Merge pull request #854 from adafruit/philb-branch

Add mic gain and some initial work on modulation

Author: PaintYourDragon

M4_Eyes/M4_Eyes.ino

@@ -420,10 +420,11 @@ void setup() {
 
 #if defined(ADAFRUIT_MONSTER_M4SK_EXPRESS)
   if(voiceOn) {
-    if(!voiceSetup()) {
+    if(!voiceSetup(false)) {
       Serial.println("Voice init fail, continuing without");
       voiceOn = false;
     } else {
+      voiceGain(gain);
       currentPitch = voicePitch(currentPitch);
       digitalWrite(20, HIGH); // Speaker on
     }

M4_Eyes/file.cpp

@@ -376,6 +376,7 @@ void loadConfig(char *filename) {
       v = doc["voice"];
       if(v.is<bool>()) voiceOn = v.as<bool>();
       currentPitch = defaultPitch = doc["pitch"] | defaultPitch;
+      gain = doc["gain"] | gain;
 #endif // ADAFRUIT_MONSTER_M4SK_EXPRESS
     }
     file.close();

M4_Eyes/globals.h

@@ -88,6 +88,7 @@ GLOBAL_VAR uint32_t  boopThreshold       GLOBAL_INIT(17500);
 GLOBAL_VAR bool      voiceOn             GLOBAL_INIT(false);
 GLOBAL_VAR float     currentPitch        GLOBAL_INIT(1.0);
 GLOBAL_VAR float     defaultPitch        GLOBAL_INIT(1.0);
+GLOBAL_VAR float     gain                GLOBAL_INIT(1.0);
 #endif
 
 // EYE-RELATED STRUCTURES --------------------------------------------------
@@ -214,9 +215,10 @@ extern uint8_t        *writeDataToFlash(uint8_t *src, uint32_t len);
 
 // Functions in pdmvoice.cpp
 #if defined(ADAFRUIT_MONSTER_M4SK_EXPRESS)
-extern bool              voiceSetup(void);
+extern bool              voiceSetup(bool modEnable);
 extern float             voicePitch(float p);
 extern void              voiceGain(float g);
+extern void              voiceMod(uint32_t freq, uint8_t waveform);
 extern volatile uint16_t voiceLastReading;
 #endif // ADAFRUIT_MONSTER_M4SK_EXPRESS
 

M4_Eyes/pdmvoice.cpp

@@ -76,6 +76,12 @@ static uint16_t       dcOffsetNext     = 32768; // between these two values
 
 static uint16_t       micGain          = 256;   // 1:1
 
+#define MOD_MIN 40 // Lowest supported modulation pitch (lower = more RAM use)
+static uint8_t        modWave          = 0;     // Modulation wave type (none, sine, square, tri, saw)
+static uint8_t       *modBuf           = NULL;  // Modulation waveform buffer
+static uint32_t       modIndex         = 0;     // Current position in modBuf
+static uint32_t       modLen           = 0;     // Currently used amount of modBuf based on modFreq
+
 // Just playing back directly from the recording circular buffer produces
 // audible clicks as the waveforms rarely align at the beginning and end of
 // the buffer. So what we do is advance or push back the playback index a
@@ -100,13 +106,20 @@ float voicePitch(float p);
 
 // START PITCH SHIFT (no arguments) ----------------------------------------
 
-bool voiceSetup(void) {
+bool voiceSetup(bool modEnable) {
 
   // Allocate circular buffer for audio
   if(NULL == (recBuf = (uint16_t *)malloc(recBufSize * sizeof(uint16_t)))) {
     return false; // Fail
   }
 
+  // Allocate buffer for voice modulation, if enabled
+  if(modEnable) {
+    // 250 comes from min period in voicePitch()
+    modBuf = (uint8_t *)malloc((int)(48000000.0 / 250.0 / MOD_MIN + 0.5));
+    // If malloc fails, program will continue without modulation
+  }
+
   // Set up PDM microphone input -------------------------------------------
 
   PDM_SPI.begin();
@@ -202,6 +215,47 @@ void voiceGain(float g) {
   else                     micGain = (uint16_t)(g * 256.0 + 0.5);
 }
 
+// SET MODULATION ----------------------------------------------------------
+
+// This is a work in progress and NOT FUNCTIONAL YET
+
+void voiceMod(uint32_t freq, uint8_t waveform) {
+  if(modBuf) { // Ignore if no modulation buffer allocated
+    if(freq < MOD_MIN) freq = MOD_MIN;
+    uint16_t period = TIMER->COUNT16.CC[0].reg + 1;
+    float    playbackRate = 48000000.0 / (float)period; // samples/sec
+    modLen = (int)(playbackRate / freq + 0.5);
+    if(modLen < 2) modLen = 2;
+    if(waveform > 4) waveform = 4;
+    modWave = waveform;
+    switch(modWave) {
+     case 0: // None
+      memset(modBuf, 255, modLen);
+      break;
+     case 1: // Square
+      memset(modBuf, 255, modLen / 2);
+      memset(&modBuf[modLen / 2], 0, modLen - modLen / 2);
+      break;
+     case 2: // Sine
+      for(int i=0; i<modLen; i++) {
+        modBuf[i] = (int)((sin(M_PI * 2.0 * (float)i / (float)modLen) + 1.0) * 0.5 * 255.0 + 0.5);
+      }
+      break;
+     case 3: // Triangle
+      for(int i=0; i<modLen; i++) {
+        modBuf[i] = (int)(fabs(0.5 - (float)i / (float)modLen) * 2.0 * 255.0 + 0.5);
+      }
+      break;
+     case 4: // Sawtooth (increasing)
+      for(int i=0; i<modLen; i++) {
+        modBuf[i] = (int)((float)i / (float)(modLen - 1) * 255.0 + 0.5);
+      }
+      break;
+    }
+  }
+}
+
+
 // INTERRUPT HANDLERS ------------------------------------------------------
 
 static uint16_t const sincfilter[64] = { 0, 2, 9, 21, 39, 63, 94, 132, 179, 236, 302, 379, 467, 565, 674, 792, 920, 1055, 1196, 1341, 1487, 1633, 1776, 1913, 2042, 2159, 2263, 2352, 2422, 2474, 2506, 2516, 2506, 2474, 2422, 2352, 2263, 2159, 2042, 1913, 1776, 1633, 1487, 1341, 1196, 1055, 920, 792, 674, 565, 467, 379, 302, 236, 179, 132, 94, 63, 39, 21, 9, 2, 0, 0 };
@@ -347,6 +401,11 @@ void PDM_SERCOM_HANDLER(void) {
 void TIMER_IRQ_HANDLER(void) {
   TIMER->COUNT16.INTFLAG.reg = TC_INTFLAG_OVF;
 
+  if(modWave) {
+    nextOut = (((int32_t)nextOut - 2048) * (modBuf[modIndex] + 1) / 256) + 2048;
+    if(++modIndex >= modLen) modIndex = 0;
+  }
+
   // Do analog writes pronto so output timing is consistent
   analogWrite(A0, nextOut);
   analogWrite(A1, nextOut);