Update voice to use Arcada timer

Author: PaintYourDragon

M4_Eyes/M4_Eyes.ino

@@ -118,6 +118,7 @@ static inline uint16_t readBoop(void) {
 
 // Crude error handler. Prints message to Serial Monitor, blinks LED.
 void fatal(const char *message, uint16_t blinkDelay) {
+  Serial.begin(9600);
   Serial.println(message);
   for(bool ledState = HIGH;; ledState = !ledState) {
     digitalWrite(LED_BUILTIN, ledState);
@@ -135,13 +136,9 @@ uint32_t availableRAM(void) {
 // SETUP FUNCTION - CALLED ONCE AT PROGRAM START ---------------------------
 
 void setup() {
-  if (!arcada.arcadaBegin()) {
-    while (1);
-  }
+  if(!arcada.arcadaBegin())     fatal("Arcada init fail!", 100);
 
-  if (!arcada.filesysBeginMSD()) {
-    fatal("No filesystem found!", 100);
-  }
+  if(!arcada.filesysBeginMSD()) fatal("No filesystem found!", 250);
 
   arcada.displayBegin();
 

M4_Eyes/pdmvoice.cpp

@@ -3,18 +3,15 @@
 
 #if defined(ADAFRUIT_MONSTER_M4SK_EXPRESS)
 
+#include "globals.h"
 #include <SPI.h>
 
 #define MIN_PITCH_HZ   65
 #define MAX_PITCH_HZ 1600
 #define TYP_PITCH_HZ  175
 
-// Playback timer stuff - use TC3 on MONSTER M4SK (no TC4 on this board)
-#define TIMER             TC3
-#define TIMER_IRQN        TC3_IRQn
-#define TIMER_IRQ_HANDLER TC3_Handler
-#define TIMER_GCLK_ID     TC3_GCLK_ID
-#define TIMER_GCM_ID      GCM_TC2_TC3
+static void  voiceOutCallback(void);
+static float actualPlaybackRate;
 
 // PDM mic allows 1.0 to 3.25 MHz max clock (2.4 typical).
 // SPI native max is is 24 MHz, so available speeds are 12, 6, 3 MHz.
@@ -150,38 +147,8 @@ bool voiceSetup(bool modEnable) {
 
   analogWriteResolution(12);
 
-  // Feed TIMER off GCLK1 (already set to 48 MHz by Arduino core)
-  GCLK->PCHCTRL[TIMER_GCLK_ID].bit.CHEN = 0;     // Disable channel
-  while(GCLK->PCHCTRL[TIMER_GCLK_ID].bit.CHEN);  // Wait for disable
-  GCLK_PCHCTRL_Type pchctrl;
-  pchctrl.bit.GEN                       = GCLK_PCHCTRL_GEN_GCLK1_Val;
-  pchctrl.bit.CHEN                      = 1;
-  GCLK->PCHCTRL[TIMER_GCLK_ID].reg      = pchctrl.reg;
-  while(!GCLK->PCHCTRL[TIMER_GCLK_ID].bit.CHEN); // Wait for enable
-
-  // Disable timer before configuring it
-  TIMER->COUNT16.CTRLA.bit.ENABLE       = 0;
-  while(TIMER->COUNT16.SYNCBUSY.bit.ENABLE);
-
-  // 16-bit counter mode, 1:1 prescale, match-frequency generation mode
-  TIMER->COUNT16.CTRLA.bit.MODE      = TC_CTRLA_MODE_COUNT16;
-  TIMER->COUNT16.CTRLA.bit.PRESCALER = TC_CTRLA_PRESCALER_DIV1_Val;
-  TIMER->COUNT16.WAVE.bit.WAVEGEN    = TC_WAVE_WAVEGEN_MFRQ_Val;
-
-  TIMER->COUNT16.CTRLBCLR.reg        = TC_CTRLBCLR_DIR; // Count up
-  while(TIMER->COUNT16.SYNCBUSY.bit.CTRLB);
-
   voicePitch(1.0); // Set timer interval
 
-  TIMER->COUNT16.INTENSET.reg        = TC_INTENSET_OVF; // Overflow interrupt
-  NVIC_DisableIRQ(TIMER_IRQN);
-  NVIC_ClearPendingIRQ(TIMER_IRQN);
-  NVIC_SetPriority(TIMER_IRQN, 0); // Top priority
-  NVIC_EnableIRQ(TIMER_IRQN);
-
-  TIMER->COUNT16.CTRLA.bit.ENABLE    = 1;    // Enable timer
-  while(TIMER->COUNT16.SYNCBUSY.bit.ENABLE); // Wait for it
-
   return true; // Success
 }
 
@@ -196,12 +163,13 @@ bool voiceSetup(bool modEnable) {
 // adjustment (after appying constraints) will be returned.
 float voicePitch(float p) {
   float   desiredPlaybackRate = sampleRate * p;
-  int32_t period = (int32_t)(48000000.0 / desiredPlaybackRate + 0.5);
-  if(period > 2500)     period = 2500; // Hard limit is 65536, 2.5K is a practical limit
-  else if(period < 250) period =  250; // Leave some cycles for IRQ handler
-  TIMER->COUNT16.CC[0].reg = period - 1;
-  while(TIMER->COUNT16.SYNCBUSY.bit.CC0);
-  float   actualPlaybackRate = 48000000.0 / (float)period;
+  // Clip to sensible range
+  if(desiredPlaybackRate < 19200)       desiredPlaybackRate = 19200;  // ~0.41X
+  else if(desiredPlaybackRate > 192000) desiredPlaybackRate = 192000; // ~4.1X
+  arcada.timerCallback(desiredPlaybackRate, voiceOutCallback);
+  // Making this assumption here knowing Arcada will use 1:1 prescale:
+  int32_t period = (int32_t)(48000000.0 / desiredPlaybackRate);
+  actualPlaybackRate = 48000000.0 / (float)period;
   p = (actualPlaybackRate / sampleRate); // New pitch
   jumpThreshold = (int)(jump * p + 0.5);
   return p;
@@ -223,10 +191,8 @@ void voiceGain(float g) {
 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;     // Audio out timer ticks
-    float    playbackRate = 48000000.0 / (float)period; // Audio out samples/sec
-    modLen = (int)(playbackRate / freq + 0.5);
-    if(modLen < 2) modLen = 2;
+    modLen = (int)(actualPlaybackRate / freq + 0.5);
+    if(modLen   < 2) modLen   = 2;
     if(waveform > 4) waveform = 4;
     modWave = waveform;
     yield();
@@ -397,9 +363,7 @@ void PDM_SERCOM_HANDLER(void) {
   evenWord ^= 1;
 }
 
-// Playback timer interrupt
-void TIMER_IRQ_HANDLER(void) {
-  TIMER->COUNT16.INTFLAG.reg = TC_INTFLAG_OVF;
+static void voiceOutCallback(void) {
 
   // Modulation is done on the output (rather than the input) because
   // pitch-shifting modulated input would cause weird waveform
@@ -443,7 +407,7 @@ void TIMER_IRQ_HANDLER(void) {
     } else { // Slowed down
       // Playback may underflow recording, need to advance periodically
       int16_t dist = (playbackIndex >= recIndex) ?
-        (playbackIndex - recIndex) : (recBufSize - (recIndex - playbackIndex));
+        (playbackIndex - recIndex) : (recBufSize - 1 - (recIndex - playbackIndex));
       if(dist <= jumpThreshold) {
         playbackIndexJumped = (playbackIndex + jump) % recBufSize;
         jumping             = true;

M4_Eyes/user.cpp

@@ -1,3 +1,5 @@
+#if 0 // Change to 1 to enable this code (enable only ONE user*.cpp!)
+
 // This file provides a crude way to "drop in" user code to the eyes,
 // allowing concurrent operations without having to maintain a bunch of
 // special derivatives of the eye code (which is still undergoing a lot
@@ -63,3 +65,5 @@ void user_loop(void) {
   }
 */
 }
+
+#endif // 0

M4_Eyes/user_servo.cpp

@@ -0,0 +1,17 @@
+#if 0 // Change to 1 to enable this code (enable only ONE user*.cpp!)
+
+#include <Arduino.h>
+#include <Servo.h>
+
+Servo myservo;
+
+void user_setup(void) {
+  myservo.attach(3);
+}
+
+void user_loop(void) {
+  int pos = map(millis() % 2000, 0, 2000, 0, 180);
+  myservo.write(pos);
+}
+
+#endif // 0