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                                样例使用说明
                             Sample Description
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功能描述：
此样例演示了使用TIM1产生“六步PWM信号”，每间隔1ms在SysTick中断中触发换向，实现无刷
电机的换向。

Function descriptions:
This example demonstrates the use of TIM1 to generate a "six step PWM signal", 
which triggers commutation in the SysTick interrupt every 1ms to achieve 
commutation of a brushless motor.
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测试环境：
测试用板：PY32T020_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: PY32T020_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. 编译下载程序到MCU，并运行
2. 使用逻辑分析仪观察引脚PA3/PA7/PA5/PB0/PA4/PB1的波形

Example execution steps:
1. Compile and download the program to MCU and run it
2. Use Logic analyzer to observe the waveform of pin PA3/PA7/PA5/PB0/PA4/PB1
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注意事项：
换向步骤和波形如下所示：
                第一步  第二步  第三步  第四步  第五步  第六步     
CH1               1       0       0      0        0       1        
CH1N              0       0       1      1        0       0        
CH2               0       0       0      1        1       0        
CH2N              1       1       0      0        0       0        
CH3               0       1       1      0        0       0        
CH3N              0       0       0      0        1       1        

CH1  (PA03)   |||||||_________________________________|||||||
CH1N (PA07)   _______________||||||||||||||||________________
                                  
CH2  (PA05)   _______________________||||||||||||||||________
CH2N (PB00)   |||||||||||||||________________________________
                                  
CH3  (PA04)   _______||||||||||||||||________________________
CH3N (PB01)   ________________________________|||||||||||||||

Notes:
The commutation steps and waveforms are as follows:
                Step1   Step2   Step3   Step4   Step5   Step6
CH1               1       0       0      0        0       1        
CH1N              0       0       1      1        0       0        
CH2               0       0       0      1        1       0        
CH2N              1       1       0      0        0       0        
CH3               0       1       1      0        0       0        
CH3N              0       0       0      0        1       1        

CH1  (PA03)   |||||||_________________________________|||||||
CH1N (PA07)   _______________||||||||||||||||________________
                                  
CH2  (PA05)   _______________________||||||||||||||||________
CH2N (PB00)   |||||||||||||||________________________________
                                  
CH3  (PA04)   _______||||||||||||||||________________________
CH3N (PB01)   ________________________________|||||||||||||||

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