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Demo of Embedded Artists LPCXpresso baseboard SD card reader and audio facilities. Updated to put wav file player in a separate library and use the high capacity SD card library provided by Klaus Bu.
wavplayer.cpp
- Committer:
- tom_coxon
- Date:
- 2010-07-25
- Revision:
- 2:affcc36a50b4
File content as of revision 2:affcc36a50b4:
/* Library wave file player by Tom Coxon Based on WAVEplayer by Vlad Cazan/Stephan Rochon modified by Tom Coxon to: 1. Run correctly on the Embedded Artists LPCXpresso baseboard. 2. To play 8 bit sample size in addition to original 16 bit 3. To be more fault tolerant when playing wav files. */ #include "wavplayer.h" Ticker tick; AnalogOut DACout(p18); void WavPlayer::dac_out() { if (DAC_on) { DACout.write_u16(DAC_fifo[DAC_rptr]); DAC_rptr=(DAC_rptr+1) & 0xff; } } //void play_wave(char *wavname) { void WavPlayer::play_wave(char *wavname) { unsigned chunk_id,chunk_size,channel; unsigned data,samp_int,i; short dac_data; char *slice_buf; short *data_sptr; FMT_STRUCT wav_format; FILE *wavfile; long slice,num_slices; DAC_wptr=0; DAC_rptr=0; size_t result; for (i=0;i<256;i+=2) { DAC_fifo[i]=0; DAC_fifo[i+1]=3000; } DAC_wptr=4; DAC_on=0; printf("Playing wave file '%s'\r\n",wavname); wavfile=fopen(wavname,"rb"); if (!wavfile) { printf("Unable to open wav file '%s'\r\n",wavname); exit(1); } fread(&chunk_id,4,1,wavfile); fread(&chunk_size,4,1,wavfile); while (!feof(wavfile)) { printf("Read chunk ID 0x%x, size 0x%x\r\n",chunk_id,chunk_size); switch (chunk_id) { case 0x46464952: fread(&data,4,1,wavfile); printf("RIFF chunk\r\n"); printf(" chunk size %d (0x%x)\r\n",chunk_size,chunk_size); printf(" RIFF type 0x%x\r\n",data); break; case 0x20746d66: fread(&wav_format,sizeof(wav_format),1,wavfile); printf("FORMAT chunk\r\n"); printf(" chunk size %d (0x%x)\r\n",chunk_size,chunk_size); printf(" compression code %d\r\n",wav_format.comp_code); printf(" %d channels\r\n",wav_format.num_channels); printf(" %d samples/sec\r\n",wav_format.sample_rate); printf(" %d bytes/sec\r\n",wav_format.avg_Bps); printf(" block align %d\r\n",wav_format.block_align); printf(" %d bits per sample\r\n",wav_format.sig_bps); if (chunk_size > sizeof(wav_format)) fseek(wavfile,chunk_size-sizeof(wav_format),SEEK_CUR); // create a slice buffer large enough to hold multiple slices slice_buf=(char *)malloc(wav_format.block_align*SLICE_BUF_SIZE); if (!slice_buf) { printf("Unable to malloc slice buffer"); exit(1); } break; case 0x61746164: slice_buf=(char *)malloc(wav_format.block_align*SLICE_BUF_SIZE); if (!slice_buf) { printf("Unable to malloc slice buffer"); exit(1); } num_slices=chunk_size/wav_format.block_align; printf("DATA chunk\r\n"); printf(" chunk size %d (0x%x)\r\n",chunk_size,chunk_size); printf(" %d slices\r\n",num_slices); printf(" Ideal sample interval=%d\r\n",(unsigned)(1000000.0/wav_format.sample_rate)); samp_int=1000000/(wav_format.sample_rate); printf(" programmed interrupt tick interval=%d\r\n",samp_int); // starting up ticker to write samples out -- no printfs until tick.detach is called tick.attach_us(this,&WavPlayer::dac_out, samp_int); DAC_on=1; for (slice=0;slice<num_slices;slice+=SLICE_BUF_SIZE) { result = fread(slice_buf,wav_format.block_align*SLICE_BUF_SIZE,1,wavfile); if (feof(wavfile)) { printf("Oops -- not enough slices in the wave file\r\n"); break; } data_sptr=(short *)slice_buf; for (i=0;i<SLICE_BUF_SIZE;i++) { dac_data=0; // for a stereo wave file average the two channels. for (channel=0;channel<wav_format.num_channels;channel++) { switch (wav_format.sig_bps) { case 16: dac_data+=( ((int)(*data_sptr++)) +32768 ); break; case 8: dac_data+=( ((int)(*data_sptr++)) +32768 <<8); break; } } DAC_fifo[DAC_wptr]=dac_data; DAC_wptr=(DAC_wptr+1) & 0xff; while (DAC_wptr==DAC_rptr) { wait_us(10); } } } DAC_on=0; tick.detach(); printf("Ticker detached\r\n"); free(slice_buf); break; case 0x5453494c: printf("INFO chunk, size %d\r\n",chunk_size); fseek(wavfile,chunk_size,SEEK_CUR); break; default: printf("unknown chunk type 0x%x, size %d\r\n",chunk_id,chunk_size); data=fseek(wavfile,chunk_size,SEEK_CUR); break; } fread(&chunk_id,4,1,wavfile); fread(&chunk_size,4,1,wavfile); } printf("++++++++++++ Done with wave file ++++++++++\r\n"); fclose(wavfile); }