Edited version of the wave player class that uses the MODDMA library to handle transfers to the DAC.
Dependents: WavePlayer_MODDMA wave_player_DMA_mbed
wave_player.cpp
- Committer:
- ebradley6
- Date:
- 2016-03-16
- Revision:
- 0:286582877314
- Child:
- 1:11a670498598
File content as of revision 0:286582877314:
//----------------------------------------------------------------------------- // a sample mbed library to play back wave files using MODDMA // Based on the wave_player library by Steve Ravet and the // MODDMA library by Andy Kirkham. // // The wave_player library is located here: // https://developer.mbed.org/users/sravet/code/wave_player/ // // The MODDMA library is located here: // https://developer.mbed.org/users/AjK/code/MODDMA/ // A wiki page and example are located here: // https://developer.mbed.org/cookbook/MODDMA // // explanation of wave file format. // https://ccrma.stanford.edu/courses/422/projects/WaveFormat/ // if VERBOSE is uncommented then the wave player will enter a verbose // mode that displays all data values as it reads them from the file // and writes them to the DAC. Very slow and unusable output on the DAC, // but useful for debugging wave files that don't work. //#define VERBOSE #include <mbed.h> #include <stdio.h> #include <wave_player.h> //----------------------------------------------------------------------------- // constructor -- accepts an mbed pin to use for AnalogOut. Only p18 will work wave_player::wave_player(AnalogOut *_dac) { wave_DAC=_dac; wave_DAC->write_u16(32768); //DAC is 0-3.3V, so idles at ~1.6V verbosity=0; } //----------------------------------------------------------------------------- // if verbosity is set then wave player enters a mode where the wave file // is decoded and displayed to the screen, including sample values put into // the DAC FIFO, and values read out of the DAC FIFO by the ISR. The DAC output // itself is so slow as to be unusable, but this might be handy for debugging // wave files that don't play //----------------------------------------------------------------------------- void wave_player::set_verbosity(int v) { verbosity=v; } //----------------------------------------------------------------------------- // player function. Takes a pointer to an opened wave file. The file needs // to be stored in a filesystem with enough bandwidth to feed the wave data. // LocalFileSystem isn't, but the SDcard is, at least for 22kHz files. The // SDcard filesystem can be hotrodded by increasing the SPI frequency it uses // internally. //----------------------------------------------------------------------------- void wave_player::play(FILE *wavefile) { unsigned chunk_id,chunk_size,channel; unsigned data,i; unsigned j,k; int dac_cntval; bool buf0_flag; long long slice_value; char *slice_buf; short *data_sptr; unsigned char *data_bptr; int *data_wptr; FMT_STRUCT wav_format; long num_slices; for(i=0; i<BUF_SIZE; i++){ DAC_buf0[i]=0; DAC_buf1[i]=0; } DAC_on=0; int time=0; fread(&chunk_id,4,1,wavefile); fread(&chunk_size,4,1,wavefile); while (!feof(wavefile)) { if (verbosity) printf("Read chunk ID 0x%x, size 0x%x\n",chunk_id,chunk_size); switch (chunk_id) { case 0x46464952: fread(&data,4,1,wavefile); if (verbosity) { 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,wavefile); if (verbosity) { 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(wavefile,chunk_size-sizeof(wav_format),SEEK_CUR); break; case 0x61746164: // allocate a buffer big enough to hold a slice slice_buf=(char *)malloc(wav_format.block_align); if (!slice_buf) { printf("Unable to malloc slice buffer"); exit(1); } num_slices=chunk_size/wav_format.block_align; // Calculating the transfer frequency: // By default, the Mbed library sets the PCLK_DAC clock value // to 24MHz. dac_cntval=(24000000/wav_format.sample_rate); if (verbosity) { printf("DATA chunk\n\r"); printf(" chunk size %d (0x%x)\n\r",chunk_size,chunk_size); printf(" %d slices\n\r",num_slices); printf(" sample rate is %d\r\n", wav_format.sample_rate); printf(" Ideal sample interval=%d\n\r",(unsigned)(1000000.0/wav_format.sample_rate)); printf(" programmed interrupt tick interval=%d\n\r",dac_cntval); } // Prepare the GPDMA system for buffer0. conf0 = new MODDMA_Config; conf0 ->channelNum ( MODDMA::Channel_0 ) ->srcMemAddr ( (uint32_t) &DAC_buf0 ) ->dstMemAddr ( MODDMA::DAC ) ->transferSize ( BUF_SIZE ) ->transferType ( MODDMA::m2p ) ->dstConn ( MODDMA::DAC ) ->attach_tc ( this,&wave_player::TC0_callback ) ->attach_err ( this,&wave_player::ERR0_callback ) ; // config end // Prepare the GPDMA system for buffer1. conf1 = new MODDMA_Config; conf1 ->channelNum ( MODDMA::Channel_1 ) ->srcMemAddr ( (uint32_t) &DAC_buf1 ) ->dstMemAddr ( MODDMA::DAC ) ->transferSize ( BUF_SIZE ) ->transferType ( MODDMA::m2p ) ->dstConn ( MODDMA::DAC ) ->attach_tc ( this,&wave_player::TC1_callback ) ->attach_err ( this,&wave_player::ERR1_callback ) ; // config end LPC_DAC->DACCNTVAL = dac_cntval; // Begin (enable DMA and counter). Note, don't enable // DBLBUF_ENA as we are using DMA double buffering. LPC_DAC->DACCTRL |= (3UL << 2); DAC_on=1; // start reading slices, which contain one sample each for however many channels // are in the wave file. one channel=mono, two channels=stereo, etc. Since // mbed only has a single AnalogOut, all of the channels present are averaged // to produce a single sample value. This summing and averaging happens in // a variable of type signed long long, to make sure that the data doesn't // overflow regardless of sample size (8 bits, 16 bits, 32 bits). // // note that from what I can find that 8 bit wave files use unsigned data, // while 16 and 32 bit wave files use signed data // buf0_flag=1; // Separate slices into sections of BUF_SIZE samples for (j=0; j<((num_slices/BUF_SIZE)+1); j++) { for(k=0; k<BUF_SIZE; k++) { // The last buffer will likely not be exactly BUF_SIZE, // so fill the remaining spots with 0 if((j*BUF_SIZE+k)>num_slices){ if(buf0_flag) DAC_buf0[k]=0; else DAC_buf1[k]=0; } else{ fread(slice_buf,wav_format.block_align,1,wavefile); if (feof(wavefile)) { printf("Oops -- not enough slices in the wave file\n"); exit(1); } data_sptr=(short *)slice_buf; // 16 bit samples data_bptr=(unsigned char *)slice_buf; // 8 bit samples data_wptr=(int *)slice_buf; // 32 bit samples slice_value=0; for (channel=0;channel<wav_format.num_channels;channel++) { switch (wav_format.sig_bps) { case 16: if (verbosity) printf("16 bit channel %d data=%d ",channel,data_sptr[channel]); slice_value+=data_sptr[channel]; break; case 32: if (verbosity) printf("32 bit channel %d data=%d ",channel,data_wptr[channel]); slice_value+=data_wptr[channel]; break; case 8: if (verbosity) printf("8 bit channel %d data=%d ",channel,(int)data_bptr[channel]); slice_value+=data_bptr[channel]; break; } } slice_value/=wav_format.num_channels; // slice_value is now averaged. Next it needs to be scaled to an unsigned 16 bit value // with DC offset so it can be written to the DAC. switch (wav_format.sig_bps) { case 8: slice_value<<=8; break; case 16: slice_value+=32768; break; case 32: slice_value>>=16; slice_value+=32768; break; } if (verbosity) printf("sample %d slice_value %d\n",(j*BUF_SIZE+k),(int)slice_value); if(buf0_flag) DAC_buf0[k]=(uint32_t)slice_value; else DAC_buf1[k]=(uint32_t)slice_value; } } // Except for the first buffer, wait until the previous DMA transfer is // complete before switching buffers if(j>0) { while((dma0_fin_flag==0)&(dma1_fin_flag==0)&(time<500000000)){ wait_us(1); time++; } } if (time>499999999) { printf("timeout, %d of %d\r\n", (j*BUF_SIZE), num_slices); exit(1); } time=0; dma0_fin_flag=0; dma1_fin_flag=0; // If finished filling buffer 0, set flag to fill buffer 1 // and start the DMA transfer for buffer 0 if(buf0_flag==1) { buf0_flag=0; dma.Setup(conf0); dma.Enable( conf0 ); } else // Similarly for buffer 1 { buf0_flag=1; dma.Setup(conf1); dma.Enable( conf1 ); } } DAC_on=0; delete conf0; delete conf1; free(slice_buf); break; case 0x5453494c: if (verbosity) printf("INFO chunk, size %d\n",chunk_size); fseek(wavefile,chunk_size,SEEK_CUR); break; default: printf("unknown chunk type 0x%x, size %d\n",chunk_id,chunk_size); data=fseek(wavefile,chunk_size,SEEK_CUR); break; } fread(&chunk_id,4,1,wavefile); fread(&chunk_size,4,1,wavefile); } } // Configuration callback on TC void wave_player::TC0_callback(void) { // Get configuration pointer. MODDMA_Config *config = dma.getConfig(); dma.haltAndWaitChannelComplete( (MODDMA::CHANNELS)config->channelNum()); // Finish the DMA cycle by shutting down the channel. dma.Disable( (MODDMA::CHANNELS)config->channelNum() ); // Clear DMA IRQ flags. if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq(); // Indicate that buffer 0 has finished transferring dma0_fin_flag=1; } // Configuration callback on Error void wave_player::ERR0_callback(void) { error("Oh no! My Mbed EXPLODED! :( Only kidding, go find the problem"); } // Configuration callback on TC void wave_player::TC1_callback(void) { // Get configuration pointer. MODDMA_Config *config = dma.getConfig(); dma.haltAndWaitChannelComplete( (MODDMA::CHANNELS)config->channelNum()); // Finish the DMA cycle by shutting down the channel. dma.Disable( (MODDMA::CHANNELS)config->channelNum() ); // Clear DMA IRQ flags. if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq(); // Indicate that buffer 1 has finished transferring dma1_fin_flag=1; } // Configuration callback on Error void wave_player::ERR1_callback(void) { error("Oh no! My Mbed EXPLODED! :( Only kidding, go find the problem"); }