8051内部定时计数器，按计数器模式和方式1工作，对P3.4（T0）引脚进行计数，使用8051的T1作定时器，50ms中断一次，看T0内每50ms来了多少脉冲，将计数值送显（通过LED发光二极管8421码来表示），1秒后再次测试。-8051 internal timer counter by counter mode and manner of a work, the P3.4 (T0) pin counts, using 8051-T1 for the timer, 50ms interrupt time, look T0 every 50ms to the number of pulses, the count value send significant (8421 yards through the LED light-emitting diode), one second after the test again.