(1)蜂鸣器和弦音：电路原理图+示范代码

蜂鸣器和弦音电路原理

原理介绍：

BP_PWR控制三极管Q5控制蜂鸣器的供电，Q5开启后，给C6充电，此时Buzzer产生频率，蜂鸣器发声，音节快结束前，BP_PWR关闭Q5,此时蜂鸣器靠C6放电提供能量发声，实现拖音和弦效果。

以下是基于瑞萨单片机实现代码：

<code>/********************************************************************************
 文件:Beep.c
 功能:蜂鸣器和弦音，定义三种音，关机，开机，单音
 Author:电子颜工
 Time:2013.10.15
 Recent Modify:2013.10.16
 ******************************************************************************/

/*=======================以下是音调定义======================*/
#define Tone_C6  1
#define Tone_CS6 2
#define Tone_D6  3
#define Tone_DS6 4
#define Tone_E6  5
#define Tone_F6  6
#define Tone_FS6 7
#define Tone_G6  8
#define Tone_GS6 9
#define Tone_A6  10
#define Tone_AS6 11
#define Tone_B6  12

#define Tone_C7  13
#define Tone_CS7 14
#define Tone_D7  15 

#define Tone_DS7 16
#define Tone_E7  17
#define Tone_F7  18
#define Tone_FS7 19
#define Tone_G7  20
#define Tone_GS7 21
#define Tone_A7  22
#define Tone_AS7 23
#define Tone_B7  24

#define END 0//音频结束位 

#define SYS_FREQ  8  // MHZ 系统时钟
#define TIMER_CNT_BASE 1000000*SYS_FREQ/2  //定时器计数基数

#define BUZZER_IO      \t\tP3_bit.no1\t\t//BEEP IO
#define BUZZER_OUT   \t\tPM3_bit.no1=0\t//Mode OUT
#define BUZZER_PULL \t\tPU3_bit.no1=1\t//Pull up

#define PWR_CTRL         \tP13_bit.no0      //蜂鸣器供电控制脚

#define BUZZERIO_INIT {BUZZER_OUT;BUZZER_PULL;}
/*=========================音调频率表=======================*/
const uint Tune_Tbl[24]=
{
\t//C6,CS6, D6  ,DS6 ,E6  F6   ,FS6 ,G6  ,GS6 ,A6  ,AS6 ,B6
\t1047,1109,1175,1245,1319,1397,1480,1568,1661,1760,1865,1976,
\t//C7,CS7, D7  ,DS7 ,E7  F7   ,FS7 ,G7  ,GS7 ,A7  ,AS7 ,B7
\t2093,2217,2349,2489,2637,2794,2960,3136,3322,3520,3729,3951,
};
/*======================关机和弦1,2,3...====================*/
const uchar Sound_ShutDown[10]=\t  
{
 \tTone_C7,2,14,Tone_D7,2,6,Tone_E7,6,60,END
};
/*======================开机和弦3,2,1...====================*/

const uchar Sound_PowerOn[10]=\t  
{
\tTone_E7,2,6,Tone_D7,2,14,Tone_C7,6,60,END
};
/*======================单音和弦2...=======================*/
const uchar Sound_Single[10]=\t  
{
\tTone_D7,12,60,END,END,END,END,END,END,END,
}; 



#define S_SHUTDOWN 1//关机音
#define S_POWERON  2//开机音
#define S_SINGLE   3//单音

const uchar (*pSoundSel)[10];//选曲指针


struct BE
{
  uint  CountFR;\t//定时器计数值，通过改变计数值改变音频频率
  uchar PWR_time; \t//开启时间,单位为10mS
  uchar FREQ_time; \t//音频供给时间,单位为10mS
  uchar index;   \t//
}Beep;
volatile union { uchar flag4; __BITS8 flag4_bit; };
#define Beep_EN   \t\t\t\tflag4_bit.no0
#define Beep_Finish            flag4_bit.no1 //和弦结束标志

/*=======================================================
函数名:Beep_On(uchar SoundSel)
传入参数:SoundSel
功能:选择声音种类
调用:外部调用
=========================================================*/
__callt void Beep_On(uchar SoundSel)
{
\t\tBeep_EN=1;
\t\tBeep.index=0;
\t\tBeep_Finish=0;
\t\t
 \tswitch(SoundSel)
\t\t{
\t\t\tcase S_SHUTDOWN:
\t\t\t\t\tpSoundSel=&Sound_ShutDown;
\t\t\t\t
 \t\t\tbreak;
\t\t\tcase S_POWERON:
\t\t\t\t
\t\t\t\t\tpSoundSel=&Sound_PowerOn;
\t\t\t\t
\t\t\t\tbreak; 

\t\t\tcase S_SINGLE:
\t\t\t\t
\t\t\t\t\tpSoundSel=&Sound_Single;
\t\t\t\t
\t\t\t\tbreak;
\t\t\tdefault:
\t\t\t\tbreak;
\t\t}
\t
}
/*=======================================================
函数名:Beep_set()
功能:蜂鸣器参数设置
调用:Beep_control()
=========================================================*/
__callt void Beep_set()
 {   
   if ((*pSoundSel)[Beep.index]!=END)
    {
\t 
\t  Beep.CountFR=(uint)(TIMER_CNT_BASE/Tune_Tbl[(*pSoundSel)[Beep.index]-1]);
\t \t
\t  Beep.PWR_time=(*pSoundSel)[Beep.index+1];
\t  
\t  Beep.FREQ_time=(*pSoundSel)[Beep.index+2];
\t  
      Beep.index=Beep.index+3;
\t
\t}else {Beep.index=0; PWR_CTRL=1;Beep_EN=0;Beep_Finish=1;}
   return;
 }

/*=======================================================
函数名:Beep_control()
功能:蜂鸣器控制
调用:每10ms调用一次
=========================================================*/
__callt void Beep_control()//每10mS调用一次
{
\t
  if (Beep_EN)
     {
\t 
   if (Beep.PWR_time) 
   \t{
   \t\tPWR_CTRL=0;//供电\t
   \t\tBeep.PWR_time--; 

\t}
   else 
     {
     \tPWR_CTRL=1;//掉电,依靠电容放电实现和弦拖音 \t
\t    
\t }
   
   if (Beep.FREQ_time)
   \t{
   \t\tBeep.FREQ_time--;
\t \tCR000=Beep.CountFR;
  \t\tTOC00=0x03;   
  \t\t//TMC00=0X0C;//启动操作  
   \t}
\telse 
\t{
\t   \tTOC00=0x02;
\t\t//TMC00=0X00;//启动操作
\t   \tBeep_set();
\t\tPWR_CTRL=0;//发声完毕，打开电源给电容充电\t
\t}
\t}
\telse
\t{
\t  BUZZER_IO=0;
\t  TOC00=0x02;
\t
\t }
  return;
}
/<code>

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