/*!
    \file    main.c
    \brief   RTC calendar 
    
    \version 2017-02-10, V1.0.0, firmware for GD32F403
    \version 2018-12-25, V2.0.0, firmware for GD32F403
    \version 2020-09-30, V2.1.0, firmware for GD32F403
*/

/*
    Copyright (c) 2020, 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 "rtc.h"
#include <stdio.h>

uint32_t RTCSRC_FLAG = 0; 
/*!
    \brief      main function
    \param[in]  none
    \param[out] none
    \retval     none
*/
int main(void)
{
    /* COM0 config */
    gd_eval_com_init(EVAL_COM0);

    /* NVIC config */
    nvic_configuration();

    printf( "\r\n This is a RTC demo...... \r\n" );

    /* get RTC clock entry selection */
    RTCSRC_FLAG = GET_BITS(RCU_BDCTL, 8, 9);
    
    if ((0xA5A5 != bkp_read_data(BKP_DATA_0)) || (0x00 == RTCSRC_FLAG)){
        /* backup data register value is not correct or not yet programmed
        or RTC clock source is not configured (when the first time the program 
        is executed or data in RCU_BDCTL is lost due to Vbat feeding) */
        printf("\r\nThis is a RTC demo!\r\n");
        printf("\r\n\n RTC not yet configured....");

        /* RTC configuration */
        rtc_configuration();

        printf("\r\n RTC configured....");

        /* adjust time by values entred by the user on the hyperterminal */
        time_adjust();

        bkp_write_data(BKP_DATA_0, 0xA5A5);
    }else{
        /* check if the power on reset flag is set */
        if (rcu_flag_get(RCU_FLAG_PORRST) != RESET){
            printf("\r\n\n Power On Reset occurred....");
        }else if (rcu_flag_get(RCU_FLAG_SWRST) != RESET){
            /* check if the software reset flag is set */
            printf("\r\n\n Software Reset occurred....");
        }

        /* allow access to BKP domain */
        rcu_periph_clock_enable(RCU_PMU);
        pmu_backup_write_enable();

        printf("\r\n No need to configure RTC....");
        /* wait for RTC registers synchronization */
        rtc_register_sync_wait();

        /* enable the RTC second */
        rtc_interrupt_enable(RTC_INT_SECOND);

        /* wait until last write operation on RTC registers has finished */
        rtc_lwoff_wait();
    }

#ifdef RTCCLOCKOUTPUT_ENABLE
    /* enable PMU and BKPI clocks */
    rcu_periph_clock_enable(RCU_BKPI);
    rcu_periph_clock_enable(RCU_PMU);
    /* allow access to BKP domain */
    pmu_backup_write_enable();

    /* disable the tamper pin */
    bkp_tamper_detection_disable();

    /* enable RTC clock output on tamper Pin */
    bkp_rtc_calibration_output_enable();
#endif

    /* clear reset flags */
    rcu_all_reset_flag_clear();

    /* display time in infinite loop */
    time_show();

    while (1){
    }
}

/* retarget the C library printf function to the USART */
int fputc(int ch, FILE *f)
{
    usart_data_transmit(EVAL_COM0, (uint8_t)ch);
    while(RESET == usart_flag_get(EVAL_COM0, USART_FLAG_TBE));

    return ch;
}
