wenkong_junshi/Examples/USART/Half_duplex_transmitter&receiver

/*!
\file readme.txt
\brief description of the USART HalfDuplex

\version 2017-02-10, V1.0.0, firmware for GD32F30x
\version 2018-10-10, V1.1.0, firmware for GD32F30x
\version 2018-12-25, V2.0.0, firmware for GD32F30x
\version 2020-09-30, V2.1.0, firmware for GD32F30x
*/

/*
Copyright (c) 2020, GigaDevice Semiconductor Inc.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its contributors
may be used to endorse or promote products derived from this software without
specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
OF SUCH DAMAGE.
*/

This demo is based on the GD32307C-EVAL-V1.1 board, it provides a basic communication
USART0 whith USART1 in Half-Duplex mode.
The transmitter_buffer0 and transmitter_buffer1 are sent by USART0 and USART1 respectively and
displayed in HyperTerminal. If the data received by USART0 is equal to transmitter_buffer1, LED2
is turned on. If the data received by USART1 is equal to transmitter_buffer0, LED3 is turned on.

connect USART0_Tx(PA9) to USART1_Tx(PA2)