原创 PWM实现蜂呜器唱歌

PWM用定时器0作时钟源可改变频率，用于输出音符频率，占空比输出音符音长

电路图：

BUZZ.C

/*

 * 文 件 名：BUZZ.C

 * 芯    片：STC12C5A60S2

 * 晶    振：12MHz

 * 创 建 者：冷月

 * 创建日期：2010.9.1

 * 修 改 者：

 * 修改日期：

 * 功能描述：利用STC单片机的PWM使蜂呜器演奏乐曲

 *                  PWM用定时器0作时钟源可改变频率，用于输出音符频率，占空比输出音符音长

 */

#include <STC12C5A.H>

#include <string.h>

#include "Delay.h"

#include "PCA.H"

#include "Music.h"

#include "key.h"

#define    uchar      unsigned char

#define    uint  unsigned int

//低音频率音符表，中音=低音*2，高音=低音*4

uint code lowSoundFreTab[12] =

{

       262,

       277,

       293,

       311,

       329,

       349,

       370,

       392,

       415,

       440,

       466,

       494,

};

//标准音符在频率音符表位置，freTabXY[0]不用，

uchar freTabXY[8] =

{

       0, 0, 2, 4, 5, 7, 9, 11,

};

//几分音符 = 2^n，n为数组下标

uchar noteLenTab[7] =

{

       1, 2, 4, 8, 16, 32, 64,

};

//根据演奏调号和演奏音区生成新的频率音符表

uint newSoundFreTab[12];

//一分音符的音长约为160ms

#define    ONE_NOTE_LEN 160

//四分音符的音长约为

#define    FOUR_NOTE_LEN      ONE_NOTE_LEN/4

//函数原型申明

void PlayMusic(uchar *music, uchar startFre, uchar upDownTone);

void CreatNewFreTab(uchar startFre, uchar upDownTone);

uint GetTone(uchar tone);

uint Getlen(uchar noteLen, uint *length);

/*

 * 函 数 名：main

 * 功能描述：程序入口

 * 输入参数：无

 * 返 回 值：无

 */

void main(void)

{

       InitTimer1();

       PCA_Init(1, PWM, 0x80, 0x80, CLK2);

       InitTimer0();

       while (1)

       {

              switch (theMusic)

              {

                     case 0:

                            PlayMusic(laoHu, 3, 0);

                            break;

                     case 1:

                            PlayMusic(girl, 0, 0);

                            break;

                     case 2:

                            PlayMusic(sameSong, 0, 0);

                            break;

                     case 3:

                            PlayMusic(twoButterfly, 0, 0);

                            break;

                     case 4:

                            PlayMusic(qiuTian, 7, 0);

                            break;

                     case 5:

                            PlayMusic(lvHua, 2, 0);

                            break;

                     case 6:

                            PlayMusic(woHeNi, 2, 0);

                            break;

                     case 7:

                            PlayMusic(xingYue, 4, 0);

                            break;

                     case 8:

                            PlayMusic(juHua, 7, 0);

                            break;

              }

              DelayMs1T(1000);

       }

}

/*

 * 函 数 名：PlayMusic

 * 功能描述：播放一首歌曲

 * 输入参数：music：歌曲数组

 *                  startFre：起始调,0～11；

 *                  upDownTone：升降调，1-降8度，2-不变，3-升8度

 * 返 回 值：无

 */

void PlayMusic(uchar *music, uchar startFre, uchar upDownTone)

{

       uint musicPos = 0;                //当前播放歌曲位置

       uint musicLen = 0;               //歌曲长度

       uint fre;                               //音符频率

       uint length;                          //音符长度

       uint len1;                             //音符发音时长

       uint len2;                                   //音符不发音时长

       uchar i;

       CreatNewFreTab(startFre, upDownTone);

       while (music[musicLen] != 0)                            //计算歌曲长度，即有多少音符

       {

              musicLen += 2;

       }

       while (musicPos < musicLen)

       {

              fre = GetTone(music[musicPos]);                              //音符频率

              len1 = Getlen(music[musicPos+1], &length);      //音符发音时长

              len2 = length - len1;                                                //音符不发音时长

              Set_PWM_Fre(fre);

              Set_PWM1(50);                                               //发音

              for (i=0; i<len1; i++)

              {

                     DelayMs1T(10);

              }

              Set_PWM1(0);                                                 //不发音

              for (i=0; i<len2; i++)

              {

                     DelayMs1T(10);

              }

              musicPos += 2;                                                //指向下一个音符

              if (keyFlag == 1)                 //有按键按下

              {

                     keyFlag = 0;

                     return;

              }

       }

}

/*

 * 函 数 名：CreatNewFreTab

 * 功能描述：根据演奏调号和演奏音区生成新的频率音符表

 * 输入参数：startFre：起始调,0～11；

 *                  upDownTone：升降调，1-降8度，2-不变，3-升8度

 * 返 回 值：无

 */

void CreatNewFreTab(uchar startFre, uchar upDownTone)

{

       uchar i, j;

       for (i=0; i<12; i++)

       {

              j = i + startFre;

              if (j < 12)

              {

                     newSoundFreTab = lowSoundFreTab[j];