文件名：timer2.c 功能：time2定时时间到后取反输出引脚RC0，定时时间由PORTB设置 硬件描述：PORTB接8位拔码开关作输入，RC0接示波器和频率计-File Name: timer2.c features: time2 time after the time to take counter output pin RC0, regular time set by the PORTB Hardware Descr iption: PORTB then 8-bit D