嵌入式应用系统设计课程论文模板

PAGE沈阳理工大学《嵌入式计算机产品案例》课程论文题目基于ARM的音频系统设计姓名王军超学号1203060433院别信息科学与工程专业通信工程2014年4月12日

1概述1.1嵌入式系统的技术背景

在许多领域中广泛应用的嵌入式计算系统(简称为嵌入式系统)，是在更大的电子器件中嵌入的重复完成特定功能的计算系统，它经常不被器件的使用者所识别，但在各种常用的电子器件中能够找到这些嵌入式系统。例如，消费类电子产品中的手机、寻呼机、数字相机、摄像机、录像机、个人数字助理等，家用电器中的微波炉、洗衣机、烤箱、门禁系统、照明系统等，商用装置中的卡片读入器、扫描仪、打印机等。1.2数字音频系统的应用数字音频信号是对模拟信号的一种量化，典型方法是对时间坐标按相等的时间间隔做采样，对振幅做量化。单位时间内的采样次数称为采样频率。这样一段声波就可以被数字化后变成一串数值，每个数值对应相应抽样点的振幅值，按顺序将这些数字排列起来就是数字音频信号了。这是ADC(模拟-数字转换)过程。DAC(数字-模拟转换)过程相反，将连续的数字按采样时候的频率顺序转换成对应的电压。2系统的硬件设计2.1系统设计方案音频ADC/DAC通俗一点来讲就是录音（音频ADC）和放音（音频DAC）。放音是数字音频信号转换成模拟音频信号，以推动耳机、功放等模拟音响设备，而录音则是要将麦克风等产生的模拟音频信号转换成数字音频信号，并最终转换成计算机可以处理的通用音频文件格式。2.2S3C2410的IIS模块S3C2410的IIS总线简介IIS总线是近年出现的一种面向多媒体计算机的音频总线，该总线专责于音频设备之间的数据传输，为数字立体声提供一个序列连接至标准编码解码器。S3C2410的IIS总线接口可以用实现对外部8/16位立体声音频数字信号编码解码电路的接口功能。它支持IIS总线数据格式和MSB-justified数据格式。IIS总线接口为FIFO操作提供DMA传输模式，代替中断模式，它可以同时传送或接收数据。Mode1程序：staticvoidInit1341(charmode){//PortInitialize////PORTBGROUP//Ports:GPB4GPB3GPB2//Signal:L3CLOCKL3DATAL3MODE//Setting:OUTPUTOUTPUTOUTPUT//[9:8][7:6}[5:4]//Binary:01,0101//rGPBDAT=rGPBDAT&~(L3M|L3C|L3D)|(L3M|L3C);//启动条件L3M=H,L3C=HrGPBUP=rGPBUP&~(0x7<<2)|(0x7<<2);//禁止上拉电阻GPB[4:2]rGPBCON=rGPBCON&~(0x3f<<4)|(0x15<<4);//GPB[4:2]=Output(L3CLOCK):Output(L3DATA):Output(L3MODE) //L3Interface_WrL3Addr(0x14+2); //地址设置(000101xx+10)_WrL3Data(0x60,0); //数据输入0,1,10,000,0_WrL3Addr(0x14+2); //STATUS(000101xx+10)FsIdx=mode?RecStatus.FsIdx:PlayStatus.FsIdx;if(CodecPara[FsIdx].ofs)_WrL3Data(0x18,0);else _WrL3Data(0x28,0); _WrL3Addr(0x14+2); //STATUS(000101xx+10)_WrL3Data(0xc1,0); //1,0,0,0,0,0,01 //DAC增益控制为6dB,ADC增益为dB。 //Recordif(mode){ //mode为1时选择录音状态 _WrL3Addr(0x14+2); //STATUS(000101xx+10)// _WrL3Data(0xa2,0); //1,0,1,0,0,0,10 //状态1，DAC增益为0dB,ADC增益为6dB。 _WrL3Data(0xe3,0);//状态1，DAC增益为6dB,ADC增益为0dB。打开使//录音时可从耳机听到声音// _WrL3Addr(0x14+0); //DATA0(000101xx+00)// _WrL3Data(0x3f,0); //00,111111Volumecontrol(6bits)// _WrL3Data(0x00,0); //00,000000Volumecontrol(6bits)0dB _WrL3Addr(0x14+0); //DATA0(000101xx+00) _WrL3Data(0x7b,0); //01,1110,11:Data0,BassBoost18~24dB,Treble6dB // _WrL3Addr(0x14+0); //DATA0(000101xx+00) _WrL3Data(0xc4,0); //11000,100:Extendedaddr(3bits),100// _WrL3Data(0x90,0); //100,100,00:DATA0,EnableAGC,00,inputamplifiergainchannel2(2bits) _WrL3Data(0xf0,0); //111,100,00:DATA0,EnableAGC,00,inputamplifiergainchannel2(2bits)// _WrL3Addr(0x14+0); //DATA0(000101xx+00) _WrL3Data(0xc0,0); //11000,000:Extendedaddr(3bits),000 _WrL3Data(0xe4,0); //111,00000:MA=0dB _WrL3Data(0xc1,0); //11000,001:Extendedaddr(3bits),001 _WrL3Data(0xe4,0); //111,00000:MB=0dB// _WrL3Addr(0x14+0); //DATA0(000101xx+00) _WrL3Data(0xc2,0); //11000,010:Extendedaddr(3bits),010// _WrL3Data(0x59,0); //010,110,01:DATA0,MICAmplifierGain27dB,inputchannel1select(inputchannel2off) _WrL3Data(0xf9,0); //111,110,11:DATA0,MICAmplifierGain27dB,input1XMA+input2XMB}}3.4录音模块程序：voidRecordTest(void){ intsize,i,j,err; WAVEFORMATEXfmt; WAVEHDRhdr[2048]; HWAVEINhwi=1; fmt.nSamplesPerSec=fsTable[3]; fmt.wBitsPerSample=16; fmt.wFormatTag =WAVE_FORMAT_PCM; fmt.nChannels =2; fmt.nBlockAlign=fmt.wBitsPerSample*fmt.nChannels/8; fmt.nAvgBytesPerSec =fmt.nSamplesPerSec*fmt.nBlockAlign; download_addr=0x30800000;//_NONCACHE_STARTADDRESS; download_len=size=2*1024*1024; for(i=0;i<download_len;i+=4)*(U32*)(download_addr+i)=0; i=0; while(size>0) { hdr[i].lpData=(LPSTR)(download_addr+0x2c+i*BUF_SIZE); hdr[i].dwBufferLength=(size>BUF_SIZE)?BUF_SIZE:size; size-=BUF_SIZE; i++; } *(U16*)(download_addr+0x14)=fmt.wFormatTag; *(U16*)(download_addr+0x16)=fmt.nChannels; *(U32*)(download_addr+0x18)=fmt.nSamplesPerSec; *(U32*)(download_addr+0x1c)=fmt.nAvgBytesPerSec; *(U16*)(download_addr+0x20)=fmt.nBlockAlign; *(U16*)(download_addr+0x22)=fmt.wBitsPerSample; *(U32*)(download_addr+0x28)=download_len; err=waveInOpen(&hwi, 0, &fmt, 0, 0, 0); printf("\nerr=%x\n",err); for(j=0;j<i;j++) if(waveInAddBuffer(hwi,&hdr[j],0)) puts("Addbuffererror!"); printf("Added%dbufferforrecord\n",i); //puts("PressanytoRecord\n"); //getch(); puts("Nowbeginrecording,PressEsctoexit\n"); waveInStart(hwi); while(1) { U8key; key=getkey(); if(key==ESC_KEY) break; } waveInClose(hwi); REC_OK=0xff; PlayMusicTest(); REC_OK=0;}3.5放音模块程序：voidPlayMusicTest(void){ intsize,i,j,err; WAVEFORMATEXfmt; WAVEHDRhdr[2048]; HWAVEOUThwo; U8pause=0; U8mute=0; U32volume; unsignedchar*buf; if(REC_OK==0) { download_addr=DFT_DOWNLOAD_ADDR; buf=(unsignedchar*)download_addr; for(i=0;i<243552;i++)buf[i]=WindowsXP_Wav[i]; download_len=243552; } size=*(U32*)(download_addr+0x28); i=0; while(size>0) { hdr[i].lpData=(LPSTR)(download_addr+0x2c+i*BUF_SIZE); hdr[i].dwBufferLength=(size>BUF_SIZE)?BUF_SIZE:size; size-=BUF_SIZE; i++; } fmt.wFormatTag =WAVE_FORMAT_PCM; fmt.nChannels =*(U16*)(download_addr+0x16); fmt.nSamplesPerSec =*(U32*)(download_addr+0x18); fmt.nAvgBytesPerSec =*(U32*)(download_addr+0x1c); fmt.nBlockAlign =*(U16*)(download_addr+0x20); fmt.wBitsPerSample =*(U16*)(download_addr+0x22); printf("SampleRate=%d,Channels=%d,%dBitsPerSample,size=%d\n", fmt.nSamplesPerSec,fmt.nChannels,fmt.wBitsPerSample,*(U32*)(download_addr+0x28)); hwo=0; err=waveOutOpen(&hwo, 0, &fmt, 0, 0, 0); printf("\nerr=%x\n",err); for(j=0;j<i;j++) waveOutWrite(0, &hdr[j],0); puts("Nowplayingthefile\n"); puts("PressEsctoexit,'+'toincvolume,'-'todecvolume,'y'tomute,Enterto'pause'\n"); waveOutGetVolume(0, &volume); while(1) { U8key=getch(); if(key==ESC_KEY) break; if(key==ENTER_KEY) { pause^=1; if(pause&1) waveOutPause(0); else waveOutRestart(0); } if(key=='y'||key=='Y') { mut