/*!
    \file  readme.txt
    \brief description of the calendar alarm example
    
    \version 2026-02-05, V1.3.0, firmware for gd32c2x1
*/

/*
    Copyright (c) 2026, 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.
*/

  This example is based on the GD32C231C-EVAL-V1.0 board, it explains how 
to configure the RTC module. In this demo, RTC peripheral is configured to keep
time and generate an alarm interrupt.
  
  The RTC clock source can be chose to LXTAL or IRC32K by uncomment the corresponding 
define in main file. And the HyperTerminal should be connected to the evaluation 
board via USART.
  
  After start-up, get key value from BKP data register or bit RTCSRC of RCU_CTL1 
 register. If the value is not correct, the program will ask to set the time and alarm
value on the HyperTerminal. If the key value is correct, the time and alarm value
will be displayed on the HyperTerminal. Also the demo shows how to get the current 
subsecond value and convert it into fractional format.
  
  Then LED1 is turned on.
  
  The RTC module is not reset by the system reset . 
  
  When the alarm interrupt generated, the LED1 toggled. The alarm is configured to 
occur once per minute.