视觉暂留，编程从一个I/O口输出一扫频信号，驱动一支LED灯闪动，频率范围为10HZ~99HZ，扫描时间为30秒，在LED闪动期间观察，一旦发现无法识别LED灯...

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视觉暂留，编程从一个I/O口输出一扫频信号，驱动一支LED灯闪动，频率范围为10HZ~99HZ，扫描时间为30秒，在LED闪动期间观察，一旦发现无法识别LED灯闪动时，按下按键K1，立即停止输出，并将此时的信号频率显示在数码管上，该信号的周期为测试者的视觉暂留时间。-Persistence of vision, programming from an I/O port outputs a sweep signal to drive an LED light flashing, the frequency range of 10HZ ~ 99HZ, scan time of 30 seconds, the LED flashing during the observation, once found it impossible to identify the LED lights flashing, press the key K1, immediate cessation of the output, and at this time the signal frequency displayed on the digital control on the test cycle of the signal" s persistence of vision time.