参考程序:
#include "reg51.h"
#include "intrins.h"
sfr P0M1 = 0x93;
sfr P0M0 = 0x94;
sfr P1M1 = 0x91;
sfr P1M0 = 0x92;
sfr P2M1 = 0x95;
sfr P2M0 = 0x96;
sfr P3M1 = 0xb1;
sfr P3M0 = 0xb2;
sfr P4M1 = 0xb3;
sfr P4M0 = 0xb4;
sfr P5M1 = 0xC9;
sfr P5M0 = 0xCA;
sfr P6M1 = 0xCB;
sfr P6M0 = 0xCC;
sfr P7M1 = 0xE1;
sfr P7M0 = 0xE2;
bit FLAG; //1:上升沿中断 0:下降沿中断
sbit P10 = P1^0;
void exint0() interrupt 0//INT0中断入口
{
P10 = !P10; //将测试口取反
FLAG = INT0;//保存INT0口的状态, INT0=0(下降沿); INT0=1(上升沿)
}
void main()
{
P0M0 = 0x00;
P0M1 = 0x00;
P1M0 = 0x00;
P1M1 = 0x00;
P2M0 = 0x00;
P2M1 = 0x00;
P3M0 = 0x00;
P3M1 = 0x00;
P4M0 = 0x00;
P4M1 = 0x00;
P5M0 = 0x00;
P5M1 = 0x00;
P6M0 = 0x00;
P6M1 = 0x00;
P7M0 = 0x00;
P7M1 = 0x00;
INT0 = 1;
IT0 = 0;//设置INT0的中断类型 (1:仅下降沿 0:上升沿和下降沿)
EX0 = 1; //使能INT0中断
EA = 1;
while (1);
}