51 MCU long key test program-EEWORLD

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#include

Program function: This program is used to test the 4X4 matrix keyboard; and has the ability to long press test.

When a key is pressed, the pressed key number is displayed on LCD1602, such as: K1 K2.... K16;

When a key is pressed for more than 1S, a key value is returned every 250MS, realizing the function of long pressing.

At the same time, the key value is sent to the port through the serial port for display;

Program Description: This is a traditional method of using delay to scan keys, drive keys and test programs; this method is

It is not used in actual project programming. It is used in teaching when students are just beginning to learn microcontrollers.

Note: In this program, only the long press of K4 is displayed. If you want to handle the long press of other keys, just add

Just handle the relevant ones.

Matrix keyboard pin definition

sbit keyin4 = P2^7;

sbit keyin3 = P2^6;

sbit keyin2 = P2^5;

sbit keyin1 = P2^4;

sbit keyout1 = P2^3;

sbit keyout2 = P2^2;

sbit keyout3 = P2^1;

sbit keyout4 = P2^0;

//Macro definition

#define TH0_NUM 1000 //Easy to transplant the program;

#define TL0_NUM 1000

bit Flag1s, Flag250Ms, Flag2Ms; //Time reached flag

//lcd1602 display array

unsigned char keynum[]="keynum:k ";

unsigned char keycount[3]="000";

//Key value query array

//k1,k2,k3,k4,k5,k6,k7,k8,

unsigned char code keytabel[]={0xe7,0xd7,0xb7,0x77,0xeb,0xdb,0xbb,0x7b,

//k9,k10,k11,k12,k13,k14,k15,k16,

0xed,0xdd,0xbd,0x7d,0xee,0xde,0xbe,0x7e};

External function declaration

extern void InitLcd1602();

extern void LcdShowStr(unsigned char x, unsigned char y, unsigned char *str);

void ConfigUART(unsigned int baud);

void DelayMs(unsigned int ms);

unsigned char keyscan();

void InitTimer0();

Main Program

void main()

{

unsigned char i,j,keytemp=0;

InitTimer0();

ConfigUART(9600);

InitLcd1602();

LcdShowStr(0,0,keynum);

while(1)

{

keytemp=keyscan();

if(keytemp!=0) //Judge whether a key is pressed;

{

for(i=0;i<16;i++) //When a key is pressed, look up the table to get the key value;

{

if(keytemp == keytabel[i])

break;

}

keynum[8]=(i+1)/10+0x30;

keynum[9]=(i+1)%10+0x30;

TI=1;

SBUF=keytemp;

while(TI!=1);

TI=0;

LcdShowStr(0,0,keynum);

if(keytemp==0x77) //Used to detect long press of up key K4, and display on the second line of LCD1602

{ //Add 1 every 250MS;

j++;

if(j>254)

j=0;

keycount[0] = j/100%10+0x30;

keycount[1] = j/10%10+0x30;

keycount[2] = j%10+0x30;

TI=1; //Used for serial port, print plus 1 every 250MS;

printf("key is long pushing %s \n",keycount);

while(TI!=1);

TI=0;

}

LcdShowStr(0,1,keycount);

}

Function: N milliseconds delay

void DelayMs(unsigned int ms)

{

unsigned int i,j;

for(i=0;i

for(j=0;j<113;j++);

}

Function: Matrix keyboard scanning (with long key detection function)

unsigned char keyscan()

{

static unsigned char num1,temp;

P2 = 0xf0;

num1=P2;

if(num1!=0xf0)

{

DelayMs(50);

num1=P2;

if(num1!=0xf0)

{

TR0=1; //Turn on the timer

temp=num1;//

P2 = 0x0f;

DelayMs(1);

num1=P2;

temp =temp|num1;

{

P2 = 0xf0;

num1=P2;

if(Flag1s == 1) // Check if the key is pressed for 1S;

{

if(Flag250Ms==1) //If you don't release the key within 1S, it means you have long pressed a key; then return every 250MS

{ //One key value; this implements the function of long pressing a key

Flag250Ms=0;

return temp;

}

while(num1!=0xf0);

}

else

{

TR0=0; //If not pressed, turn off the timer

Flag1s=0;

Flag250Ms=0;

temp=0;

}

else

{

TR0=0;

Flag1s=0;

Flag250Ms=0;

temp = 0;

}

TR0=0; //When you let go, you should also turn off the timer and clear several flags;

Flag1s=0;

Flag250Ms=0;

return temp;

}

Function: Initialize timer 0 and set it to interrupt once every 1MS

void InitTimer0()

{

TMOD &=0xf0; //This operation mode will not destroy other settings of the register;

TMOD |= 0x01; //Mode 1, 16-bit timer

TH0/=(65536-TH0_NUM)/256;

TL0=(65536-TL0_NUM)%256;

EA=1;

ET0=1;

TR0=0;

}

Function: Timer 0 interrupt service routine

void Timer0_Interrupt() interrupt 1

{

static unsigned char i,j,k;

TH0=(65536-TH0_NUM)/256;

TL0=(65536-TL0_NUM)%256;

i++;j++;

if(i>2)

{

i=0;

Flag2Ms=1;

}

if(j==250)

{

j=0;

Flag250Ms=1;

k++;

if(k==4)

{

k=0;

Flag1s=1;

}

Reference address：51 MCU long key test program

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