Stephane ROCHON
/
WAVEplayer
main.cpp
- Committer:
- Kerpower
- Date:
- 2010-01-02
- Revision:
- 0:4cda52c0c66e
File content as of revision 0:4cda52c0c66e:
#include "mbed.h" #include "SDFileSystem.h" AnalogOut DACout(p18); DigitalOut led1(LED1); DigitalOut led2(LED2); DigitalOut led3(LED3); DigitalOut led4(p8); DigitalOut digout(LED4); Ticker tick; SDFileSystem sd(p11, p12, p13, p14, "sd"); #define SAMPLE_FREQ 40000 #define BUF_SIZE (SAMPLE_FREQ/10) #define SLICE_BUF_SIZE 1 void dac_out(void); void play_wave(char *); void cleanup(char *); void fill_adc_buf(short *, unsigned); void swapword(unsigned *); // a FIFO for the DAC short DAC_fifo[256]; short DAC_wptr; short DAC_rptr; short DAC_on; typedef struct uFMT_STRUCT { short comp_code; short num_channels; unsigned sample_rate; unsigned avg_Bps; short block_align; short sig_bps; } FMT_STRUCT; int main() { led1=0; wait(.5); led1=1; wait(.5); led1=0; printf("Hello, world!\n"); play_wave("/sd/baddonut.wav"); printf("Back from play_wave()\n"); play_wave("/sd/clint16.wav"); printf("Back from play_wave()\n"); printf("Goodbye, world!\n"); led1=1; wait(.5); led1=0; wait(.5); led1=1; } void play_wave(char *wavname) { unsigned chunk_id,chunk_size,channel; // unsigned *data_wptr,data,samp_int,i; unsigned data,samp_int,i; short dac_data; char *slice_buf; short *data_sptr; // char *data_bptr; FMT_STRUCT wav_format; FILE *wavfile; long slice,num_slices; DAC_wptr=0; DAC_rptr=0; for (i=0;i<256;i+=2) { DAC_fifo[i]=0; DAC_fifo[i+1]=3000; } DAC_wptr=4; DAC_on=0; led1=led2=led3=led4=0; printf("Playing wave file '%s'\n",wavname); wavfile=fopen(wavname,"rb"); if (!wavfile) { printf("Unable to open wav file '%s'\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\n",chunk_id,chunk_size); switch (chunk_id) { case 0x46464952: fread(&data,4,1,wavfile); printf("RIFF chunk\n"); printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size); printf(" RIFF type 0x%x\n",data); break; case 0x20746d66: fread(&wav_format,sizeof(wav_format),1,wavfile); printf("FORMAT chunk\n"); printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size); printf(" compression code %d\n",wav_format.comp_code); printf(" %d channels\n",wav_format.num_channels); printf(" %d samples/sec\n",wav_format.sample_rate); printf(" %d bytes/sec\n",wav_format.avg_Bps); printf(" block align %d\n",wav_format.block_align); printf(" %d bits per sample\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\n"); printf(" chunk size %d (0x%x)\n",chunk_size,chunk_size); printf(" %d slices\n",num_slices); printf(" Ideal sample interval=%d\n",(unsigned)(1000000.0/wav_format.sample_rate)); samp_int=1000000/(wav_format.sample_rate); printf(" programmed interrupt tick interval=%d\n",samp_int); // starting up ticker to write samples out -- no printfs until tick.detach is called tick.attach_us(&dac_out, samp_int); DAC_on=1; led2=1; for (slice=0;slice<num_slices;slice+=SLICE_BUF_SIZE) { fread(slice_buf,wav_format.block_align*SLICE_BUF_SIZE,1,wavfile); if (feof(wavfile)) { printf("Oops -- not enough slices in the wave file\n"); exit(1); } 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)>>5; break; } } dac_data>>=1; DAC_fifo[DAC_wptr]=dac_data; DAC_wptr=(DAC_wptr+1) & 0xff; while (DAC_wptr==DAC_rptr) { led1=1; } led1=0; } } DAC_on=0; led2=0; tick.detach(); printf("Ticker detached\n"); led3=1; free(slice_buf); break; case 0x5453494c: printf("INFO chunk, size %d\n",chunk_size); fseek(wavfile,chunk_size,SEEK_CUR); break; default: printf("unknown chunk type 0x%x, size %d\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\n"); fclose(wavfile); led1=0; } void dac_out() { if (DAC_on) { digout=1; DACout.write_u16(DAC_fifo[DAC_rptr]); DAC_rptr=(DAC_rptr+1) & 0xff; digout=0; } }