wave_player.cpp

00001 //-----------------------------------------------------------------------------
00002 // a sample mbed library to play back wave files using MODDMA 
00003 // Based on the wave_player library by Steve Ravet and the 
00004 // MODDMA library by Andy Kirkham. 
00005 // 
00006 // The wave_player library is located here:
00007 // https://developer.mbed.org/users/sravet/code/wave_player/
00008 // 
00009 // The MODDMA library is located here:
00010 // https://developer.mbed.org/users/AjK/code/MODDMA/
00011 // A wiki page and example are located here:
00012 // https://developer.mbed.org/cookbook/MODDMA
00013 //
00014 // explanation of wave file format.
00015 // https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
00016 
00017 // if VERBOSE is uncommented then the wave player will enter a verbose
00018 // mode that displays all data values as it reads them from the file
00019 // and writes them to the DAC.  Very slow and unusable output on the DAC,
00020 // but useful for debugging wave files that don't work.
00021 //#define VERBOSE
00022 
00023 
00024 #include <mbed.h>
00025 #include <stdio.h>
00026 #include <wave_player.h>
00027 
00028 //-----------------------------------------------------------------------------
00029 // constructor -- accepts an mbed pin to use for AnalogOut.  Only p18 will work
00030 wave_player::wave_player(AnalogOut *_dac)
00031 {
00032   wave_DAC=_dac;
00033   wave_DAC->write_u16(32768);        //DAC is 0-3.3V, so idles at ~1.6V
00034   verbosity=0;
00035 }
00036 
00037 //-----------------------------------------------------------------------------
00038 // if verbosity is set then wave player enters a mode where the wave file
00039 // is decoded and displayed to the screen, including sample values put into
00040 // the DAC FIFO, and values read out of the DAC FIFO by the ISR.  The DAC output
00041 // itself is so slow as to be unusable, but this might be handy for debugging
00042 // wave files that don't play
00043 //-----------------------------------------------------------------------------
00044 void wave_player::set_verbosity(int v)
00045 {
00046   verbosity=v;
00047 }
00048 
00049 //-----------------------------------------------------------------------------
00050 // player function.  Takes a pointer to an opened wave file.  The file needs
00051 // to be stored in a filesystem with enough bandwidth to feed the wave data.
00052 // LocalFileSystem isn't, but the SDcard is, at least for 22kHz files.  The
00053 // SDcard filesystem can be hotrodded by increasing the SPI frequency it uses
00054 // internally.
00055 //-----------------------------------------------------------------------------
00056 void wave_player::play(FILE *wavefile)
00057 {
00058     unsigned chunk_id,chunk_size,channel;
00059     unsigned data,i;
00060     unsigned j,k;
00061     int dac_cntval;
00062     bool buf0_flag;
00063     long long slice_value;
00064     char *slice_buf;
00065     short *data_sptr;
00066     unsigned char *data_bptr;
00067     int *data_wptr;
00068     FMT_STRUCT wav_format;
00069     long num_slices;
00070   
00071     for(i=0; i<BUF_SIZE; i++){
00072         DAC_buf0[i]=0;
00073         DAC_buf1[i]=0;
00074     }   
00075   
00076     DAC_on=0;
00077   
00078     int time=0;
00079 
00080     fread(&chunk_id,4,1,wavefile);
00081     fread(&chunk_size,4,1,wavefile);
00082   
00083     while (!feof(wavefile)) {
00084         if (verbosity)
00085             printf("Read chunk ID 0x%x, size 0x%x\n",chunk_id,chunk_size);
00086         switch (chunk_id) {
00087             case 0x46464952:
00088                 fread(&data,4,1,wavefile);
00089                 if (verbosity) {
00090                     printf("RIFF chunk\n");
00091                     printf("  chunk size %d (0x%x)\n",chunk_size,chunk_size);
00092                     printf("  RIFF type 0x%x\n",data);
00093                 }
00094                 break;
00095             case 0x20746d66:
00096                 fread(&wav_format,sizeof(wav_format),1,wavefile);
00097                 if (verbosity) {
00098                     printf("FORMAT chunk\n");
00099                     printf("  chunk size %d (0x%x)\n",chunk_size,chunk_size);
00100                     printf("  compression code %d\n",wav_format.comp_code);
00101                     printf("  %d channels\n",wav_format.num_channels);
00102                     printf("  %d samples/sec\n",wav_format.sample_rate);
00103                     printf("  %d bytes/sec\n",wav_format.avg_Bps);
00104                     printf("  block align %d\n",wav_format.block_align);
00105                     printf("  %d bits per sample\n",wav_format.sig_bps);
00106                 }
00107                 if (chunk_size > sizeof(wav_format))
00108                     fseek(wavefile,chunk_size-sizeof(wav_format),SEEK_CUR);
00109                 break;
00110             case 0x61746164:
00111                 // Data chunk which contains the audio samples to send to the DAC
00112             
00113                 // allocate a buffer big enough to hold a slice
00114                 slice_buf=(char *)malloc(wav_format.block_align);
00115                 if (!slice_buf) {
00116                     printf("Unable to malloc slice buffer");
00117                     exit(1);
00118                 }
00119                 num_slices=chunk_size/wav_format.block_align;
00120         
00121                 // Calculating the transfer frequency:
00122                 // By default, the Mbed library sets the PCLK_DAC clock value
00123                 // to 24MHz. 
00124         
00125                 dac_cntval=(24000000/wav_format.sample_rate);
00126        
00127                 if (verbosity) {
00128                     printf("DATA chunk\n\r");
00129                     printf("  chunk size %d (0x%x)\n\r",chunk_size,chunk_size);
00130                     printf("  %d slices\n\r",num_slices);
00131                     printf("  sample rate is %d\r\n", wav_format.sample_rate);
00132                     printf("  Ideal sample interval=%d\n\r",(unsigned)(1000000.0/wav_format.sample_rate));
00133                     printf("  programmed interrupt tick interval=%d\n\r",dac_cntval);
00134                 }
00135   
00136                 // Prepare the GPDMA system for buffer0.
00137                 conf0 = new MODDMA_Config;
00138                 conf0
00139                 ->channelNum    ( MODDMA::Channel_0 )
00140                 ->srcMemAddr    ( (uint32_t) &DAC_buf0 )
00141                 ->dstMemAddr    ( MODDMA::DAC )
00142                 ->transferSize  ( BUF_SIZE )
00143                 ->transferType  ( MODDMA::m2p )
00144                 ->dstConn       ( MODDMA::DAC )
00145                 ->attach_tc     ( this,&wave_player::TC0_callback )
00146                 ->attach_err    ( this,&wave_player::ERR0_callback )     
00147                 ; // config end
00148     
00149                 // Prepare the GPDMA system for buffer1.
00150                 conf1 = new MODDMA_Config;
00151                 conf1
00152                 ->channelNum    ( MODDMA::Channel_1 )
00153                 ->srcMemAddr    ( (uint32_t) &DAC_buf1 )
00154                 ->dstMemAddr    ( MODDMA::DAC )
00155                 ->transferSize  ( BUF_SIZE )
00156                 ->transferType  ( MODDMA::m2p )
00157                 ->dstConn       ( MODDMA::DAC )
00158                 ->attach_tc     ( this,&wave_player::TC1_callback )
00159                 ->attach_err    ( this,&wave_player::ERR1_callback )     
00160                 ; // config end
00161     
00162                 // Set the DAC to the audio sample rate
00163                 LPC_DAC->DACCNTVAL = dac_cntval;
00164     
00165                 // Begin (enable DMA and counter). Note, don't enable
00166                 // DBLBUF_ENA as we are using DMA double buffering.
00167                 LPC_DAC->DACCTRL |= (3UL << 2);
00168   
00169                 DAC_on=1; 
00170 
00171                 // start reading slices, which contain one sample each for however many channels
00172                 // are in the wave file.  one channel=mono, two channels=stereo, etc.  Since
00173                 // mbed only has a single AnalogOut, all of the channels present are averaged
00174                 // to produce a single sample value.  This summing and averaging happens in
00175                 // a variable of type signed long long, to make sure that the data doesn't
00176                 // overflow regardless of sample size (8 bits, 16 bits, 32 bits).
00177                 //
00178                 // note that from what I can find that 8 bit wave files use unsigned data,
00179                 // while 16 and 32 bit wave files use signed data
00180                 //
00181                 
00182                 // Fill buffer 0 first
00183                 buf0_flag=1;
00184         
00185                 // Separate slices into sections of BUF_SIZE samples        
00186                 for (j=0; j<((num_slices/BUF_SIZE)+1); j++)
00187                 {
00188                     for(k=0; k<BUF_SIZE; k++)
00189                     {
00190                         // The last buffer will likely not be exactly BUF_SIZE,
00191                         // so fill the remaining spots with 0
00192                         if((j*BUF_SIZE+k)>num_slices){
00193                             if(buf0_flag)
00194                                 DAC_buf0[k]=0;
00195                             else
00196                                 DAC_buf1[k]=0;
00197                         }
00198                         else{
00199                             // Read audio samples from sd card
00200                             fread(slice_buf,wav_format.block_align,1,wavefile);
00201                             if (feof(wavefile)) {
00202                                 printf("Oops -- not enough slices in the wave file\n");
00203                                 exit(1);
00204                             }
00205                             data_sptr=(short *)slice_buf;     // 16 bit samples
00206                             data_bptr=(unsigned char *)slice_buf;     // 8 bit samples
00207                             data_wptr=(int *)slice_buf;     // 32 bit samples
00208                             slice_value=0;
00209                             for (channel=0;channel<wav_format.num_channels;channel++) {
00210                                 switch (wav_format.sig_bps) {
00211                                     case 16:
00212                                         if (verbosity)
00213                                             printf("16 bit channel %d data=%d ",channel,data_sptr[channel]);
00214                                         slice_value+=data_sptr[channel];
00215                                         break;
00216                                     case 32:
00217                                         if (verbosity)
00218                                             printf("32 bit channel %d data=%d ",channel,data_wptr[channel]);
00219                                         slice_value+=data_wptr[channel];
00220                                         break;
00221                                     case 8:
00222                                         if (verbosity)
00223                                             printf("8 bit channel %d data=%d ",channel,(int)data_bptr[channel]);
00224                                         slice_value+=data_bptr[channel];
00225                                         break;
00226                                 }
00227                             }
00228                             slice_value/=wav_format.num_channels;
00229               
00230                             // slice_value is now averaged.  Next it needs to be scaled to an unsigned 16 bit value
00231                             // with DC offset so it can be written to the DAC.
00232                             switch (wav_format.sig_bps) {
00233                                 case 8:     slice_value<<=8;
00234                                     break;
00235                                 case 16:    slice_value+=32768;
00236                                     break;
00237                                 case 32:    slice_value>>=16;
00238                                             slice_value+=32768;
00239                                     break;
00240                             }
00241 
00242                             if (verbosity)
00243                                 printf("sample %d slice_value %d\n",(j*BUF_SIZE+k),(int)slice_value);
00244                             if(buf0_flag)
00245                                 DAC_buf0[k]=(uint32_t)slice_value;
00246                             else
00247                                 DAC_buf1[k]=(uint32_t)slice_value;
00248                         }
00249                     }
00250           
00251                     // Except for the first buffer, wait until the previous DMA transfer is
00252                     // complete before switching buffers
00253                     if(j>0)
00254                     {
00255                         while((dma0_fin_flag==0)&(dma1_fin_flag==0)&(time<500000000)){
00256                             wait_us(1);
00257                             time++;
00258                         }
00259                     }
00260                     
00261                     if (time>499999999)
00262                     {
00263                         printf("timeout, %d of %d\r\n", (j*BUF_SIZE), num_slices);
00264                         exit(1);
00265                     }
00266             
00267                     time=0;
00268                     dma0_fin_flag=0;
00269                     dma1_fin_flag=0; 
00270           
00271                     // If finished filling buffer 0, set flag to fill buffer 1
00272                     // and start the DMA transfer for buffer 0
00273                     if(buf0_flag==1)
00274                     {
00275                         buf0_flag=0;
00276                         dma.Setup(conf0);
00277                         dma.Enable( conf0 );
00278                     }
00279                     else // Similarly for buffer 1
00280                     {
00281                         buf0_flag=1;
00282                         dma.Setup(conf1);
00283                         dma.Enable( conf1 );
00284                     }
00285 
00286                 }
00287                 DAC_on=0;
00288                 delete conf0;
00289                 delete conf1;
00290                 free(slice_buf);
00291                 break;
00292             case 0x5453494c:
00293                 if (verbosity)
00294                     printf("INFO chunk, size %d\n",chunk_size);
00295                 fseek(wavefile,chunk_size,SEEK_CUR);
00296                 break;
00297             default:
00298                 printf("unknown chunk type 0x%x, size %d\n",chunk_id,chunk_size);
00299                 data=fseek(wavefile,chunk_size,SEEK_CUR);
00300                 break;
00301         }
00302         fread(&chunk_id,4,1,wavefile);
00303         fread(&chunk_size,4,1,wavefile);
00304     }
00305 }
00306 
00307 // Configuration callback on TC; runs when the DMA has finished transferring buffer 0 to the DAC
00308 void wave_player::TC0_callback(void) {
00309         
00310     // Get configuration pointer.
00311     MODDMA_Config *config = dma.getConfig();
00312     
00313     // Only run once
00314     dma.haltAndWaitChannelComplete( (MODDMA::CHANNELS)config->channelNum());
00315     
00316     // Finish the DMA cycle by shutting down the channel.
00317     dma.Disable( (MODDMA::CHANNELS)config->channelNum() );
00318 
00319     // Clear DMA IRQ flags.
00320     if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq();
00321     
00322     // Indicate that buffer 0 has finished transferring
00323     dma0_fin_flag=1; 
00324 }
00325 
00326 // Configuration callback on Error
00327 void wave_player::ERR0_callback(void) {
00328     error("Oh no! My Mbed EXPLODED! :( Only kidding, go find the problem");
00329 }
00330 
00331 // Configuration callback on TC; runs when the DMA has finished transferring buffer 1 to the DAC
00332 void wave_player::TC1_callback(void) {
00333         
00334     // Get configuration pointer.
00335     MODDMA_Config *config = dma.getConfig();
00336     
00337     // Only run once
00338     dma.haltAndWaitChannelComplete( (MODDMA::CHANNELS)config->channelNum());
00339     
00340     // Finish the DMA cycle by shutting down the channel.
00341     dma.Disable( (MODDMA::CHANNELS)config->channelNum() );
00342     
00343     // Clear DMA IRQ flags.
00344     if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq(); 
00345     
00346     // Indicate that buffer 1 has finished transferring
00347     dma1_fin_flag=1;
00348 }
00349 
00350 // Configuration callback on Error
00351 void wave_player::ERR1_callback(void) {
00352     error("Oh no! My Mbed EXPLODED! :( Only kidding, go find the problem");
00353 }