AT32F415_Firmware_Library/project/at_start_f415/examples/usart/rs485

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

  this demo is based on the at-start board and AT32-Comm-EV, in this demo, 
  shows how to use usart to achieve rs485 communication.
  
  set-up
  - usart tx      --->   pa2
  - usart rx      --->   pa3
  - usart de      --->   pa1