/**
  **************************************************************************
  * @file     readme.txt 
  * @version  v2.0.5
  * @date     2022-05-20
  * @brief    readme
  **************************************************************************
  */

  this demo is based on the at-start board, in this demo, systick interrupt
  per milisecond and led2 fresh per 200 ms.for more detailed information. 
  please refer to the application note document AN0083.
