Simple calculator based on 51 single chip microcomputer 12864-EEWORLD

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I finally wrote the calculator. Actually, I had written it a long time ago, but I was busy with exams and lab projects, so I didn't have time to write a blog. Now I am at home during the winter vacation, and I can finally learn something quietly.

Below I will first write about the process of writing this program. In fact, this is a final project for the microcontroller class, but few people can write it well. In fact, a calculator is very complicated to consider carefully. But we only need to make a simple calculator, so my calculator only has integer addition, subtraction, multiplication and division, and negative number function. After testing, it is still practical.

The overall idea of this program is very simple, and it mainly involves the processing of some details.

The idea is to first scan the matrix keyboard, monitor the operation symbols pressed, store the two operands, calculate the result, and display the whole process in real time.

First, matrix keyboard scanning. I used the method taught by Guo Tianxiang. This method is easy to understand, but the disadvantage is that the code is too long, so I went online to find a simple matrix keyboard scanning. (Compared to thinking hard, sometimes it is also good to go online to find methods)

void keyscan()

{

uchar h,l;

if(keypress())

{

P3=0X0F;

_nop_();

h=P3;

h&=0X0F; //Read the row where the key is located

P3=0XF0;

_nop_();

l=P3;

l&=0XF0; //Read the key column

key=h+l; //Finally add as the switch case selection

//This scanning process is very clear, right?

switch(key)

{

case 0xEE:key=1;Input[i]='1';break;// 1

case 0xDE:key=4;Input[i]='4';break;// 4

case 0xBE:key=7;Input[i]='7';break;// 7

case 0x7E:key=0;Input[i]='0';break; /// 0

case 0xED:key=2;Input[i]='2';break;// 2

case 0xDD:key=5;Input[i]='5';break;// 5

case 0xBD:key=8;Input[i]='8';break; // 8

case 0x7D:key=16;i--;break; // = 16

case 0xEB:key=3;Input[i]='3';break; // 3

case 0xDB:key=6;Input[i]='6';break; // 6

case 0xBB:key=9;Input[i]='9';break; // 9

case 0x7B: clear();break; // c 17

case 0xE7:key=18;Input[i]='+';n=i;break; // + 18

case 0xD7:key=19;Input[i]='-';n=i;break;// - 19

case 0xB7:key=20;Input[i]='*';n=i;break; // * 20

case 0x77:key=21;Input[i]='/';n=i;break; // / 21

default:key=22;

}

i++;

while(keypress());

}

My keyscan() function came out...

By storing the number of keys pressed each time into an array and then continuously displaying the array members, you can achieve the effect of displaying the input numbers in real time.

void jisuan(int n,int l,uchar yusuan)

{

int a=0,b=0,c=0,result;

uchar x;

for(x=0;x

{

a+=(Input[x]-'0')*pow(10,nx-1);

}

for(x=n+1;x

{

b+=(Input[x]-'0')*pow(10,lx-1);

}

// write_num(0,1,a);

// write_num(0,2,b);

switch(yusuan)

{

case '+':result=a+b;write_num(0,1,result); break; // + 18

case '-':result=ab;write_num(0,1,result);break;// - 19

case '*':result=a*b;write_num(0,1,result);break; // * 20

case '/':result=a/b;write_num(0,1,result);break; // / 21

}

This is the calculation function.

a+=(Input[x]-'0')*pow(10,nx-1);

b+=(Input[x]-'0')*pow(10,lx-1);

This is used to calculate the input value, which should be understandable

Finally, the main function:

void main()

{

Lcd_Init();

// write_string(0,3,"check ok");

while(1)

{

keyscan();

write_string(0,0,Input);

if(key==16)

{

l=i;

if(n>0&&n!=i-1)

{

switch(Input[n])

{

case '+':jisuan(n,l,'+'); break; // + 18

case '-':jisuan(n,l,'-');break;// - 19

case '*':jisuan(n,l,'*');break; // * 20

case '/':jisuan(n,l,'/');break; // / 21

}

else

{

write_string(0,1,"ERROR");

}

delayms(1);

}

while(1);

}

This is the end of the 51 program of the simple calculator

Reference address：Simple calculator based on 51 single chip microcomputer 12864

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