給個例子，也許可以滿足妳的要求：
#include?"reg51.h"
#define?FOSC?12000000L
#define?T1XXH?(65536-FOSC/12*?2/1000)?+2//?2ms?timer?calculation?method?in?12T?mode
#define?T1XXL?(65536-FOSC/12*?8/1000)//?8ms?timer?calculation?method?in?12T?mode
/*?define?SFR?*/
sbit?TEST_100Hz?=?P1^0;//?100Hz?Out
/*?Timer1?interrupt?routine?*/
void?tm1_isr()?interrupt?3?using?1
{
TEST_100Hz?=?!?TEST_100Hz;
if(TEST_100Hz)?{
TL1?+=?T1XXH;?//reload?timer1?low?byte
TH1?=?T1XXH?>>?8;//reload?timer1?high?byte
}
else?{
TL1?+=?T1XXL;?//reload?timer1?low?byte
TH1?=?T1XXL?>>?8;//reload?timer1?high?byte
}
}
//-----------------------------------------------
/*?main?program?*/
void?main()
{
TMOD?=?0x10;//set?timer1?as?mode1?(16-bit)
TL1?=?T1XXH;?//initial?timer1?low?byte
TH1?=?T1XXH?>>?8;//initial?timer1?high?byte
TEST_100Hz=1;TR1?=?1;//timer1?start?running
ET1?=?1;//enable?timer1?interrupt
EA?=?1;?//open?global?interrupt?switch
while?(1);?//loop
}