/**
  **************************************************************************
  * @file     readme.txt
  * @version  v2.0.3
  * @date     2022-02-11
  * @brief    readme
  **************************************************************************
  */

  this demo is based on the at-start board, in this demo, shows how to configure
  the tmr1 peripheral to a base interrupt. when systermclock/19200/10000 =
  1hz will generater overflow interrupt and toggle led3.
