/**
  *************************************************************************************************************
  * @file     readme.txt
  * @brief    readme
  **************************************************************************
  */

  this demo is based on the ht32f49041_sk board, in this demo, pa8 output 47 khz
  waveforms, pa8 toggled each pa0, pa1, pa2 edge.
  pin connection:
  - pa0    <--->    pb0
  - pa1    <--->    pa6
  - pa2    <--->    pa7
