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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GPIO输入模式，配置4个按键引脚为数字输入模式，KEY_UP按键配置下拉输入，
其余配置上拉输入，当按下按键后，翻转对应的LED。

Function descriptions:
This example demonstrates the GPIO input mode, where four key pins are configured
as digital input mode, and the KEY_UP button is configured as a pull-down input,
For other configurations, pull up the input and flip the corresponding LED when 
the button is pressed..
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测试环境：
测试用板：DPM32M087RBTx_EVB V1.0
MDK版本： 5.28

Test environment:
Test board: DPM32M087RBTx_EVB V1.0
MDK Version: 5.28
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使用步骤：
1. 编译下载程序到MCU，并运行；
2. 可观察当按键按下后，对应的LED灯翻转。

Example execution steps:
1. Compile and download the program to MCU, and run it.
2. It can be observed that when the button is pressed, the corresponding LED light
flips over.
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注意事项：
LED引脚如下：
LED1    -> PC10
LED2    -> PC11
LED3    -> PC12
LED4    -> PC13

按键引脚与对应LED关系如下：
KEY_UP  -> PC10    -> LED1
KEY1    -> PC11    -> LED2
KEY2    -> PC12    -> LED3
KEY3    -> PC13    -> LED4

Notes:
The LED pins are as follows:
LED1    -> PC10
LED2    -> PC11
LED3    -> PC12
LED4    -> PC13

The relationship between key pins and corresponding LEDs is as follows:
KEY_UP  -> PC10    -> LED1
KEY1    -> PC11    -> LED2
KEY2    -> PC12    -> LED3
KEY3    -> PC13    -> LED4
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