-51单片机例程源码之-用PCA实现定时器.zip.zip

//用PCA实现定时器 #include "STC12C5A.H" #include "intrins.h" #define FOSC 24000000L #define T100Hz (FOSC/12/100) //100Hz,10ms typedef unsigned char BYTE; typedef unsigned int WORD; sbit PCA_LED = P0^0; BYTE count=0; WORD value; //PCA中断服务程序 void PCA_ISR() interrupt 7 using 1 { CCF0 = 0; //清中断标志 CCAP0L = value; CCAP0H = value>>8; //更新比较值 value += T100Hz; if(count++ == 100) //定时1S { count = 0; PCA_LED = !PCA_LED; //取反LED } } //主函数 void main(void) { CCON = 0; //初始化PCA控制寄存器,PCA定时器关闭，清CF标志，清中断标志 CL = 0; //复位 PCA base timer CH = 0; CMOD = 0x00; //PCA时钟源: FOSC/12,关闭PCA定时器溢出中断 value = T100Hz; CCAP0L = value; //初始化PCA模块0 CCAP0H = value>>8; value += T100Hz; CCAPM0 = 0x49; //16位定时器模式，使能PCA中断 CR = 1; //使能PCA定时器 EA = 1; //开总中断 while(1); }