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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SCI的DMA方式发送和接收数据，SCI配置为115200，数据位8，停止位1，
校验位None,下载并运行程序后，打印提示信息，然后通过上位机下发12个数据，例如
0x1~0xC,则MCU会把接收到的数据再次发送到上位机，然后打印结束信息。

Function descriptions:
This example demonstrates how to use SCI to send an amount of data in DMA
mode. SCI configuration is 115200 baud rate, data bit 8, stop bit 1, check bit 
None. After download and run the program,Print the prompt message, and then send
12 data through the upper computer, such as 0x1~0xC, the MCU will send the 
received data to the upper computer again, Then print the end message 
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测试环境：
测试用板：PY32E407_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: PY32E407_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
TX(PA09) --> RX
RX(PA10) --> 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会发送信息到PC端，提示输入12个数据
5. 用上位机发送12个数据，MCU会反馈同样的12个数据给上位机,然后提示执行结束

Example execution steps:
1. compile and download the program to MCU and run it;
2. Connect the PC to the STK board through the USB-to-TTL module. The connection 
method between the STK board and the USB-to-TTL module is as follows.
STK board    USB-to-TTL module
TX(PA09) --> RX
RX(PA10) --> TX
GND      --> GND
3. Start the serial assistant on the PC, correctly connect the COM port, and set
the baud rate to 115200.
4. The MCU will send a message to the PC, prompting you to enter 12 data
5. The upper computer sends 12 data, and the MCU will feedback the same 12 data 
to the upper computer, and then prompt the execution to end
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注意事项：

Notes:

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