#include <reg51f.h>
//調整軟件狗定時器
void watchdog_reset (void)
{
unsigned int newval;
newval  = (CH << 8) | CL;
newval += 0xFF00;
CCAP4L = newval;
CCAP4H = newval >> 8;
}
//MAIN C 
void main (void)
{
unsigned int i;
//確定溢出
watchdog_reset ();
CCAPM4 = 0x48;
//構造 PCA 
CMOD = (CMOD & 0x01) | 0x40;
//開始PCA定時器，每0xFF00滿即復位
CR = 1;
//等待
for (i = 0; i < 1000; i++)
         {
         watchdog_reset ();         
}