ARM开发7.5.1 基础实训( 5 ) 4×4 矩阵键盘和 2 路 LED 显示系统( 1)--LPC21XX

运行效果:
启动仿真,每当按键被按一次,在二个数码 LED 上显示某个按键的编号

一:仿真图

二:代码详情

#include"LPC21xx.h"
//常量定义
const unsigned char LEDSEGCODE [] =
{
    0x3F , 0x06 , 0x5B , 0x4F , 0x66 , 0x6D , 0x7D , 0x07 , 0x7F , 0x6F ,
    0x77 , 0x7C , 0x39 , 0x5e , 0x79 , 0x71 , 0x00 , 0x40
};
//这一个对应P0.14,P0.15为位选
const unsigned char LEDBITCODE [] = { 0xB0 , 0x70 };//  1110 0000  0000 ==>8  1101 0000  0000==>9                   1011 0000  0000 0000==>14   0111 0000 0000 0000==>15
//书上用的这一个,位选端口也要改为P0.8  P0.9
//const unsigned char LEDBITCODE [] = { 0x0E , 0x0D };
unsigned char LEDBuffer [ 2 ] = { 0x00 , 0x01 };
unsigned char KSCANCODE [] = { 0x01 , 0x02 , 0x04 , 0x08 };
unsigned char keytab [ 4 ][ 4 ] =
{
    0x00 , 0x01 , 0x02 , 0x03 , 0x04 , 0x05 , 0x06 , 0x07 , 0x08 , 0x09 , 0x00 , 0x01 , 0x02 , 0x03 ,
    0x04 , 0x05
};
void Delay_250us(void)//延时函数
{
    unsigned int i ;
    i=2500 ;// CCLK=60MHz
    while ( i-- );
}
unsigned char LEDScanpointer , DATApointer ;
int main ( void )
{
//变量定义
    unsigned char keyval ;
    unsigned char row , col ;
    unsigned int i ;
    unsigned int j=0 ;
    PINSEL0=0x00000000 ;
    PINSEL1=0x00000000 ;
	  //书上是这个，如果选用P0.14,P0.15为位选是不行的因为P0.14,Po.15未为输出模式
	  //IO0DIR=0x00000FFF;
    IO0DIR=0x0000FFFF ;//P0.14,P0.15为位选
    IO1DIR=0x000F0000 ;// KR1~KR4 定义为输出 KC1~KC4 定义为输入
    IO0CLR=0x00000F00 ;//初始化 LED7 灭
    IO0SET=0x000000FF ;
    LEDScanpointer=0 ;
    DATApointer=0 ;
    keyval=0 ;
//无限循环体
    while ( 1 )
    {
        if ( j==0 )
        {
//从 P0.8~P0.11 读入端口电平 //P0.8~p0.15
            for ( row=0 ; row<4 ; row++ )
            {
                IO1SET= ( 0x0F ) <<16 ;
                IO1CLR= ( KSCANCODE [ row ]) <<16 ;
                if (( IO1PIN&0x00F00000 ) !=0x00F00000 )//检测到键盘按下动作
                {
                    Delay_250us(); //延时去抖动
                    if (( IO1PIN&0x00F00000 ) !=0x00F00000 ) //确认是哪个键盘按下
                    {
                        if (( IO1PIN&0x00E00000 ) ==0x00E00000 ) col=0 ;
                        else if (( IO1PIN&0x00D00000 ) ==0x00D00000 ) col=1 ;
                        else if (( IO1PIN&0x00B00000 ) ==0x00B00000 ) col=2 ;
                        else col=3 ;
                        keyval=keytab [ row ][ col ];
                        for ( i= ( sizeof ( LEDBuffer ) -1 ); i>0 ; i-- )
                            LEDBuffer [ i ] =LEDBuffer [ i-1 ];
                        LEDBuffer [ 0 ] =keyval ;
                        j=20 ;
                    }
                }
            }
        }
        LEDScanpointer=0 ;
        while ( LEDScanpointer<sizeof ( LEDBuffer ))
        {
            IO0CLR|=0xFF ;//段码全部熄灭
            IO0SET|= ( LEDSEGCODE [ LEDBuffer [ LEDScanpointer ]] <<0 );
            IO0CLR|=0xFF00 ;//位码全部熄灭
            IO0SET|= ( LEDBITCODE [ LEDScanpointer ] <<8);//确定位输出
            LEDScanpointer++ ;
            Delay_250us();//调用延时函数
        }
        for ( i=0 ; i<10 ; i++ ) Delay_250us();
        if ( j !=0 ) j-- ;
    }
}

三:运行效果