51 microcontroller and buzzer realize Morse code conversion

Specific function implementation

When we press different keys in the matrix keys, the corresponding content is displayed on the LCD1602. Pressing a key multiple times at the same time can switch to different letters or numbers, and the LED light will flash. Finally, when we press confirm, the buzzer will sound with different frequencies.

device

Buzzer, AT89C51, several buttons, LCD1602, two LED lights, resistor

Simulation display diagram

Before simulation

After simulation

Knowledge introduction

Matrix button control principle

If independent buttons are used to connect to the microcontroller, each button requires an I/O port of the microcontroller. If a microcontroller system requires more buttons, using independent buttons will occupy too many I/O port resources. I/O port resources are often precious in single-chip microcomputer systems. In order to reduce I/O port pins when multiple buttons are used, matrix buttons are introduced.

Matrix key detection principle

Key detection is generally implemented by scanning. First, a certain column becomes low level, and the remaining columns are high level, and then it is detected whether a low level appears in each row. If it does not appear, it means that a certain row of keys has not been pressed. If it appears, it means that the key has been pressed and the position can be locked.

Matrix button control method

①Determinant method:

In the above picture, all the first columns are set to 0, and the remaining positions are all 1.

Set all the first rows to 0, and set all other bits to 1.

Therefore, we can conclude that the button pressed is exactly the first row and first column.

② Line flipping method:

First, set all rows to 0, then detect whether the column contains a low level, and if so, record the position of the column; then flip it, set all columns to 0, detect whether the row has a low level, and if so, record The position of the row (this article uses the line flipping method)

Main function code (C language) KEIL5 implementation

#include

#include

void delay(unsigned char ms);

void delay2(int i);

void lcd_wcmd(unsigned char cmd);

void lcd_pos(unsigned char pos);

void lcd_wdat(unsigned char dat);

void lcd_init();

void xianshi();

void KeyDown();

void la_ba();

sbit rs= P2^6;

sbit rw = P2^5;

sbit ep = P2^7;

sbit d=P3^0;

sbit d1=P3^1;

sbit lb=P3^2;

int b,c,s=0,q=0,w=0;

#define GPIO_KEY P1

unsigned char dis1[32];

unsigned char dis2[9]={',','A','D','G','J','M','P','T','W'};

unsigned char dis3[9]={'1','2','3','4','5','6','7','8','9'};

unsigned int code laba[36][5]={

1,2,3,3,3,//A

2,1,1,1,3,//B

2,1,2,1,3,//C

2,1,1,3,3,//D

1,3,3,3,3,//E

1,1,2,1,3,//F

2,2,1,3,3,//G

1,1,1,1,3,//H

1,1,3,3,3,//I

1,2,2,2,3,//J

2,1,2,3,3,//K

1,2,1,1,3,//L

2,2,3,3,3,//M

2,1,3,3,3,//N

2,2,2,3,3,//0

1,2,2,1,3,//P

2,2,1,2,3,//Q

1,2,1,3,3,//R

1,1,1,3,3,//S

2,3,3,3,3,//T

1,1,2,3,3,//U

1,1,1,2,3,//V

1,2,2,3,3,//W

2,1,1,2,3,//X

2,1,2,2,3,//Y

2,2,1,1,3,//Z

2,2,2,2,2,//0

1,2,2,2,2,//1

1,1,2,2,2,//2

1,1,1,2,2,//3

1,1,1,1,2,//4

1,1,1,1,1,//5

2,1,1,1,1,//6

2,2,1,1,1,//7

2,2,2,1,1,//8

2,2,2,2,1,//9

};

//LCD1602 code starts

bit lcd_bz()

{

bit result;

rs = 0;

rw = 1;

ep = 1;

_nop_();

_nop_();

_nop_();

_nop_();

result = (bit)(P0 & 0x80);

ep = 0;

return result;

}

void lcd_wcmd(unsigned char cmd)

{

while(lcd_bz());//Determine whether the LCD is busy

rs = 0;

rw = 0;

ep = 0;

_nop_();

_nop_();

P0 = cmd;

_nop_();

_nop_();

_nop_();

_nop_();

ep = 1;

_nop_();

_nop_();

_nop_();

_nop_();

ep = 0;

}

void lcd_pos(unsigned char pos)

{

lcd_wcmd(pos | 0x80);

}

void lcd_wdat(unsigned char dat)

{

while(lcd_bz());//Determine whether the LCD is busy

rs = 1;

rw = 0;

ep = 0;

P0 = that;

_nop_();

_nop_();

_nop_();

_nop_();

ep = 1;

_nop_();

_nop_();

_nop_();

_nop_();

ep = 0;

}

void lcd_init()

{

lcd_wcmd(0x38);

delay(1);

lcd_wcmd(0x0c);

delay(1);

lcd_wcmd(0x06);

delay(1);

lcd_wcmd(0x01);

delay(1);

}

void xianshi()

{

int i=0,j=1,n=0;

while(dis1[i] != '')

{

lcd_pos(0x00);//Set the display position

while(j!=0&&dis1[i] != '')

{

lcd_wdat(dis1[i]);//Display characters

i++;

j=i%16;

}

lcd_pos(0x40);//Set the display position

j=1;

while(j!=0&&dis1[i] != '')

{

lcd_wdat(dis1[i]);//Display characters

i++;

j=i%16;

}

j=1;

if(dis1[i] != '')

i-=16;

}

i=0;

}

//LCD1602 code ends

void delay(unsigned char ms)

{

unsigned char i;

while(ms--)

{

for(i = 0; i< 250; i++)

{

_nop_();

_nop_();

_nop_();

_nop_();

}

}

}

void delay2(int i)

{

while(i--);

}

//Press the button

void KeyDown()

{

int KeyValue=0;

GPIO_KEY=0x0f;

if(GPIO_KEY!=0x0f)

{

delay(5); //Debounce

if(GPIO_KEY!=0x0f)

{

GPIO_KEY=0X0F;

switch(GPIO_KEY)

{

case(0X07): KeyValue=0;break;

case(0X0b): KeyValue=1;break;

case(0X0d): KeyValue=2;break;

case(0X0e): KeyValue=12;break;

}

}

GPIO_KEY=0XF0;

switch(GPIO_KEY)

{

case(0X70): KeyValue=KeyValue;break;

case(0Xb0): KeyValue=KeyValue+3;break;

case(0Xd0): KeyValue=KeyValue+6;break;

case(0Xe0): KeyValue=KeyValue+9;break;

}

while(GPIO_KEY!=0xf0);

if(KeyValue!=c&&dis1[w]!='')

{b=0;w++;}

if(KeyValue<=8&&s==0)

{

if(c==12||c==15)w--;

dis1[w]=dis2[KeyValue]+b;

d=0;delay(25);d=1;delay(25);

}

else if(KeyValue<=8&&s==1)

{

if(c==12||c==15)w--;

dis1[in]=dis3[KeyValue];

d=0;delay(25);d=1;delay(25);

}

else if(KeyValue==12)

{

//When the key is 12, delete one digit (backspace)

if(w>0)

{

In--;

dis1[w]=' ';

}

else

{

dis1[w]=' ';

}

d1=0;delay(25);d1=1;delay(25);

}

else if(KeyValue==15)

{

//When 15 is pressed, add a space

while(w!=0)

{

In--;

dis1[w]=' ';

}

}

else if(KeyValue==9)

{

//display number 7

q++;

s=q%2;

if(c==12||c==15)w-=2;

}

else if(KeyValue==10)

{

//display number 8

if(s==0)

dis1[w]=' ';

else

dis1[w]='0';

}

else if(KeyValue==11)

{

//display number 9

dis1[w]=' ';

}

else if(KeyValue==18)

{

dis1[w]=' ';

In--;

}

else if(KeyValue==21)

{

la_ba();

}

b++;

if(b==3)b=0;

c=KeyValue;

}

}

//buzzer

void la_ba()

{

int i,j,t;

for(i=0;dis1[i]!='';i++)

{

if(dis1[i]>=65&&dis1[i]<=90)

{

d1=0;delay(25);d1=1;delay(25);

for(j=0;laba[dis1[i]-65][j]!=3;j++)

{

if(laba[dis1[i]-65][j]==1)

{

t=100;

while(t--)

{

lb=~lb;

delay2(70);

}

delay(50);

}

if(laba[dis1[i]-65][j]==2)

{

t=300;

while(t--)

{

lb=~lb;

delay2(70);

}

delay(50);

}

if(laba[dis1[i]-65][j+1]==3)

{

delay(100);

}

}

}

if(dis1[i]>=48&&dis1[i]<=57)

{

d=0;delay(25);d=1;delay(25);

for(j=0;j<5;j++)

{

if(laba[dis1[i]-22][j]==1)

{

t=100;

while(t--)

{

lb=~lb;

delay2(70);

}

delay(50);

}

if(laba[dis1[i]-22][j]==2)

{

t=300;

while(t--)

{

lb=~lb;

delay2(70);

}

delay(50);

}

if(j==4)

{

delay(100);

}

}

}

}

}

void main()

{

lcd_init();//Initialize LCD

delay(10);

while(1)

{

KeyDown();

xianshi();

}

}