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
Diff: wave_player.cpp
- Revision:
- 0:286582877314
- Child:
- 1:11a670498598
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/wave_player.cpp Wed Mar 16 03:28:44 2016 +0000 @@ -0,0 +1,346 @@ +//----------------------------------------------------------------------------- +// 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"); +}