/*!
    \file  readme.txt
    \brief description of the timestamp example

    \version 2024-01-05, V1.2.0, firmware for GD32H7xx
*/

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  This demo is based on the GD32H759I-EVAL-V1.1 board, it explains how 
to use the timestamp function of RTC. In this demo, RTC peripheral is configured to keep
time and generate the timestamp 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. The vbat bin on the board should connect to the CR1220 battery.
The tamper key is the timestamp pin.

  After start-up,get key value from BKP data register or bit RTCSRC of backup domain 
control register. If the value is not correct, the program will ask to set the time value 
on the HyperTerminal. If the key value is correct, the current time and subsecond value
will be displayed on the HyperTerminal. 

  Then LED1 is turned on.

  The RTC module is in the Backup Domain, and is not reset by the system reset or 
power reset. 

  When press the tamper key, a timestamp interrupt will be generated, the current time
then be print on the HyperTerminal, and LED1 toggles.
