linkman marutsu / Mbed 2 deprecated Music_Player_for_MAPLE

Music Player for LPC1768 and MAPLE Board

Dependencies:   SDFileSystem mbed

wave_player_appbd/wave_player.cpp@0:b347ed8fee7f, 2014-02-03 (annotated)

Committer:
marutsu
Date:
Mon Feb 03 08:58:23 2014 +0000
Revision:
0:b347ed8fee7f
mbed(LPC1768),MAPLE???,MARY-UB????????????????MicroSD????Music?????wave????????????

Who changed what in which revision?

UserRevisionLine numberNew contents of line
marutsu 0:b347ed8fee7f 1 //-----------------------------------------------------------------------------
marutsu 0:b347ed8fee7f 2 // a sample mbed library to play back wave files.
marutsu 0:b347ed8fee7f 3 //
marutsu 0:b347ed8fee7f 4 // explanation of wave file format.
marutsu 0:b347ed8fee7f 5 // https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
marutsu 0:b347ed8fee7f 6
marutsu 0:b347ed8fee7f 7 // if VERBOSE is uncommented then the wave player will enter a verbose
marutsu 0:b347ed8fee7f 8 // mode that displays all data values as it reads them from the file
marutsu 0:b347ed8fee7f 9 // and writes them to the DAC. Very slow and unusable output on the DAC,
marutsu 0:b347ed8fee7f 10 // but useful for debugging wave files that don't work.
marutsu 0:b347ed8fee7f 11 //#define VERBOSE
marutsu 0:b347ed8fee7f 12
marutsu 0:b347ed8fee7f 13
marutsu 0:b347ed8fee7f 14 #include <mbed.h>
marutsu 0:b347ed8fee7f 15 #include <stdio.h>
marutsu 0:b347ed8fee7f 16 #include <wave_player.h>
marutsu 0:b347ed8fee7f 17
marutsu 0:b347ed8fee7f 18
marutsu 0:b347ed8fee7f 19 //-----------------------------------------------------------------------------
marutsu 0:b347ed8fee7f 20 // constructor -- accepts an mbed pin to use for AnalogOut. Only p18 will work
marutsu 0:b347ed8fee7f 21 wave_player::wave_player(AnalogOut *_dac, PwmOut *_pwm)
marutsu 0:b347ed8fee7f 22 {
marutsu 0:b347ed8fee7f 23
marutsu 0:b347ed8fee7f 24
marutsu 0:b347ed8fee7f 25 wave_PWM= _pwm;
marutsu 0:b347ed8fee7f 26 wave_DAC=_dac;
marutsu 0:b347ed8fee7f 27 wave_DAC->write_u16(32768); //DAC is 0-3.3V, so idles at ~1.6V
marutsu 0:b347ed8fee7f 28 *wave_PWM=32768;
marutsu 0:b347ed8fee7f 29 verbosity=0;
marutsu 0:b347ed8fee7f 30 }
marutsu 0:b347ed8fee7f 31
marutsu 0:b347ed8fee7f 32 //-----------------------------------------------------------------------------
marutsu 0:b347ed8fee7f 33 // if verbosity is set then wave player enters a mode where the wave file
marutsu 0:b347ed8fee7f 34 // is decoded and displayed to the screen, including sample values put into
marutsu 0:b347ed8fee7f 35 // the DAC FIFO, and values read out of the DAC FIFO by the ISR. The DAC output
marutsu 0:b347ed8fee7f 36 // itself is so slow as to be unusable, but this might be handy for debugging
marutsu 0:b347ed8fee7f 37 // wave files that don't play
marutsu 0:b347ed8fee7f 38 //-----------------------------------------------------------------------------
marutsu 0:b347ed8fee7f 39 void wave_player::set_verbosity(int v)
marutsu 0:b347ed8fee7f 40 {
marutsu 0:b347ed8fee7f 41 verbosity=v;
marutsu 0:b347ed8fee7f 42 }
marutsu 0:b347ed8fee7f 43
marutsu 0:b347ed8fee7f 44 //-----------------------------------------------------------------------------
marutsu 0:b347ed8fee7f 45 // player function. Takes a pointer to an opened wave file. The file needs
marutsu 0:b347ed8fee7f 46 // to be stored in a filesystem with enough bandwidth to feed the wave data.
marutsu 0:b347ed8fee7f 47 // LocalFileSystem isn't, but the SDcard is, at least for 22kHz files. The
marutsu 0:b347ed8fee7f 48 // SDcard filesystem can be hotrodded by increasing the SPI frequency it uses
marutsu 0:b347ed8fee7f 49 // internally.
marutsu 0:b347ed8fee7f 50 //-----------------------------------------------------------------------------
marutsu 0:b347ed8fee7f 51 void wave_player::play(FILE *wavefile)
marutsu 0:b347ed8fee7f 52 {
marutsu 0:b347ed8fee7f 53 unsigned chunk_id,chunk_size,channel;
marutsu 0:b347ed8fee7f 54 unsigned data,samp_int,i;
marutsu 0:b347ed8fee7f 55 short unsigned dac_data;
marutsu 0:b347ed8fee7f 56 long long slice_value;
marutsu 0:b347ed8fee7f 57 char *slice_buf;
marutsu 0:b347ed8fee7f 58 short *data_sptr;
marutsu 0:b347ed8fee7f 59 unsigned char *data_bptr;
marutsu 0:b347ed8fee7f 60 int *data_wptr;
marutsu 0:b347ed8fee7f 61 FMT_STRUCT wav_format;
marutsu 0:b347ed8fee7f 62 long slice,num_slices;
marutsu 0:b347ed8fee7f 63 DAC_wptr=0;
marutsu 0:b347ed8fee7f 64 DAC_rptr=0;
marutsu 0:b347ed8fee7f 65 for (i=0;i<256;i+=2) {
marutsu 0:b347ed8fee7f 66 DAC_fifo[i]=0;
marutsu 0:b347ed8fee7f 67 DAC_fifo[i+1]=3000;
marutsu 0:b347ed8fee7f 68 }
marutsu 0:b347ed8fee7f 69 DAC_wptr=4;
marutsu 0:b347ed8fee7f 70 DAC_on=0;
marutsu 0:b347ed8fee7f 71
marutsu 0:b347ed8fee7f 72 fread(&chunk_id,4,1,wavefile);
marutsu 0:b347ed8fee7f 73 fread(&chunk_size,4,1,wavefile);
marutsu 0:b347ed8fee7f 74 while (!feof(wavefile)) {
marutsu 0:b347ed8fee7f 75 if (verbosity)
marutsu 0:b347ed8fee7f 76 printf("Read chunk ID 0x%x, size 0x%x\n",chunk_id,chunk_size);
marutsu 0:b347ed8fee7f 77 switch (chunk_id) {
marutsu 0:b347ed8fee7f 78 case 0x46464952:
marutsu 0:b347ed8fee7f 79 fread(&data,4,1,wavefile);
marutsu 0:b347ed8fee7f 80 if (verbosity) {
marutsu 0:b347ed8fee7f 81 printf("RIFF chunk\n");
marutsu 0:b347ed8fee7f 82 printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size);
marutsu 0:b347ed8fee7f 83 printf(" RIFF type 0x%x\n",data);
marutsu 0:b347ed8fee7f 84 }
marutsu 0:b347ed8fee7f 85 break;
marutsu 0:b347ed8fee7f 86 case 0x20746d66:
marutsu 0:b347ed8fee7f 87 fread(&wav_format,sizeof(wav_format),1,wavefile);
marutsu 0:b347ed8fee7f 88 if (verbosity) {
marutsu 0:b347ed8fee7f 89 printf("FORMAT chunk\n");
marutsu 0:b347ed8fee7f 90 printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size);
marutsu 0:b347ed8fee7f 91 printf(" compression code %d\n",wav_format.comp_code);
marutsu 0:b347ed8fee7f 92 printf(" %d channels\n",wav_format.num_channels);
marutsu 0:b347ed8fee7f 93 printf(" %d samples/sec\n",wav_format.sample_rate);
marutsu 0:b347ed8fee7f 94 printf(" %d bytes/sec\n",wav_format.avg_Bps);
marutsu 0:b347ed8fee7f 95 printf(" block align %d\n",wav_format.block_align);
marutsu 0:b347ed8fee7f 96 printf(" %d bits per sample\n",wav_format.sig_bps);
marutsu 0:b347ed8fee7f 97 }
marutsu 0:b347ed8fee7f 98 if (chunk_size > sizeof(wav_format))
marutsu 0:b347ed8fee7f 99 fseek(wavefile,chunk_size-sizeof(wav_format),SEEK_CUR);
marutsu 0:b347ed8fee7f 100 break;
marutsu 0:b347ed8fee7f 101 case 0x61746164:
marutsu 0:b347ed8fee7f 102 // allocate a buffer big enough to hold a slice
marutsu 0:b347ed8fee7f 103 slice_buf=(char *)malloc(wav_format.block_align);
marutsu 0:b347ed8fee7f 104 if (!slice_buf) {
marutsu 0:b347ed8fee7f 105 printf("Unable to malloc slice buffer");
marutsu 0:b347ed8fee7f 106 exit(1);
marutsu 0:b347ed8fee7f 107 }
marutsu 0:b347ed8fee7f 108 num_slices=chunk_size/wav_format.block_align;
marutsu 0:b347ed8fee7f 109 samp_int=1000000/(wav_format.sample_rate);
marutsu 0:b347ed8fee7f 110 if (verbosity) {
marutsu 0:b347ed8fee7f 111 printf("DATA chunk\n");
marutsu 0:b347ed8fee7f 112 printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size);
marutsu 0:b347ed8fee7f 113 printf(" %d slices\n",num_slices);
marutsu 0:b347ed8fee7f 114 printf(" Ideal sample interval=%d\n",(unsigned)(1000000.0/wav_format.sample_rate));
marutsu 0:b347ed8fee7f 115 printf(" programmed interrupt tick interval=%d\n",samp_int);
marutsu 0:b347ed8fee7f 116 }
marutsu 0:b347ed8fee7f 117
marutsu 0:b347ed8fee7f 118 // starting up ticker to write samples out -- no printfs until tick.detach is called
marutsu 0:b347ed8fee7f 119 if (verbosity)
marutsu 0:b347ed8fee7f 120 tick.attach_us(this,&wave_player::dac_out, 500000);
marutsu 0:b347ed8fee7f 121 else
marutsu 0:b347ed8fee7f 122 tick.attach_us(this,&wave_player::dac_out, samp_int);
marutsu 0:b347ed8fee7f 123 DAC_on=1;
marutsu 0:b347ed8fee7f 124
marutsu 0:b347ed8fee7f 125 // start reading slices, which contain one sample each for however many channels
marutsu 0:b347ed8fee7f 126 // are in the wave file. one channel=mono, two channels=stereo, etc. Since
marutsu 0:b347ed8fee7f 127 // mbed only has a single AnalogOut, all of the channels present are averaged
marutsu 0:b347ed8fee7f 128 // to produce a single sample value. This summing and averaging happens in
marutsu 0:b347ed8fee7f 129 // a variable of type signed long long, to make sure that the data doesn't
marutsu 0:b347ed8fee7f 130 // overflow regardless of sample size (8 bits, 16 bits, 32 bits).
marutsu 0:b347ed8fee7f 131 //
marutsu 0:b347ed8fee7f 132 // note that from what I can find that 8 bit wave files use unsigned data,
marutsu 0:b347ed8fee7f 133 // while 16 and 32 bit wave files use signed data
marutsu 0:b347ed8fee7f 134 //
marutsu 0:b347ed8fee7f 135 for (slice=0;slice<num_slices;slice+=1) {
marutsu 0:b347ed8fee7f 136 fread(slice_buf,wav_format.block_align,1,wavefile);
marutsu 0:b347ed8fee7f 137 if (feof(wavefile)) {
marutsu 0:b347ed8fee7f 138 printf("Oops -- not enough slices in the wave file\n");
marutsu 0:b347ed8fee7f 139 exit(1);
marutsu 0:b347ed8fee7f 140 }
marutsu 0:b347ed8fee7f 141 data_sptr=(short *)slice_buf; // 16 bit samples
marutsu 0:b347ed8fee7f 142 data_bptr=(unsigned char *)slice_buf; // 8 bit samples
marutsu 0:b347ed8fee7f 143 data_wptr=(int *)slice_buf; // 32 bit samples
marutsu 0:b347ed8fee7f 144 slice_value=0;
marutsu 0:b347ed8fee7f 145 for (channel=0;channel<wav_format.num_channels;channel++) {
marutsu 0:b347ed8fee7f 146 switch (wav_format.sig_bps) {
marutsu 0:b347ed8fee7f 147 case 16:
marutsu 0:b347ed8fee7f 148 if (verbosity)
marutsu 0:b347ed8fee7f 149 printf("16 bit channel %d data=%d ",channel,data_sptr[channel]);
marutsu 0:b347ed8fee7f 150 slice_value+=data_sptr[channel];
marutsu 0:b347ed8fee7f 151 break;
marutsu 0:b347ed8fee7f 152 case 32:
marutsu 0:b347ed8fee7f 153 if (verbosity)
marutsu 0:b347ed8fee7f 154 printf("32 bit channel %d data=%d ",channel,data_wptr[channel]);
marutsu 0:b347ed8fee7f 155 slice_value+=data_wptr[channel];
marutsu 0:b347ed8fee7f 156 break;
marutsu 0:b347ed8fee7f 157 case 8:
marutsu 0:b347ed8fee7f 158 if (verbosity)
marutsu 0:b347ed8fee7f 159 printf("8 bit channel %d data=%d ",channel,(int)data_bptr[channel]);
marutsu 0:b347ed8fee7f 160 slice_value+=data_bptr[channel];
marutsu 0:b347ed8fee7f 161 break;
marutsu 0:b347ed8fee7f 162 }
marutsu 0:b347ed8fee7f 163 }
marutsu 0:b347ed8fee7f 164 slice_value/=wav_format.num_channels;
marutsu 0:b347ed8fee7f 165
marutsu 0:b347ed8fee7f 166 // slice_value is now averaged. Next it needs to be scaled to an unsigned 16 bit value
marutsu 0:b347ed8fee7f 167 // with DC offset so it can be written to the DAC.
marutsu 0:b347ed8fee7f 168 switch (wav_format.sig_bps) {
marutsu 0:b347ed8fee7f 169 case 8: slice_value<<=8;
marutsu 0:b347ed8fee7f 170 break;
marutsu 0:b347ed8fee7f 171 case 16: slice_value+=32768;
marutsu 0:b347ed8fee7f 172 break;
marutsu 0:b347ed8fee7f 173 case 32: slice_value>>=16;
marutsu 0:b347ed8fee7f 174 slice_value+=32768;
marutsu 0:b347ed8fee7f 175 break;
marutsu 0:b347ed8fee7f 176 }
marutsu 0:b347ed8fee7f 177 dac_data=(short unsigned)slice_value;
marutsu 0:b347ed8fee7f 178 if (verbosity)
marutsu 0:b347ed8fee7f 179 printf("sample %d wptr %d slice_value %d dac_data %u\n",slice,DAC_wptr,(int)slice_value,dac_data);
marutsu 0:b347ed8fee7f 180 DAC_fifo[DAC_wptr]=dac_data;
marutsu 0:b347ed8fee7f 181 DAC_wptr=(DAC_wptr+1) & 0xff;
marutsu 0:b347ed8fee7f 182 while (DAC_wptr==DAC_rptr) {
marutsu 0:b347ed8fee7f 183 }
marutsu 0:b347ed8fee7f 184 }
marutsu 0:b347ed8fee7f 185 DAC_on=0;
marutsu 0:b347ed8fee7f 186 tick.detach();
marutsu 0:b347ed8fee7f 187 free(slice_buf);
marutsu 0:b347ed8fee7f 188 break;
marutsu 0:b347ed8fee7f 189 case 0x5453494c:
marutsu 0:b347ed8fee7f 190 if (verbosity)
marutsu 0:b347ed8fee7f 191 printf("INFO chunk, size %d\n",chunk_size);
marutsu 0:b347ed8fee7f 192 fseek(wavefile,chunk_size,SEEK_CUR);
marutsu 0:b347ed8fee7f 193 break;
marutsu 0:b347ed8fee7f 194 default:
marutsu 0:b347ed8fee7f 195 printf("unknown chunk type 0x%x, size %d\n",chunk_id,chunk_size);
marutsu 0:b347ed8fee7f 196 data=fseek(wavefile,chunk_size,SEEK_CUR);
marutsu 0:b347ed8fee7f 197 break;
marutsu 0:b347ed8fee7f 198 }
marutsu 0:b347ed8fee7f 199 fread(&chunk_id,4,1,wavefile);
marutsu 0:b347ed8fee7f 200 fread(&chunk_size,4,1,wavefile);
marutsu 0:b347ed8fee7f 201 }
marutsu 0:b347ed8fee7f 202 }
marutsu 0:b347ed8fee7f 203
marutsu 0:b347ed8fee7f 204
marutsu 0:b347ed8fee7f 205 void wave_player::dac_out()
marutsu 0:b347ed8fee7f 206 {
marutsu 0:b347ed8fee7f 207 if (DAC_on) {
marutsu 0:b347ed8fee7f 208 #ifdef VERBOSE
marutsu 0:b347ed8fee7f 209 printf("ISR rdptr %d got %u\n",DAC_rptr,DAC_fifo[DAC_rptr]);
marutsu 0:b347ed8fee7f 210 #endif
marutsu 0:b347ed8fee7f 211 //scale down Analog voltage by 8 for PC speakers
marutsu 0:b347ed8fee7f 212 wave_DAC->write_u16(DAC_fifo[DAC_rptr]>>3);
marutsu 0:b347ed8fee7f 213 //Output to onboard speaker using PWM (Class D Audio Amp!)
marutsu 0:b347ed8fee7f 214 wave_PWM->write(float(DAC_fifo[DAC_rptr]/65536.0));
marutsu 0:b347ed8fee7f 215 DAC_rptr=(DAC_rptr+1) & 0xff;
marutsu 0:b347ed8fee7f 216 }
marutsu 0:b347ed8fee7f 217 }
marutsu 0:b347ed8fee7f 218