请各位帮我讲解一下下面的程序.
#ifndef __SOUNDPLAY_H_REVISION_FIRST__
#define __SOUNDPLAY_H_REVISION_FIRST__
//**************************************************************************
#define SYSTEM_OSC 12000000 //定义晶振频率12000000HZ
#define SOUND_SPACE 4/5 //定义普通音符演奏的长度分率,//每4分音符间隔
sbit BeepIO = P3^7; //定义输出管脚
unsigned int code FreTab[12] = { 262,277,294,311,330,349,369,392,415,440,466,494 }; //原始频率表
unsigned char code SignTab[7] = { 0,2,4,5,7,9,11 }; //1~7在频率表中的位置
unsigned char code LengthTab[7]= { 1,2,4,8,16,32,64 };
unsigned char Sound_Temp_TH0,Sound_Temp_TL0; //音符定时器初值暂存
unsigned char Sound_Temp_TH1,Sound_Temp_TL1; //音长定时器初值暂存
//**************************************************************************
void InitialSound(void)
{
BeepIO = 0;
Sound_Temp_TH1 = (65535-(1/1200)*SYSTEM_OSC)/256; // 计算TL1应装入的初值 (10ms的初装值)
Sound_Temp_TL1 = (65535-(1/1200)*SYSTEM_OSC)%256; // 计算TH1应装入的初值
TH1 = Sound_Temp_TH1;
TL1 = Sound_Temp_TL1;
TMOD |= 0x11;
ET0 = 1;
ET1 = 0;
TR0 = 0;
TR1 = 0;
EA = 1;
}
void BeepTimer0(void) interrupt 1 //音符发生中断
{
BeepIO = !BeepIO;
TH0 = Sound_Temp_TH0;
TL0 = Sound_Temp_TL0;
}
//**************************************************************************
void Play(unsigned char *Sound,unsigned char Signature,unsigned Octachord,unsigned int Speed)
{
unsigned int NewFreTab[12]; //新的频率表
unsigned char i,j;
unsigned int Point,LDiv,LDiv0,LDiv1,LDiv2,LDiv4,CurrentFre,Temp_T,SoundLength;
unsigned char Tone,Length,SL,SH,SM,SLen,XG,FD;
for(i=0;i<12;i++) // 根据调号及升降八度来生成新的频率表
{
j = i + Signature;
if(j > 11)
{
j = j-12;
NewFreTab = FreTab[j]*2;
}
else
NewFreTab = FreTab[j];
if(Octachord == 1)
NewFreTab>>=2;
else if(Octachord == 3)
NewFreTab<<=2;
}
SoundLength = 0;
while(Sound[SoundLength] != 0x00) //计算歌曲长度
{
SoundLength+=2;
}
Point = 0;
Tone = Sound[Point];
Length = Sound[Point+1]; // 读出第一个音符和它时时值
LDiv0 = 12000/Speed; // 算出1分音符的长度(几个10ms)
LDiv4 = LDiv0/4; // 算出4分音符的长度
LDiv4 = LDiv4-LDiv4*SOUND_SPACE; // 普通音最长间隔标准
TR0 = 0;
TR1 = 1;
while(Point < SoundLength)
{
SL=Tone%10; //计算出音符
SM=Tone/10%10; //计算出高低音
SH=Tone/100; //计算出是否升半
CurrentFre = NewFreTab[SignTab][SL-1]+SH]; //查出对应音符的频率
if(SL!=0)
{
if (SM==1) CurrentFre >>= 2; //低音
if (SM==3) CurrentFre <<= 2; //高音
Temp_T = 65536-(50000/CurrentFre)*10/(12000000/SYSTEM_OSC);//计算计数器初值
Sound_Temp_TH0 = Temp_T/256;
Sound_Temp_TL0 = Temp_T%256;
TH0 = Sound_Temp_TH0;
TL0 = Sound_Temp_TL0 + 12; //加12是对中断延时的补偿
}
SLen=LengthTab[Length%10]; //算出是几分音符
XG=Length/10%10; //算出音符类型(0普通1连音2顿音)
FD=Length/100;
LDiv=LDiv0/SLen; //算出连音音符演奏的长度(多少个10ms)
if (FD==1)
LDiv=LDiv+LDiv/2;
if(XG!=1)
if(XG==0) //算出普通音符的演奏长度
if (SLen<=4)
LDiv1=LDiv-LDiv4;
else
LDiv1=LDiv*SOUND_SPACE;
else
LDiv1=LDiv/2; //算出顿音的演奏长度
else
LDiv1=LDiv;
if(SL==0) LDiv1=0;
LDiv2=LDiv-LDiv1; //算出不发音的长度
if (SL!=0)
{
TR0=1;
for(i=LDiv1;i>0;i--) //发规定长度的音
{
while(TF1==0);
TH1 = Sound_Temp_TH1;
TL1 = Sound_Temp_TL1;
TF1=0;
}
}
if(LDiv2!=0)
{
TR0=0; BeepIO=0;
for(i=LDiv2;i>0;i--) //音符间的间隔
{
while(TF1==0);
TH1 = Sound_Temp_TH1;
TL1 = Sound_Temp_TL1;
TF1=0;
}
}
Point+=2;
Tone=Sound[Point];
Length=Sound[Point+1];
}
BeepIO = 0;
}
//**************************************************************************
#endif |
楼主
标题置顶
标题高亮
