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                                样例使用说明
                             Sample Description
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功能描述：
此样例演示了USART的中断方式发送和接收数据。USART被配置为115200波特率，8位数据位，1位
停止位，无校验位。下载并运行程序后，上位机通过USART会接收到0x1-0xC的数据，并将其再次
通过USART发送回去。

Function descriptions:
This sample demonstrates the interrupt-based transmission and reception of 
data using USART. The USART is configured with a baud rate of 115200, 8 data 
bits, 1 stop bit, and no parity. After downloading and running the program, 
the host computer will receive data from 0x1 to 0xC via USART, and then send 
the received data back to the MCU via USART.
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测试环境：
测试用板：PY32M020_STK
MDK版本： 5.28
IAR版本： 9.20
GCC版本： GNU Arm Embedded Toolchain 10.3-2021.10

Test environment:
Test board: PY32M020_STK
MDK Version: 5.28
IAR Version: 9.20
GCC Version: GNU Arm Embedded Toolchain 10.3-2021.10
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使用步骤：
1. 编译并下载程序到MCU；
2. 通过USB转TTL模块连接PC与STK板,STK板与USB转TTL模块的连线方式如下；
STK板        USB转TTL模块
PA09(TX) --> RX
PA10(RX) --> TX
GND      --> GND
3. PC端打开串口调试助手，正确连接上通讯COM口，波特率设置为115200；
4. MCU会发送0x1~0xc到PC端；
5  上位机接收后. 上位机发送12个数据，MCU会反馈同样的12个数据给上位机。

Example execution steps:
1.Compile and download the program to the MCU.
2.Connect the PC and STK board using a USB-to-TTL module. The connection is 
as follows:
STK board USB-to-TTL module
PA09(TX) --> RX
PA10(RX) --> TX
GND --> GND
3.Open a serial debugging assistant on the PC and connect to the appropriate 
COM port with a baud rate of 115200.
4.The MCU will send 0x1 to 0xC to the host computer.
5.Upon receiving the data, the host computer will send the same 12 data back 
to the MCU.
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注意事项：

Notes:
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