Elisabeth Bradley
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
Revision 0:286582877314, committed 2016-03-16
- Comitter:
- ebradley6
- Date:
- Wed Mar 16 03:28:44 2016 +0000
- Child:
- 1:11a670498598
- Commit message:
- Wave player using MODDMA library
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MODDMA.lib Wed Mar 16 03:28:44 2016 +0000 @@ -0,0 +1,1 @@ +http://developer.mbed.org/users/AjK/code/MODDMA/#97a16bf2ff43
--- /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");
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/wave_player.h Wed Mar 16 03:28:44 2016 +0000
@@ -0,0 +1,81 @@
+#include <mbed.h>
+#include "MODDMA.h"
+
+#define BUF_SIZE 1000
+
+typedef struct uFMT_STRUCT {
+ short comp_code;
+ short num_channels;
+ unsigned sample_rate;
+ unsigned avg_Bps;
+ short block_align;
+ short sig_bps;
+} FMT_STRUCT;
+
+
+/** wave file player class.
+ *
+ * Example:
+ * @code
+ * #include <mbed.h>
+ * #include <wave_player.h>
+ *
+ * AnalogOut DACout(p18);
+ * wave_player waver(&DACout);
+ *
+ * int main() {
+ * FILE *wave_file;
+ *
+ * printf("\n\n\nHello, wave world!\n");
+ * wave_file=fopen("/sd/44_8_st.wav","r");
+ * waver.play(wave_file);
+ * fclose(wave_file);
+ * }
+ * @endcode
+ */
+class wave_player {
+
+public:
+/** Create a wave player using a pointer to the given AnalogOut object.
+ *
+ * @param _dac pointer to an AnalogOut object to which the samples are sent.
+ */
+wave_player(AnalogOut *_dac);
+
+/** the player function.
+ *
+ * @param wavefile A pointer to an opened wave file
+ */
+void play(FILE *wavefile);
+
+/** Set the printf verbosity of the wave player. A nonzero verbosity level
+ * will put wave_player in a mode where the complete contents of the wave
+ * file are echoed to the screen, including header values, and including
+ * all of the sample values placed into the DAC FIFO, and the sample values
+ * removed from the DAC FIFO by the ISR. The sample output frequency is
+ * fixed at 2 Hz in this mode, so it's all very slow and the DAC output isn't
+ * very useful, but it lets you see what's going on and may help for debugging
+ * wave files that don't play correctly.
+ *
+ * @param v the verbosity level
+ */
+void set_verbosity(int v);
+
+private:
+int verbosity;
+AnalogOut *wave_DAC;
+MODDMA dma;
+MODDMA_Config *conf0;
+MODDMA_Config *conf1;
+short DAC_on;
+uint32_t DAC_buf0[BUF_SIZE];
+uint32_t DAC_buf1[BUF_SIZE];
+void TC0_callback(void);
+void ERR0_callback(void);
+void TC1_callback(void);
+void ERR1_callback(void);
+bool dma0_fin_flag;
+bool dma1_fin_flag;
+};
+
+