low_power_pwm_config.bit_mask       = BSP_LED_1_MASK;
      low_power_pwm_config.p_timer_id     = &lpp_timer_1;
      low_power_pwm_config.p_port         = NRF_GPIO;
  
      err_code = low_power_pwm_init((&low_power_pwm_1), &low_power_pwm_config, pwm_handler);
      APP_ERROR_CHECK(err_code);
      err_code = low_power_pwm_duty_set(&low_power_pwm_1, 150);
      APP_ERROR_CHECK(err_code);
  
      APP_TIMER_DEF(lpp_timer_2);
      low_power_pwm_config.active_high    = false;
      low_power_pwm_config.period         = 100;
      low_power_pwm_config.bit_mask       = BSP_LED_2_MASK;
      low_power_pwm_config.p_timer_id     = &lpp_timer_2;
      low_power_pwm_config.p_port         = NRF_GPIO;
  
      err_code = low_power_pwm_init((&low_power_pwm_2), &low_power_pwm_config, pwm_handler);
      APP_ERROR_CHECK(err_code);
      err_code = low_power_pwm_duty_set(&low_power_pwm_2, 20);
      APP_ERROR_CHECK(err_code);
  
      err_code = low_power_pwm_start((&low_power_pwm_0), low_power_pwm_0.bit_mask);
      APP_ERROR_CHECK(err_code);
      err_code = low_power_pwm_start((&low_power_pwm_1), low_power_pwm_1.bit_mask);
      APP_ERROR_CHECK(err_code);
      err_code = low_power_pwm_start((&low_power_pwm_2), low_power_pwm_2.bit_mask);
      APP_ERROR_CHECK(err_code);
  }
  
  static void lfclk_init(void)
  {
      uint32_t err_code;
      err_code = nrf_drv_clock_init();
      APP_ERROR_CHECK(err_code);
  
      nrf_drv_clock_lfclk_request(NULL);
  }
  
  /**
   * @brief Function for application main entry.
   */
  int main(void)
  {
      uint8_t new_duty_cycle;
      uint32_t err_code;
  
      lfclk_init();
  
      // Start APP_TIMER to generate timeouts.
      err_code = app_timer_init();
      APP_ERROR_CHECK(err_code);
  
      /*Initialize low power PWM for all 3  channels of RGB or 3 channels of leds on pca10028*/
      pwm_init();
  
      while (true)
      {
          /* Duty cycle can also be changed from main context. */
          new_duty_cycle = low_power_pwm_2.period - low_power_pwm_2.duty_cycle;
          err_code = low_power_pwm_duty_set(&low_power_pwm_2, new_duty_cycle);
          APP_ERROR_CHECK(err_code);
          nrf_delay_ms(500);
  
          new_duty_cycle = low_power_pwm_2.period - low_power_pwm_2.duty_cycle;
          err_code = low_power_pwm_duty_set(&low_power_pwm_2, new_duty_cycle);
          APP_ERROR_CHECK(err_code);
          nrf_delay_ms(500);
      }
  }
  
  /** @} */
  