/*!
    \file    main.c
    \brief   standby wakeup through RTC alarm interrupt

    \version 2021-12-30, V1.0.0, firmware for GD32F403
*/

/*
    Copyright (c) 2021, GigaDevice Semiconductor Inc.

    Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice, this
       list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.
    3. Neither the name of the copyright holder nor the names of its contributors
       may be used to endorse or promote products derived from this software without
       specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
OF SUCH DAMAGE.
*/

#include "gd32f403.h"
#include "gd32f403z_eval.h"
#include "systick.h"
#include "main.h"

void led_config(void);
void rtc_configuration(void);

/*!
    \brief      main function
    \param[in]  none
    \param[out] none
    \retval     none
*/
int main(void)
{
    systick_config();
    /* LED configuration and turn on all LEDs */
    led_config();
    gd_eval_led_on(LED2);
    gd_eval_led_on(LED3);
    gd_eval_led_on(LED4);
    gd_eval_led_on(LED5);
    /* delay 2s */
    delay_1ms(2000);
    /* enable PMU clock */
    rcu_periph_clock_enable(RCU_PMU);
    /* configure RTC */
    rtc_configuration();
    /* PMU enters standby mode */
    pmu_to_standbymode();

    while(1) {
    }
}

/*!
    \brief      configure LEDs
    \param[in]  none
    \param[out] none
    \retval     none
*/
void led_config(void)
{
    gd_eval_led_init(LED2);
    gd_eval_led_init(LED3);
    gd_eval_led_init(LED4);
    gd_eval_led_init(LED5);
}

/*!
    \brief      configure the RTC
    \param[in]  none
    \param[out] none
    \retval     none
*/
void rtc_configuration(void)
{
    /* enable BKPI clock */
    rcu_periph_clock_enable(RCU_BKPI);
    /* allow access to backup domain */
    pmu_backup_write_enable();
    /* reset backup domain */
    bkp_deinit();

    /* enable IRC40K */
    rcu_osci_on(RCU_IRC40K);
    /* wait till IRC40K is ready */
    rcu_osci_stab_wait(RCU_IRC40K);
    /* select RCU_IRC40K as RTC clock source */
    rcu_rtc_clock_config(RCU_RTCSRC_IRC40K);
    /* enable RTC clock */
    rcu_periph_clock_enable(RCU_RTC);

    /* wait for RTC registers synchronization */
    rtc_register_sync_wait();
    /* wait until last write operation on RTC registers has finished */
    rtc_lwoff_wait();
    /* enable the RTC alarm interrupt */
    rtc_interrupt_enable(RTC_INT_ALARM);
    /* wait until last write operation on RTC registers has finished */
    rtc_lwoff_wait();
    /* set RTC prescaler: set RTC period to 1s */
    rtc_prescaler_set(40000);
    /* wait until last write operation on RTC registers has finished */
    rtc_lwoff_wait();
    rtc_counter_set(0U);
    /* wait until last write operation on RTC registers has finished */
    rtc_lwoff_wait();
    rtc_alarm_config(ALARM_TIME_INTERVAL);
    /* wait until last write operation on RTC registers has finished */
    rtc_lwoff_wait();
    /* clear the RTC alarm flag */
    rtc_flag_clear(RTC_FLAG_ALARM);
}
