按列扫描

#include <REGX52.H>
#include "Delay.h"/*** @brief  矩阵键盘读取按键键码* @param  无* @retval KeyNumber 按下按键的键码值如果按键按下不放，程序会停留在此函数，松手的一瞬间，返回按键键码，没有按键按下时，返回0*/
unsigned char MatrixKey()
{unsigned char KeyNumber=0;P1=0xFF;P1_3=0;if(P1_7==0){Delay(20);while(P1_7==0);Delay(20);KeyNumber=1;}if(P1_6==0){Delay(20);while(P1_6==0);Delay(20);KeyNumber=5;}if(P1_5==0){Delay(20);while(P1_5==0);Delay(20);KeyNumber=9;}if(P1_4==0){Delay(20);while(P1_4==0);Delay(20);KeyNumber=13;}P1=0xFF;P1_2=0;if(P1_7==0){Delay(20);while(P1_7==0);Delay(20);KeyNumber=2;}if(P1_6==0){Delay(20);while(P1_6==0);Delay(20);KeyNumber=6;}if(P1_5==0){Delay(20);while(P1_5==0);Delay(20);KeyNumber=10;}if(P1_4==0){Delay(20);while(P1_4==0);Delay(20);KeyNumber=14;}P1=0xFF;P1_1=0;if(P1_7==0){Delay(20);while(P1_7==0);Delay(20);KeyNumber=3;}if(P1_6==0){Delay(20);while(P1_6==0);Delay(20);KeyNumber=7;}if(P1_5==0){Delay(20);while(P1_5==0);Delay(20);KeyNumber=11;}if(P1_4==0){Delay(20);while(P1_4==0);Delay(20);KeyNumber=15;}P1=0xFF;P1_0=0;if(P1_7==0){Delay(20);while(P1_7==0);Delay(20);KeyNumber=4;}if(P1_6==0){Delay(20);while(P1_6==0);Delay(20);KeyNumber=8;}if(P1_5==0){Delay(20);while(P1_5==0);Delay(20);KeyNumber=12;}if(P1_4==0){Delay(20);while(P1_4==0);Delay(20);KeyNumber=16;}return KeyNumber;
}

应用

#include <REGX52.H>
#include "LCD1602.h"
#include "Delay.h"
#include "MatrixKey.h"unsigned char KeyNum;void main(){LCD_Init();LCD_ShowString(1,1,"hello world!" );while(1){KeyNum=MatrixKey();if(KeyNum){LCD_ShowNum(2,1,KeyNum,2);}}}