基于單片機的簡易電子琴設計(電路+程序)

ID:459745 · 發表于 2019-1-2 14:16

電路圖如下：

#include <reg51.h>

#define uint unsigned int

#define uchar unsigned char

#define output P1

#define input P1

//方便移植在其他電路板上，我的電路使用P1口做鍵盤輸入接口

//定義16個按鍵

enum KEY{key0,key1,key2,key3,key4,key5,key6,key7,key8,key9,key10,key11,key12,key13,key14,key15};

uchar code table[]={  //數組定義,顯示數碼管

0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71,0x00};

unsigned int code Freqtab[] = {  //定時半周期的初始值

64021,64103,64260,64400, //低音3 4 5 6

64524,64580,64684,64777, //低音7,中音1 2 3

64820,64898,64968,65030, //中音4 5 6 7

65058,65110,65157,65178}; //高音1 2 3 4

uint FreqTemp;

//蜂鳴器聲音不怎么樣，我們使用揚聲器，接P3.7口

sbit SPEAK = P3^7;

void delay1ms(uint n) //誤差 0us ,延時n毫秒

{

uint a,b,c;

for(c=n;c>0;c--)

for(b=199;b>0;b--)

for(a=1;a>0;a--);

}

uint key_input(void)

{

uchar temp1,temp2; //臨時保存讀取的行或者列

uchar num = 16; //返回按鍵的值

output = 0x0f;

temp1 = input; //先讀取行

if(0x0f != temp1)  //按鍵按下

{

delay1ms(5); //延時，消除抖動

temp1 = input; //再次讀取行

if(0x0f != temp1) //說明按鍵確實按下

{

temp1 = temp1 & 0x0f; //保留低4位

output = 0xf0; //準備讀取列

delay1ms(1); //延時一下，防止下一句讀不到

temp2 = input; //直接讀取列

temp2 = temp2 & 0xf0; //保留高4位

temp1 = temp1 | temp2; //將temp1和temp2的值合并

}

}

switch(temp1)

{

case 0xee:num=0;break;

case 0xde:num=1;break;

case 0xbe:num=2;break;

case 0x7e:num=3;break;

case 0xed:num=4;break;

case 0xdd:num=5;break;

case 0xbd:num=6;break;

case 0x7d:num=7;break;

case 0xeb:num=8;break;

case 0xdb:num=9;break;

case 0xbb:num=10;break;

case 0x7b:num=11;break;

case 0xe7:num=12;break;

case 0xd7:num=13;break;

case 0xb7:num=14;break;

case 0x77:num=15;break;

default:break;

}

return num;

}

void T0_INT(void) interrupt 1

{

TL0 = FreqTemp; //載入定時半周期的初始值

TH0 = FreqTemp >> 8;

SPEAK = ~SPEAK; //發音

}

int main()

{

TMOD = 0X01; //定時器T0設置為方式1

EA = 1;

ET0 = 1;

TR0 = 0;

while(1)

{

uint num,temp;

num = key_input();

temp = num;

P0 = table[num];

if(16 != num)

{

FreqTemp = Freqtab[num];

TR0 = 1;

while(0xf0 != output); //檢測按鍵松開

TR0 = 0;

SPEAK = 1;

}

}

return 0;

}