PWC — 深度睡眠 + RTC 唤醒

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#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"

void rtc_config(void)
{
  exint_init_type exint_init_struct;

  /* config the exint line of the rtc alarm */
  exint_init_struct.line_select   = EXINT_LINE_17;
  exint_init_struct.line_enable   = TRUE;
  exint_init_struct.line_mode     = EXINT_LINE_INTERRUPT;
  exint_init_struct.line_polarity = EXINT_TRIGGER_RISING_EDGE;
  exint_init(&exint_init_struct);

  /* enable the battery-powered domain write operations */
  pwc_battery_powered_domain_access(TRUE);

  /* reset battery-powered domain register */
  bpr_reset();

  /* enable the lick */
  crm_clock_source_enable(CRM_CLOCK_SOURCE_LICK, TRUE);

  /* wait lick is ready */
  while(crm_flag_get(CRM_LICK_STABLE_FLAG) == RESET);

  /* select the rtc clock source */
  crm_rtc_clock_select(CRM_RTC_CLOCK_LICK);

  /* enable rtc clock */
  crm_rtc_clock_enable(TRUE);

  /* wait for rtc registers update */
  rtc_wait_update_finish();

  /* set rtc divider: set rtc period to 1sec */
  rtc_divider_set(32767);

  /* wait for the register write to complete */
  rtc_wait_config_finish();

  /* enable alarm interrupt */
  rtc_interrupt_enable(RTC_TA_INT, TRUE);

  /* wait for the register write to complete */
  rtc_wait_config_finish();

  /* configure and enable rtc alarm interrupt */
  nvic_irq_enable(RTCAlarm_IRQn, 0, 0);
}

int main(void)
{
  crm_clocks_freq_type crm_clocks_freq_struct = {0};
  __IO uint32_t systick_index = 0;

  /* congfig the system clock */
  system_clock_config();
  
  /* get system clock */
  crm_clocks_freq_get(&crm_clocks_freq_struct);

  /* init at start board */
  at32_board_init();

  /* config priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  /* turn on the led light */
  at32_led_on(LED2);
  at32_led_on(LED3);
  at32_led_on(LED4);

  /* enable pwc and bpr clock */
  crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_BPR_PERIPH_CLOCK, TRUE);

  /* config rtc */
  rtc_config();

  while(1)
  {
    /* clear second flag */
    rtc_flag_clear(RTC_TS_FLAG);

    /* wait for the second flag to be set */
    while(rtc_flag_get(RTC_TS_FLAG) == RESET);

    /* set the wakeup time to 3 seconds */
    rtc_alarm_set(rtc_counter_get() + 3);

    /* wait for the register write to complete */
    rtc_wait_config_finish();

    at32_led_off(LED2);

    /* save systick register configuration */
    systick_index = SysTick->CTRL;
    systick_index &= ~((uint32_t)0xFFFFFFFE);

    /* disable systick */
    SysTick->CTRL &= (uint32_t)0xFFFFFFFE;

    /* congfig the voltage regulator mode */
    pwc_voltage_regulate_set(PWC_REGULATOR_LOW_POWER);

    /* enter deep sleep mode */
    pwc_deep_sleep_mode_enter(PWC_DEEP_SLEEP_ENTER_WFI);

    /* restore systick register configuration */
    SysTick->CTRL |= systick_index;
  
    /* wait 3 LICK(maximum 120us) cycles to ensure clock stable */
    /* when wakeup from deepsleep,system clock source changes to HICK */
    if((CRM->misc3_bit.hick_to_sclk == TRUE) && (CRM->misc1_bit.hickdiv == TRUE))
    {
      /* HICK is 48MHz */
      delay_us(((120 * 6 * HICK_VALUE) /crm_clocks_freq_struct.sclk_freq) + 1);
    }
    else
    {
      /* HICK is 8MHz */
      delay_us(((120 * HICK_VALUE) /crm_clocks_freq_struct.sclk_freq) + 1);
    }

    /* wake up from deep sleep mode, congfig the system clock */
    system_clock_recover();

    at32_led_on(LED2);
    delay_ms(500);
  }
}