Merge pull request #457 from lancaster-university/audio-refactor

Audio refactor

Author: microbit-carlos

.github/workflows/build.yml

@@ -45,6 +45,8 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: 'lancaster-university/microbit-v2-samples'
+          # FIXME: Temporarily check out the audio-refactor branch for testing
+          ref: 'audio-refactor'
       # We need to use the checkout action (instead of build.py cloning the
       # repository) so that on PRs we can get the commit from the PR merge
       - name: Clone this repository in the libraries folder

.github/workflows/micropython.yml

@@ -16,12 +16,16 @@ jobs:
         with:
           repository: 'microbit-foundation/micropython-microbit-v2'
           submodules: 'true'
+          # FIXME: Temporarily check out the audio-recording branch for testing
+          ref: 'audio-recording'
       - name: Manually clone microbit-v2-samples in the lib/codal/libraries folder
         uses: actions/checkout@v4
         with:
           path: lib/codal/libraries/codal-microbit-v2
           fetch-depth: '0'
           submodules: 'recursive'
+          # FIXME: Temporarily check out the audio-recording branch for testing
+          ref: 'audio-refactor'
       - name: Setup arm-none-eabi-gcc v10.3
         uses: carlosperate/arm-none-eabi-gcc-action@v1
         with:

.github/workflows/size-diff.yml

@@ -47,7 +47,9 @@ jobs:
           repository: 'lancaster-university/microbit-v2-samples'
           # Unless manually triggered via workflow_dispatch this will be an empty
           # string, checking out the default branch
-          ref: ${{ github.event.inputs.samples-commit }}
+          # FIXME: Temporarily check out the audio-refactor branch for testing
+          # ref: ${{ github.event.inputs.samples-commit }}
+          ref: 'audio-refactor'
       # We need to use the checkout action (instead of build.py cloning the
       # repository) so that on PRs we can get the commit from the PR merge
       - name: Clone this repository in the libraries folder

inc/MicroBitAudio.h

@@ -28,6 +28,7 @@ DEALINGS IN THE SOFTWARE.
 #include "NRF52PWM.h"
 #include "SoundEmojiSynthesizer.h"
 #include "SoundExpressions.h"
+#include "SampleSource.h"
 #include "Mixer2.h"
 #include "SoundOutputPin.h"
 #include "StreamNormalizer.h"
@@ -39,12 +40,19 @@ DEALINGS IN THE SOFTWARE.
 #define MICROBIT_AUDIO_STATUS_DEEPSLEEP       0x0001
 #define CONFIG_DEFAULT_MICROPHONE_GAIN        0.1f
 
-
 // Configurable options
 #ifndef CONFIG_AUDIO_MIXER_OUTPUT_LATENCY_US
 #define CONFIG_AUDIO_MIXER_OUTPUT_LATENCY_US              (uint32_t) ((CONFIG_MIXER_BUFFER_SIZE/2) * (1000000.0f/44100.0f))
 #endif
 
+#ifndef CONFIG_AUDIO_INPUT_CHANNELS
+#define CONFIG_AUDIO_INPUT_CHANNELS                       4
+#endif
+
+#ifndef CONFIG_AUDIO_DEFAULT_MICROPHONE_SAMPLERATE
+#define CONFIG_AUDIO_DEFAULT_MICROPHONE_SAMPLERATE        11000
+#endif
+
 namespace codal
 {
     /**
@@ -55,12 +63,13 @@ namespace codal
         public:
         static MicroBitAudio    *instance;      // Primary instance of MicroBitAudio, on demand activated.
         Mixer2                  mixer;          // Multi channel audio mixer
-        NRF52ADCChannel *mic;                   // Microphone ADC Channel from uBit.IO
+        NRF52ADCChannel         *mic;           // Microphone ADC Channel from uBit.IO
         StreamNormalizer        *processor;     // Stream Normaliser instance
         StreamSplitter          *splitter;      // Stream Splitter instance (8bit normalized output)
         StreamSplitter          *rawSplitter;   // Stream Splitter instance (raw input)
         LevelDetectorSPL        *levelSPL;      // Level Detector SPL instance
         LowPassFilter           *micFilter;     // Low pass filter to remove high frequency noise on the mic
+        SampleSource            *sampleSource[CONFIG_AUDIO_INPUT_CHANNELS]; // multichannel sample playback capability
 
         private:
         volatile bool micEnabled;               // State of on board mic
@@ -97,12 +106,6 @@ namespace codal
          */
         static void requestActivation();
 
-        /**
-          * Catch events from the splitter
-          * @param MicroBitEvent
-          */
-        void onSplitterEvent(MicroBitEvent);
-
         /**
           * Activate Mic
           */
@@ -190,6 +193,8 @@ namespace codal
           * Puts the component in (or out of) sleep (low power) mode.
           */
         virtual int setSleep(bool doSleep) override;
+
+        virtual void periodicCallback();
     };
 }
 

inc/MicroBitConfig.h

@@ -59,7 +59,7 @@
     #ifdef SOFTDEVICE_PRESENT
         #define MICROBIT_STORAGE_PAGE           ( MICROBIT_BOOTLOADER_ADDRESS - MICROBIT_CODEPAGESIZE * 3)
     #else
-        #define MICROBIT_STORAGE_PAGE           ( 0x7F000 )
+        #define MICROBIT_STORAGE_PAGE           ( 0x0007F000 )
     #endif
 #endif
 
@@ -68,7 +68,11 @@
 #endif
 
 #ifndef MICROBIT_DEFAULT_SCRATCH_PAGE
-    #define MICROBIT_DEFAULT_SCRATCH_PAGE   ( MICROBIT_BOOTLOADER_ADDRESS - MICROBIT_CODEPAGESIZE * 4)
+    #ifdef SOFTDEVICE_PRESENT
+        #define MICROBIT_DEFAULT_SCRATCH_PAGE   ( MICROBIT_BOOTLOADER_ADDRESS - MICROBIT_CODEPAGESIZE * 4)
+    #else
+        #define MICROBIT_DEFAULT_SCRATCH_PAGE   ( 0x0007E000 )
+    #endif
 #endif
 
 #ifndef MICROBIT_STORAGE_SCRATCH_PAGE
@@ -87,6 +91,13 @@
     #endif
 #endif
 
+#ifndef MICROBIT_TOP_OF_FLASH
+    #ifdef SOFTDEVICE_PRESENT
+        #define MICROBIT_TOP_OF_FLASH   ( 0x00073000 )
+    #else
+        #define MICROBIT_TOP_OF_FLASH   ( 0x0007E000 )
+    #endif
+#endif
 
 #ifndef MICROBIT_APP_REGION_END
     #define MICROBIT_APP_REGION_END         ( MICROBIT_DEFAULT_SCRATCH_PAGE)

inc/Mixer2.h

@@ -165,7 +165,7 @@ class Mixer2 : public DataSource
      * @param sampleRate (samples per second) - if set to zero, defaults to the output sample rate of the Mixer
      * @param sampleRange (quantization levels) the difference between the maximum and minimum sample level on the input channel
      */
-    MixerChannel *addChannel(DataSource &stream, float sampleRate = CONFIG_MIXER_DEFAULT_CHANNEL_SAMPLERATE, int sampleRange = CONFIG_MIXER_INTERNAL_RANGE);
+    MixerChannel *addChannel(DataSource &stream, float sampleRate = 0.0f, int sampleRange = CONFIG_MIXER_INTERNAL_RANGE);
 
     /**
      * Removes a channel from the mixer

inc/SampleSource.h

@@ -0,0 +1,37 @@
+#ifndef SAMPLE_SOURCE_H
+#define SAMPLE_SOURCE_H
+
+#include "MemorySource.h"
+#include "DataStream.h"
+#include "Mixer2.h"
+
+namespace codal
+{
+    class SampleSource : public MemorySource
+    {
+        private:
+        Mixer2 &mixer;
+        float sampleRate;
+        float sampleRange;
+        MixerChannel *channel;
+
+        public:
+            /**
+             * Constructor.
+             * Creates an empty sample source with a Mixer.
+             * = CONFIG_MIXER_DEFAULT_SAMPLERATE
+             */
+            SampleSource(Mixer2 &mixer, float sampleRate, float sampleRange);
+
+            /**
+             * Destructor
+             * Removes all resources held by the instance
+             */
+            ~SampleSource();
+
+            void setSampleRate(float sampleRate);
+
+            void setVolume(float volume);
+    };
+}
+#endif

model/MicroBit.cpp

@@ -201,6 +201,7 @@ int MicroBit::init()
     // which saves processor time, memeory and battery life.
     messageBus.listen(DEVICE_ID_MESSAGE_BUS_LISTENER, DEVICE_EVT_ANY, this, &MicroBit::onListenerRegisteredEvent);
     messageBus.listen(DEVICE_ID_MESSAGE_BUS_LISTENER, ID_PIN_P0, this, &MicroBit::onP0ListenerRegisteredEvent, MESSAGE_BUS_LISTENER_IMMEDIATE);
+    messageBus.listen(DEVICE_ID_MESSAGE_BUS_IGNORED, DEVICE_EVT_ANY, this, &MicroBit::onListenerRemovedEvent);
 
 #if CONFIG_ENABLED(DMESG_SERIAL_DEBUG) && DEVICE_DMESG_BUFFER_SIZE > 0
     codal_dmesg_set_flush_fn(microbit_dmesg_flush);
@@ -301,7 +302,6 @@ int MicroBit::init()
     // before any user code begins running.
 
     sleep(10);
-
     return DEVICE_OK;
 }
 
@@ -365,7 +365,7 @@ void MicroBit::onListenerRegisteredEvent(Event evt)
             // The level detector uses lazy instantiation, we just need to read the data once to start it running.
             //audio.level->getValue();
             // The level detector requires that we enable constant listening, otherwise no events will be emitted.
-            audio.levelSPL->activateForEvents( true );
+            audio.levelSPL->listenerAdded();
             break;
 
         case DEVICE_ID_MICROPHONE:
@@ -376,6 +376,22 @@ void MicroBit::onListenerRegisteredEvent(Event evt)
     }
 }
 
+/**
+  * A listener to perform actions as a result of Message Bus reflection.
+  *
+  * This callback is triggered upon a MessageBus listneer being removed.
+  * We may wish to perform cleanup operations as a result, etc.
+  *
+  */
+void MicroBit::onListenerRemovedEvent(Event evt)
+{
+    switch(evt.value)
+    {
+        case DEVICE_ID_SYSTEM_LEVEL_DETECTOR:
+        audio.levelSPL->listenerRemoved();
+        break;
+    }
+}
 
 /**
  * Perfom scheduler idle
@@ -475,3 +491,8 @@ void microbit_dmesg_flush()
 #endif
 }
 
+uint32_t *microbit_top_of_flash()
+{
+    return (uint32_t *) MICROBIT_TOP_OF_FLASH;
+}
+

model/MicroBit.h

@@ -67,6 +67,7 @@ DEALINGS IN THE SOFTWARE.
 #include "StreamNormalizer.h"
 #include "LevelDetector.h"
 #include "LevelDetectorSPL.h"
+#include "SampleSource.h"
 #include "PulseIn.h"
 #include "neopixel.h"
 
@@ -121,6 +122,11 @@ namespace codal
              */
             void onP0ListenerRegisteredEvent(Event evt);
 
+            /**
+             * A callback listener to disable default audio streaming to P0 if an event handler is registered on that pin.
+             */
+            void onListenerRemovedEvent(Event evt);
+
             // Pin ranges used for LED matrix display.
 
         public:
@@ -315,6 +321,7 @@ namespace codal
 }
 
 void microbit_dmesg_flush();
+uint32_t *microbit_top_of_flash();
 
 #if CONFIG_ENABLED(CODAL_USE_GLOBAL_NAMESPACE)
 using namespace codal;

source/MicroBitAudio.cpp

@@ -55,12 +55,17 @@ MicroBitAudio::MicroBitAudio(NRF52Pin &pin, NRF52Pin &speaker, NRF52ADC &adc, NR
     if (MicroBitAudio::instance == NULL)
         MicroBitAudio::instance = this;
 
+    // Request a periodic callback
+    status |= DEVICE_COMPONENT_STATUS_SYSTEM_TICK;
+
     synth.allowEmptyBuffers(true);
 
     mic = adc.getChannel(microphone, false);
-    adc.setSamplePeriod( 1e6 / CONFIG_MIXER_DEFAULT_CHANNEL_SAMPLERATE );
+    mic->setSampleRate(CONFIG_AUDIO_DEFAULT_MICROPHONE_SAMPLERATE);
     mic->setGain(7, 0);
 
+    activateMic();
+
     // Implementers note: The order that the pipeline comes up here is quite sensitive. If we connect up to splitters after starting to
     // listen for events from them, we'll see channel startup events (which are valid!) that we don't want. So roughly always follow
     // the following schema:
@@ -73,46 +78,48 @@ MicroBitAudio::MicroBitAudio(NRF52Pin &pin, NRF52Pin &speaker, NRF52ADC &adc, NR
 
     //Initilise input splitter
     rawSplitter = new StreamSplitter(mic->output);
+    rawSplitter->filterOn(&micEnabled);
 
     //Initilise stream normalizer
     processor = new StreamNormalizer(*rawSplitter->createChannel(), 0.08f, true, DATASTREAM_FORMAT_8BIT_SIGNED, 10);
 
     //Initilise level detector SPL and attach to splitter
     //levelSPL = new LevelDetectorSPL(*rawSplitter->createChannel(), 85.0, 65.0, 16.0, 0, DEVICE_ID_MICROPHONE, false);
-    levelSPL = new LevelDetectorSPL(*rawSplitter->createChannel(), 85.0, 65.0, 16.0, 52.0, DEVICE_ID_SYSTEM_LEVEL_DETECTOR, false);
-
-    // Connect to the rawSplitter. This must come AFTER the processor, to prevent the processor's channel activation starting the microphone
-    if(EventModel::defaultEventBus)
-        EventModel::defaultEventBus->listen(rawSplitter->id, DEVICE_EVT_ANY, this, &MicroBitAudio::onSplitterEvent, MESSAGE_BUS_LISTENER_IMMEDIATE);
+    levelSPL = new LevelDetectorSPL(*rawSplitter->createChannel(), 85.0, 65.0, 16.0, 35.0f, DEVICE_ID_SYSTEM_LEVEL_DETECTOR);
 
     //Initilise stream splitter
     splitter = new StreamSplitter(processor->output, DEVICE_ID_SPLITTER);
 
-    // Connect to the splitter - this COULD come after we create it, before we add any stages, as these are dynamic and will only connect on-demand, but just in case
-    // we're going to follow the schema set out above, to be 100% sure.
-    if(EventModel::defaultEventBus) {
-        EventModel::defaultEventBus->listen(DEVICE_ID_SPLITTER, DEVICE_EVT_ANY, this, &MicroBitAudio::onSplitterEvent, MESSAGE_BUS_LISTENER_IMMEDIATE);
-        EventModel::defaultEventBus->listen(DEVICE_ID_NOTIFY, mic->output.emitFlowEvents(), this, &MicroBitAudio::onSplitterEvent, MESSAGE_BUS_LISTENER_IMMEDIATE);
-    }
+    // Create audio input channels
+    for (int i=0; i<CONFIG_AUDIO_INPUT_CHANNELS; i++)
+        sampleSource[i] = new SampleSource(mixer, 11000, 255);
 }
 
-void MicroBitAudio::onSplitterEvent(MicroBitEvent e){
-    if( mic->output.isFlowing() || (e.value == SPLITTER_ACTIVATE || e.value == SPLITTER_CHANNEL_CONNECT) )
+void MicroBitAudio::periodicCallback()
+{
+    if (mic->isEnabled() && !micEnabled)
+    {
+        //DMESG("MicroBitAudio::periodicCallback: activateMic()...");
         activateMic();
-    else
+    }
+
+    if (!mic->isEnabled() && micEnabled)
+    {
+        //DMESG("MicroBitAudio::periodicCallback: deactivateMic()...");
         deactivateMic();
+    }
 }
 
 void MicroBitAudio::activateMic(){
     runmic.setDigitalValue(1);
     runmic.setHighDrive(true);
     adc.activateChannel(mic);
+    adc.getChannel(microphone, false)->setStartDelay(1);
     this->micEnabled = true;
 }
 
 void MicroBitAudio::deactivateMic(){
     this->micEnabled = false;
-    //mic->disable();
     runmic.setDigitalValue(0);
     runmic.setHighDrive(false);
 }