audio.h

00001 #ifndef __included_audio_h
00002 #define __included_audio_h
00003 
00004 #include <stdint.h>
00005 
00006 #ifndef AUDIO_DAC_PIN
00007 #define AUDIO_DAC_PIN PTE30          // J10/11 on FRDM-KL25Z
00008 #endif
00009 
00010 namespace NKAudio
00011 {
00012 
00013 struct AudioFile
00014 {
00015     const unsigned char *data;
00016     unsigned int length;
00017 };
00018 
00019 extern const AudioFile audioFiles[];
00020 
00021 // Analog:
00022 // GND   J3/14
00023 // VrefH J3/16
00024 // output J10/11, PTE30
00025 
00026 const unsigned SAMPLE_RATE_HZ         = 8000;
00027 const unsigned SAMPLE_PERIOD_US       = (1000000U / SAMPLE_RATE_HZ);
00028 const unsigned SAMPLE_BUFFER_SIZE     = 14000;
00029 const unsigned AUDIO_WAIT_DURATION_US = 10000;
00030 const uint16_t DC_BIAS                = 0x8000;
00031 
00032 typedef void (*AudioCallback)();
00033 
00034 class AudioPlayer
00035 {
00036 public:
00037     static unsigned numberOfFiles()
00038     {
00039         static unsigned nFiles;
00040         if (!nFiles) {  // count files first time
00041             for (AudioFile const *p = audioFiles; p->data != NULL; p++) {
00042                 nFiles++;
00043             }
00044         } else {
00045             return nFiles;
00046         }
00047     }
00048 
00049     static bool playFileNumbered(unsigned n, AudioCallback cb = NULL)
00050     {
00051         n %= numberOfFiles();
00052         return playAudio(reinterpret_cast<int8_t const * const>(audioFiles[n].data), audioFiles[n].length, cb);
00053     }
00054 
00055     static bool playAudio(int8_t const *start, uint16_t nsamples, AudioCallback cb = 0);
00056 
00057     static bool audioDone() { return !samplesRemaining; }
00058 
00059 private:
00060     static void playAudioSample();
00061     static int8_t const * volatile nextSample;
00062     static uint16_t volatile samplesRemaining;
00063 };
00064 
00065 } // namespace NKAudio
00066 
00067 #endif