From 774cfb8cef40171a60312411dd0814fab1e8fb9e Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Mon, 19 Feb 2024 21:52:36 -0500
Subject: [PATCH 01/15] adding arduino examples to test interrupt timing

---
 .../GpioInterruptLogger.ino                   | 99 +++++++++++++++++++
 .../InterruptBasedGpioToggle.ino              | 17 ++++
 2 files changed, 116 insertions(+)
 create mode 100644 testing/GpioInterruptLogger/GpioInterruptLogger.ino
 create mode 100644 testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino

diff --git a/testing/GpioInterruptLogger/GpioInterruptLogger.ino b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
new file mode 100644
index 00000000..1c08d19f
--- /dev/null
+++ b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
@@ -0,0 +1,99 @@
+// COde to read the timestamp of 1KHz wave
+//#define DEBUG_SERIAL
+#ifdef ARDUINO_FEATHER_ESP32
+#define PIN_IN 5
+#define PIN_OUT 18
+#elif defined ADAFRUIT_FEATHER_M0
+#define PIN_IN 24
+#define PIN_OUT 23
+#endif
+#include <DoubleBufferFloat.h>
+#include <String.h>
+
+DoubleBufferFloat us_timeBuffer(50);
+DoubleBufferFloat ms_timeBuffer(50);
+#ifdef ARDUINO_FEATHER_ESP32
+void IRAM_ATTR isr() {
+	//counter++;
+  // push to Double Buffer
+  us_timeBuffer.push_back(micros());
+  ms_timeBuffer.push_back(millis());
+  digitalWrite(PIN_OUT, !digitalRead(PIN_OUT));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN
+}
+#elif defined ADAFRUIT_FEATHER_M0
+void isr() {
+	//counter++;
+  // push to Double Buffer
+  us_timeBuffer.push_back(micros());
+  ms_timeBuffer.push_back(millis());
+  digitalWrite(PIN_OUT, !digitalRead(PIN_OUT));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN
+}
+
+#endif
+
+void setup() {
+	Serial.begin(2000000);
+	pinMode(PIN_IN, INPUT);
+  pinMode(PIN_OUT, OUTPUT);
+  #ifdef ARDUINO_FEATHER_ESP32
+	attachInterrupt(PIN_IN, isr, RISING);
+  #elif defined ADAFRUIT_FEATHER_M0
+  attachInterrupt( digitalPinToInterrupt( PIN_IN ), isr, RISING );
+  #endif
+}
+
+void loop() {
+  uint32_t timeNow = millis();
+  float *us_timeData; float *ms_timeData;
+  uint32_t tu, tm; // dummy variables.
+  size_t dataAvailableuS, dataAvailablemS;
+  while(1)
+  {
+    if(millis() - timeNow > 200)
+    {
+      #ifdef DEBUG_SERIAL
+      Serial.println("timeNow > millis()");
+      #endif
+      timeNow = millis();
+      #ifdef DEBUG_SERIAL
+      Serial.println("swapping buffer");
+      #endif
+      us_timeBuffer.swap(); // swap buffers before reading
+      ms_timeBuffer.swap(); // swap buffers before reading
+      #ifdef DEBUG_SERIAL
+      Serial.println("swapped buffer");
+      #endif
+      // get the data
+      #ifdef DEBUG_SERIAL
+      Serial.println("getting data");
+      #endif
+      dataAvailableuS = us_timeBuffer.getData(&us_timeData, &tu, false);
+      dataAvailablemS = ms_timeBuffer.getData(&ms_timeData, &tm, false);
+      #ifdef DEBUG_SERIAL
+      Serial.println("got data");
+      #endif
+      if(dataAvailableuS == dataAvailablemS)
+      {
+        #ifdef DEBUG_SERIAL
+        Serial.print("dataAvailableuS"); Serial.println(dataAvailableuS);
+        #endif
+        for (uint8_t i = 0; i < dataAvailableuS; i++) 
+        {
+          String str = String(ms_timeData[i]) + ":" + String(us_timeData[i])  ;
+          Serial.println(str); 
+        }
+      }
+      else
+      {
+        Serial.print("dataAvailableuS: "); Serial.println(dataAvailableuS);
+        Serial.print("dataAvailablemS: "); Serial.println(dataAvailablemS);
+        Serial.println("mismatch in buffer lengths");
+        //while(1);
+      }
+    }
+    else
+    {
+      // do ntohing
+    }
+  }
+}
\ No newline at end of file
diff --git a/testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino b/testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino
new file mode 100644
index 00000000..968d634c
--- /dev/null
+++ b/testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino
@@ -0,0 +1,17 @@
+// Code to create a sq waveform to test timing accuracy
+#define OUT_PIN 5
+hw_timer_t *My_timer = NULL;
+void IRAM_ATTR onTimer(){
+digitalWrite(OUT_PIN, !digitalRead(OUT_PIN));
+}
+void setup() {
+pinMode(OUT_PIN, OUTPUT);
+My_timer = timerBegin(0, 80, true);
+timerAttachInterrupt(My_timer, &onTimer, true);
+// We want to create a wave with a time period of 6666uS (150Hz)
+// Choose timer to be 1/2 of required time period
+timerAlarmWrite(My_timer, 3333, true); 
+timerAlarmEnable(My_timer); //Just Enable
+}
+void loop() {
+}
\ No newline at end of file

From 74830c9d8932fd25682992d0942db851ee19d67f Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Fri, 1 Mar 2024 19:46:40 -0500
Subject: [PATCH 02/15] added provision for 2 interrupts

---
 .../GpioInterruptLogger.ino                   | 126 +++++++++++-------
 1 file changed, 75 insertions(+), 51 deletions(-)

diff --git a/testing/GpioInterruptLogger/GpioInterruptLogger.ino b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
index 1c08d19f..823eacc9 100644
--- a/testing/GpioInterruptLogger/GpioInterruptLogger.ino
+++ b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
@@ -1,55 +1,101 @@
 // COde to read the timestamp of 1KHz wave
 //#define DEBUG_SERIAL
 #ifdef ARDUINO_FEATHER_ESP32
-#define PIN_IN 5
-#define PIN_OUT 18
+#define PIN_IN_1 5
+#define PIN_OUT_1 18
 #elif defined ADAFRUIT_FEATHER_M0
-#define PIN_IN 24
-#define PIN_OUT 23
+#define PIN_IN_1 24
+#define PIN_OUT_1 23
+#define PIN_IN_2 22
+#define PIN_OUT_2 5
 #endif
 #include <DoubleBufferFloat.h>
 #include <String.h>
 
-DoubleBufferFloat us_timeBuffer(50);
-DoubleBufferFloat ms_timeBuffer(50);
+DoubleBufferFloat us_timeBuffer_IN1(50);
+DoubleBufferFloat ms_timeBuffer_IN1(50);
+DoubleBufferFloat us_timeBuffer_IN2(50);
+DoubleBufferFloat ms_timeBuffer_IN2(50);
 #ifdef ARDUINO_FEATHER_ESP32
-void IRAM_ATTR isr() {
+void IRAM_ATTR isr_pin1() {
 	//counter++;
   // push to Double Buffer
-  us_timeBuffer.push_back(micros());
-  ms_timeBuffer.push_back(millis());
-  digitalWrite(PIN_OUT, !digitalRead(PIN_OUT));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN
+  us_timeBuffer_IN1.push_back(micros());
+  ms_timeBuffer_IN1.push_back(millis());
+  digitalWrite(PIN_OUT_1, !digitalRead(PIN_OUT_1));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN_1
 }
 #elif defined ADAFRUIT_FEATHER_M0
-void isr() {
+void isr_pin1() {
 	//counter++;
   // push to Double Buffer
-  us_timeBuffer.push_back(micros());
-  ms_timeBuffer.push_back(millis());
-  digitalWrite(PIN_OUT, !digitalRead(PIN_OUT));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN
+  us_timeBuffer_IN1.push_back(micros());
+  ms_timeBuffer_IN1.push_back(millis());
+  digitalWrite(PIN_OUT_1, !digitalRead(PIN_OUT_1));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN_1
 }
 
+void isr_pin2() {
+	//counter++;
+  // push to Double Buffer
+  us_timeBuffer_IN2.push_back(micros());
+  ms_timeBuffer_IN2.push_back(millis());
+  digitalWrite(PIN_OUT_2, !digitalRead(PIN_OUT_2));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN_2
+}
 #endif
 
+
+void getData(DoubleBufferFloat *buf_us, DoubleBufferFloat *buf_ms, String pin)
+{
+  float *us_timeData; float *ms_timeData;
+  uint32_t tu, tm; // dummy variables.
+  size_t dataAvailableuS, dataAvailablemS;
+  // get the data
+  #ifdef DEBUG_SERIAL
+  Serial.println("getting data");
+  #endif
+  dataAvailableuS = buf_us->getData(&us_timeData, &tu, false);
+  dataAvailablemiS = buf_ms->getData(&ms_timeData, &tm, false);
+  #ifdef DEBUG_SERIAL
+  Serial.println("got data");
+  #endif
+  if(dataAvailableuS == dataAvailablemS)
+  {
+    #ifdef DEBUG_SERIAL
+    Serial.print("dataAvailableuS"); Serial.println(dataAvailableuS);
+    #endif
+    for (uint8_t i = 0; i < dataAvailableuS; i++) 
+    {
+      String str = pin + ":" + String(ms_timeData[i]) + ":" + String(us_timeData[i])  ;
+      Serial.println(str); 
+    }
+  }
+  else
+  {
+    Serial.print("dataAvailableuS: "); Serial.println(dataAvailableuS);
+    Serial.print("dataAvailablemS: "); Serial.println(dataAvailablemS);
+    Serial.println("mismatch in buffer lengths");
+    //while(1);
+  }
+}
 void setup() {
 	Serial.begin(2000000);
-	pinMode(PIN_IN, INPUT);
-  pinMode(PIN_OUT, OUTPUT);
+	pinMode(PIN_IN_1, INPUT);
+  pinMode(PIN_OUT_1, OUTPUT);
+	pinMode(PIN_IN_2, INPUT);
+  pinMode(PIN_OUT_2, OUTPUT);
   #ifdef ARDUINO_FEATHER_ESP32
-	attachInterrupt(PIN_IN, isr, RISING);
+	attachInterrupt(PIN_IN_1, isr_pin1, RISING);
   #elif defined ADAFRUIT_FEATHER_M0
-  attachInterrupt( digitalPinToInterrupt( PIN_IN ), isr, RISING );
+  attachInterrupt( digitalPinToInterrupt( PIN_IN_1 ), isr_pin1, RISING );
+  attachInterrupt( digitalPinToInterrupt( PIN_IN_2 ), isr_pin2, RISING );
   #endif
 }
 
 void loop() {
   uint32_t timeNow = millis();
-  float *us_timeData; float *ms_timeData;
-  uint32_t tu, tm; // dummy variables.
-  size_t dataAvailableuS, dataAvailablemS;
+
   while(1)
   {
-    if(millis() - timeNow > 200)
+    if(millis() - timeNow > 100)
     {
       #ifdef DEBUG_SERIAL
       Serial.println("timeNow > millis()");
@@ -58,38 +104,16 @@ void loop() {
       #ifdef DEBUG_SERIAL
       Serial.println("swapping buffer");
       #endif
-      us_timeBuffer.swap(); // swap buffers before reading
-      ms_timeBuffer.swap(); // swap buffers before reading
+      us_timeBuffer_IN1.swap(); // swap buffers before reading
+      ms_timeBuffer_IN1.swap(); // swap buffers before reading
+      us_timeBuffer_IN2.swap(); // swap buffers before reading
+      ms_timeBuffer_IN2.swap(); // swap buffers before reading
       #ifdef DEBUG_SERIAL
       Serial.println("swapped buffer");
       #endif
-      // get the data
-      #ifdef DEBUG_SERIAL
-      Serial.println("getting data");
-      #endif
-      dataAvailableuS = us_timeBuffer.getData(&us_timeData, &tu, false);
-      dataAvailablemS = ms_timeBuffer.getData(&ms_timeData, &tm, false);
-      #ifdef DEBUG_SERIAL
-      Serial.println("got data");
-      #endif
-      if(dataAvailableuS == dataAvailablemS)
-      {
-        #ifdef DEBUG_SERIAL
-        Serial.print("dataAvailableuS"); Serial.println(dataAvailableuS);
-        #endif
-        for (uint8_t i = 0; i < dataAvailableuS; i++) 
-        {
-          String str = String(ms_timeData[i]) + ":" + String(us_timeData[i])  ;
-          Serial.println(str); 
-        }
-      }
-      else
-      {
-        Serial.print("dataAvailableuS: "); Serial.println(dataAvailableuS);
-        Serial.print("dataAvailablemS: "); Serial.println(dataAvailablemS);
-        Serial.println("mismatch in buffer lengths");
-        //while(1);
-      }
+      getData(&us_timeBuffer_IN1, &ms_timeBuffer_IN1, String("PIN_1"));
+      getData(&us_timeBuffer_IN2, &ms_timeBuffer_IN2, String("PIN_2"));
+      
     }
     else
     {

From 1f683d846f4fc036aeefea8dc771817e99c40d1b Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Fri, 1 Mar 2024 19:47:28 -0500
Subject: [PATCH 03/15] init tweak to make it work on 2 cores

---
 EmotiBit.cpp | 60 ++++++++++++++++++++++++++++++++++------------------
 EmotiBit.h   |  9 +++++---
 2 files changed, 45 insertions(+), 24 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index 8b2ed0ee..b0566ed6 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -5,7 +5,7 @@
 
 EmotiBit* myEmotiBit = nullptr;
 void(*onInterruptCallback)(void);
-
+SemaphoreHandle_t _xMutex;
 #ifdef ARDUINO_FEATHER_ESP32
 TaskHandle_t EmotiBitDataAcquisition;
 hw_timer_t * timer = NULL;
@@ -1099,17 +1099,17 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 		startTimer(BASE_SAMPLING_FREQ);
 #elif defined ARDUINO_FEATHER_ESP32
 		// setup timer
-		timer = timerBegin(0, 80, true); // timer ticks with APB timer, which runs at 80MHz. This setting makes the timer tick every 1uS
+		//timer = timerBegin(0, 80, true); // timer ticks with APB timer, which runs at 80MHz. This setting makes the timer tick every 1uS
 
 		// Attach onTimer function to our timer.
-		timerAttachInterrupt(timer, &onTimer, true);
+		//timerAttachInterrupt(timer, &onTimer, true);
 
 		// Set alarm to call onTimer function (value in microseconds).
 		// Repeat the alarm (third parameter)
-		timerAlarmWrite(timer, 1000000 / BASE_SAMPLING_FREQ, true);
+		//timerAlarmWrite(timer, 1000000 / BASE_SAMPLING_FREQ, true);
 
 		// Start an alarm
-		timerAlarmEnable(timer);
+		//timerAlarmEnable(timer);
 
 		attachToCore(&ReadSensors, this);
 #endif
@@ -1597,6 +1597,7 @@ void EmotiBit::updateButtonPress()
 
 uint8_t EmotiBit::update()
 {
+	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_1, HIGH);
 	if (testingMode == TestingMode::FACTORY_TEST)
 	{
 		processFactoryTestMessages();
@@ -1671,7 +1672,7 @@ uint8_t EmotiBit::update()
 	if (millis() - dataSendTimer > DATA_SEND_INTERVAL)
 	{
 		dataSendTimer = millis();
-
+		if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, HIGH);
 
 
 		if (_sendTestData)
@@ -1698,6 +1699,7 @@ uint8_t EmotiBit::update()
 				bufferOverflowTest();
 			}
 		}
+		if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, LOW);
 	}
 
 	// Hibernate after writing data
@@ -1729,7 +1731,7 @@ uint8_t EmotiBit::update()
 			sleep();
 		}
 	}
-	
+	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_1, LOW);
 	// ToDo: implement logic to determine return val
 	return 0;
 }
@@ -1842,7 +1844,7 @@ int8_t EmotiBit::updateThermopileData() {
 #ifdef DEBUG_THERM_UPDATE
 	Serial.println("updateThermopileData");
 #endif
-	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_1, HIGH);
+	
 	// Thermopile
 	int8_t status = 0;
 	uint32_t timestamp;
@@ -1871,12 +1873,11 @@ int8_t EmotiBit::updateThermopileData() {
 #endif
 			if (thermStatus == MLX90632::status::SENSOR_SUCCESS)
 			{
-				if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, HIGH);
+				
 				timestamp = millis();
 				status = status | therm0AMB.push_back(AMB, &(timestamp));
 				status = status | therm0Sto.push_back(Sto, &(timestamp));
 				thermopile.startRawSensorValues(thermStatus);
-				if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, LOW);
 			}
 			else
 			{
@@ -1897,7 +1898,7 @@ int8_t EmotiBit::updateThermopileData() {
 	}
 	
 	_thermReadFinishedTime = micros();
-	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_1, LOW);
+	
 	return status;
 }
 
@@ -2234,8 +2235,11 @@ bool EmotiBit::processThermopileData()
 	
 	// Swap buffers with minimal delay to avoid size mismatch
 	unsigned long int swapStart = micros();
+	//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
 	therm0AMB.swap();
 	therm0Sto.swap();
+	//xSemaphoreGive( _xMutex );
+
 	unsigned long int swapEnd = micros();
 	//Serial.println("swap: " + String(swapEnd - swapStart));
 	
@@ -2287,7 +2291,9 @@ bool EmotiBit::processThermopileData()
 		// if dummy data was stored
 		if (dataAMB[i] == -2 && dataSto[i] == -2)
 		{
+			//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
 			dataDoubleBuffers[(uint8_t)EmotiBit::DataType::THERMOPILE]->swap();
+			//xSemaphoreGive( _xMutex );
 			return true;
 			//return dataDoubleBuffers[(uint8_t)EmotiBit::DataType::THERMOPILE]->getData(data, timestamp);
 		}
@@ -2351,7 +2357,9 @@ bool EmotiBit::processThermopileData()
 			therm0Sto.getOverflowCount(DoubleBufferFloat::BufferSelector::OUT)
 		)
 	);
+	//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
 	dataDoubleBuffers[(uint8_t)EmotiBit::DataType::THERMOPILE]->swap();
+	//xSemaphoreGive( _xMutex );
 	// ToDo: implement logic to determine return val
 	return true;
 }
@@ -3330,7 +3338,9 @@ void EmotiBit::processData()
 			}
 			else
 			{
+				//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
 				dataDoubleBuffers[t]->swap();
+				//xSemaphoreGive( _xMutex );
 				//Serial.print(String(t) + ",");
 			}
 		}
@@ -4420,9 +4430,9 @@ void attachToCore(void(*readFunction)(void*), EmotiBit*e)
 		"EmotiBitDataAcquisition",     /* name of task. */
 		10000,       /* Stack size of task */
 		NULL,        /* parameter of the task */
-		configMAX_PRIORITIES - 1,           /* priority of the task */
+		5,           /* priority of the task */
 		&EmotiBitDataAcquisition,      /* Task handle to keep track of created task */
-		1);          /* pin task to core 0 */
+		0);          /* pin task to core 0 */
 	delay(500);
 }
 
@@ -4445,18 +4455,26 @@ void ReadSensors()
 void ReadSensors(void *pvParameters)
 {
 	Serial.print("The data acquisition is executing on core: "); Serial.println(xPortGetCoreID());
+	uint32_t timeLast = micros();
 	while (1) // the function assigned to the second core should never return
 	{
-		if (myEmotiBit != nullptr)
+		if(micros() - timeLast > 6666)
 		{
-			myEmotiBit->readSensors();
-
-		}
-		else
-		{
-			Serial.println("EmotiBit is nullptr");
+			timeLast = micros();
+			if (myEmotiBit != nullptr)
+			{
+				//xSemaphoreTake( myEmotiBit->_xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+				myEmotiBit->readSensors();
+				//xSemaphoreGive( myEmotiBit->_xMutex );
+			}
+			else
+			{
+				Serial.println("EmotiBit is nullptr");
+			}
+			//vTaskSuspend(NULL);
+			vTaskDelay(pdMS_TO_TICKS(1));
 		}
-		vTaskSuspend(NULL);
+		
 	}
 
 }
diff --git a/EmotiBit.h b/EmotiBit.h
index b3052220..709f6c05 100644
--- a/EmotiBit.h
+++ b/EmotiBit.h
@@ -50,14 +50,14 @@ class EmotiBit {
 
 
 
-  String firmware_version = "1.9.0";
+  String firmware_version = "1.9.0.feat-2Core";
 
 
 
 	TestingMode testingMode = TestingMode::NONE;
-	const bool DIGITAL_WRITE_DEBUG = false;
+	const bool DIGITAL_WRITE_DEBUG = true;
 #if defined (ARDUINO_FEATHER_ESP32)
-	const uint8_t DEBUG_OUT_PIN_0 = 26;
+	const uint8_t DEBUG_OUT_PIN_0 = 21;
 	const uint8_t DEBUG_OUT_PIN_1 = 33;
 	const uint8_t DEBUG_OUT_PIN_2 = 15;
 #elif defined (ADAFRUIT_FEATHER_M0)
@@ -425,6 +425,7 @@ class EmotiBit {
 	DataType _serialData = DataType::length;
 	volatile bool buttonPressed = false;
 	bool startBufferOverflowTest = false;
+	
 
 	void setupFailed(const String failureMode, int buttonPin = -1);
 	bool setupSdCard();
@@ -673,6 +674,7 @@ class EmotiBit {
 
 	const uint8_t SCOPE_TEST_PIN = A0;
 	bool scopeTestPinOn = false;
+	
 
 };
 
@@ -684,6 +686,7 @@ void ReadSensors();
 void onTimer();
 void attachToCore(void(*readFunction)(void*), EmotiBit*e = nullptr);
 void ReadSensors(void* pvParameters);
+
 #endif
 
 

From 39e432ca5ffdcff7bc839ede14d83ff921c6a278 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Sat, 2 Mar 2024 00:47:24 -0500
Subject: [PATCH 04/15] working on 2 cores! moved acquisition on core 1 and
 process-update to core 0. Now WiFi does not interrupt acquisition task

---
 EmotiBit.cpp                                  | 40 ++++++++++++++++++-
 EmotiBit.h                                    |  6 ++-
 .../EmotiBit_stock_firmware.ino               |  5 ++-
 3 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index b0566ed6..d717a5a0 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -1112,6 +1112,7 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 		//timerAlarmEnable(timer);
 
 		attachToCore(&ReadSensors, this);
+		attachProcessToCore(&Process);
 #endif
 	}
 
@@ -4421,6 +4422,21 @@ void onTimer() {
 
 #ifdef ARDUINO_FEATHER_ESP32
 
+void attachProcessToCore(void(*readFunction)(void*))
+{
+	//attachEmotiBit(e);
+	// assigning readSensors to second core
+	xTaskCreatePinnedToCore(
+		*readFunction,   /* Task function. */
+		"EmotiBitDataProcess",     /* name of task. */
+		32000,       /* Stack size of task */
+		NULL,        /* parameter of the task */
+		1,           /* priority of the task */
+		NULL,      /* Task handle to keep track of created task */
+		0);          /* pin task to core 0 */
+	delay(500);
+}
+
 void attachToCore(void(*readFunction)(void*), EmotiBit*e)
 {
 	attachEmotiBit(e);
@@ -4430,9 +4446,9 @@ void attachToCore(void(*readFunction)(void*), EmotiBit*e)
 		"EmotiBitDataAcquisition",     /* name of task. */
 		10000,       /* Stack size of task */
 		NULL,        /* parameter of the task */
-		5,           /* priority of the task */
+		configMAX_PRIORITIES - 1,           /* priority of the task */
 		&EmotiBitDataAcquisition,      /* Task handle to keep track of created task */
-		0);          /* pin task to core 0 */
+		1);          /* pin task to core 0 */
 	delay(500);
 }
 
@@ -4452,6 +4468,26 @@ void ReadSensors()
 	}
 }
 #elif defined ARDUINO_FEATHER_ESP32
+void Process(void *pvParameter)
+{
+	Serial.print("The data process is executing on core: "); Serial.println(xPortGetCoreID());
+	while(1)
+	{
+		if (myEmotiBit != nullptr)
+		{
+			//xSemaphoreTake( myEmotiBit->_xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+			myEmotiBit->update();
+			//xSemaphoreGive( myEmotiBit->_xMutex );
+		}
+		else
+		{
+			Serial.println("EmotiBit is nullptr");
+		}
+		//vTaskSuspend(NULL);
+		vTaskDelay(pdMS_TO_TICKS(1));
+	}
+}
+
 void ReadSensors(void *pvParameters)
 {
 	Serial.print("The data acquisition is executing on core: "); Serial.println(xPortGetCoreID());
diff --git a/EmotiBit.h b/EmotiBit.h
index 709f6c05..5c36d85a 100644
--- a/EmotiBit.h
+++ b/EmotiBit.h
@@ -50,7 +50,7 @@ class EmotiBit {
 
 
 
-  String firmware_version = "1.9.0.feat-2Core";
+  String firmware_version = "1.9.0.feat-2Core.0";
 
 
 
@@ -425,6 +425,7 @@ class EmotiBit {
 	DataType _serialData = DataType::length;
 	volatile bool buttonPressed = false;
 	bool startBufferOverflowTest = false;
+	bool _freeToSleep = false;
 	
 
 	void setupFailed(const String failureMode, int buttonPin = -1);
@@ -686,7 +687,8 @@ void ReadSensors();
 void onTimer();
 void attachToCore(void(*readFunction)(void*), EmotiBit*e = nullptr);
 void ReadSensors(void* pvParameters);
-
+void Process(void* pvParameters);
+void attachProcessToCore(void(*readFunction)(void*));
 #endif
 
 
diff --git a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
index c9fbebe0..f2b7cdca 100644
--- a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
+++ b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
@@ -52,7 +52,9 @@ void setup()
 void loop()
 {
 	//Serial.println("emotibit.update()");
-	emotibit.update();
+	//emotibit.update();
+	vTaskDelete(NULL);
+	/*
 
 	size_t dataAvailable = emotibit.readData(EmotiBit::DataType::PPG_GREEN, &data[0], dataSize);
 	if (dataAvailable > 0)
@@ -70,4 +72,5 @@ void loop()
 			}
 		}
 	}
+	*/
 }
\ No newline at end of file

From 74564baea018d5ffeb37a3bebf61d489c8196f87 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Sat, 2 Mar 2024 01:10:36 -0500
Subject: [PATCH 05/15] sleep added with wifi off

---
 EmotiBit.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index d717a5a0..52526d58 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -1672,6 +1672,7 @@ uint8_t EmotiBit::update()
 	static uint32_t dataSendTimer = millis();
 	if (millis() - dataSendTimer > DATA_SEND_INTERVAL)
 	{
+		_freeToSleep = false;
 		dataSendTimer = millis();
 		if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, HIGH);
 
@@ -1701,6 +1702,7 @@ uint8_t EmotiBit::update()
 			}
 		}
 		if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, LOW);
+		_freeToSleep = true;
 	}
 
 	// Hibernate after writing data
@@ -4508,7 +4510,16 @@ void ReadSensors(void *pvParameters)
 				Serial.println("EmotiBit is nullptr");
 			}
 			//vTaskSuspend(NULL);
-			vTaskDelay(pdMS_TO_TICKS(1));
+			if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
+			{
+				esp_sleep_enable_timer_wakeup(6000); // every 6.6mS to maintain 150Hz sampling
+				esp_light_sleep_start(); // start light sleep
+			}
+			else
+			{
+				vTaskDelay(pdMS_TO_TICKS(1));
+			}
+			//vTaskDelay(pdMS_TO_TICKS(1));
 		}
 		
 	}

From 6a49e33e25eb7be2284d1ffee501e9f8a2339a8b Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Sat, 2 Mar 2024 22:29:18 -0500
Subject: [PATCH 06/15] remapped DIO toggle section. experimenting with sleep
 time

---
 EmotiBit.cpp | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index 52526d58..b60612d2 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -2956,7 +2956,7 @@ void EmotiBit::readSensors()
 #ifdef DEBUG_GET_DATA
 	Serial.println("readSensors()");
 #endif // DEBUG
-	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_0, HIGH);
+	
 
 	static unsigned long readSensorsBegin = micros();
 	if (_debugMode)
@@ -3236,7 +3236,7 @@ void EmotiBit::readSensors()
 	}
 	if (acquireData.debug) pushData(EmotiBit::DataType::DEBUG, micros() - readSensorsBegin); // Add readSensors processing duration to debugBuffer
 
-	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_0, LOW);
+	
 }
 
 void EmotiBit::processHeartRate()
@@ -4502,7 +4502,9 @@ void ReadSensors(void *pvParameters)
 			if (myEmotiBit != nullptr)
 			{
 				//xSemaphoreTake( myEmotiBit->_xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
 				myEmotiBit->readSensors();
+				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
 				//xSemaphoreGive( myEmotiBit->_xMutex );
 			}
 			else
@@ -4512,8 +4514,10 @@ void ReadSensors(void *pvParameters)
 			//vTaskSuspend(NULL);
 			if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
 			{
-				esp_sleep_enable_timer_wakeup(6000); // every 6.6mS to maintain 150Hz sampling
+				esp_sleep_enable_timer_wakeup(4500); // every 6.6mS to maintain 150Hz sampling
+				//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
 				esp_light_sleep_start(); // start light sleep
+				//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
 			}
 			else
 			{

From 134c6515ebfe04621448682f876d42e69d42bbc7 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Fri, 8 Mar 2024 07:06:20 -0500
Subject: [PATCH 07/15] moved both acquisition and update tasks to core 1 for
 testing

---
 EmotiBit.cpp                                  | 42 ++++++++++++-------
 EmotiBit.h                                    |  4 +-
 .../EmotiBit_stock_firmware.ino               |  9 ++--
 EmotiBit_stock_firmware/platformio.ini        |  2 +-
 4 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index b60612d2..26fd63ab 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -1112,7 +1112,7 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 		//timerAlarmEnable(timer);
 
 		attachToCore(&ReadSensors, this);
-		attachProcessToCore(&Process);
+		//attachProcessToCore(&Process);
 #endif
 	}
 
@@ -1598,7 +1598,7 @@ void EmotiBit::updateButtonPress()
 
 uint8_t EmotiBit::update()
 {
-	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_1, HIGH);
+	
 	if (testingMode == TestingMode::FACTORY_TEST)
 	{
 		processFactoryTestMessages();
@@ -1667,15 +1667,15 @@ uint8_t EmotiBit::update()
 	// NOTE:: An older firmware, v1.2.86 needs to be used to write EDA correction values to V3 (OTP) and below.
 	// Newer FW version can read both NVMs (EEPROM and OTP), but only have write ability for EEPROM
 
-
+	
 	// Handle data buffer reading and sending
 	static uint32_t dataSendTimer = millis();
 	if (millis() - dataSendTimer > DATA_SEND_INTERVAL)
 	{
+		
 		_freeToSleep = false;
 		dataSendTimer = millis();
-		if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, HIGH);
-
+		
 
 		if (_sendTestData)
 		{
@@ -1701,7 +1701,7 @@ uint8_t EmotiBit::update()
 				bufferOverflowTest();
 			}
 		}
-		if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_2, LOW);
+		
 		_freeToSleep = true;
 	}
 
@@ -1734,7 +1734,7 @@ uint8_t EmotiBit::update()
 			sleep();
 		}
 	}
-	if (DIGITAL_WRITE_DEBUG) digitalWrite(DEBUG_OUT_PIN_1, LOW);
+	
 	// ToDo: implement logic to determine return val
 	return 0;
 }
@@ -4433,9 +4433,9 @@ void attachProcessToCore(void(*readFunction)(void*))
 		"EmotiBitDataProcess",     /* name of task. */
 		32000,       /* Stack size of task */
 		NULL,        /* parameter of the task */
-		1,           /* priority of the task */
+		tskIDLE_PRIORITY,           /* priority of the task */
 		NULL,      /* Task handle to keep track of created task */
-		0);          /* pin task to core 0 */
+		1);          /* pin task to core 0 */
 	delay(500);
 }
 
@@ -4494,6 +4494,7 @@ void ReadSensors(void *pvParameters)
 {
 	Serial.print("The data acquisition is executing on core: "); Serial.println(xPortGetCoreID());
 	uint32_t timeLast = micros();
+	uint32_t timeLastProcess_ms = millis();
 	while (1) // the function assigned to the second core should never return
 	{
 		if(micros() - timeLast > 6666)
@@ -4512,16 +4513,27 @@ void ReadSensors(void *pvParameters)
 				Serial.println("EmotiBit is nullptr");
 			}
 			//vTaskSuspend(NULL);
-			if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
+			if(millis() - timeLastProcess_ms > 50)
 			{
-				esp_sleep_enable_timer_wakeup(4500); // every 6.6mS to maintain 150Hz sampling
-				//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
-				esp_light_sleep_start(); // start light sleep
-				//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
+				// every 50mS, run the process task
+				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_1, HIGH);
+				timeLastProcess_ms = millis();
+				vTaskDelay(pdMS_TO_TICKS(1));// give update some time
+				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_1, LOW);
 			}
 			else
 			{
-				vTaskDelay(pdMS_TO_TICKS(1));
+				if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
+				{
+					esp_sleep_enable_timer_wakeup(4500); // every 6.6mS to maintain 150Hz sampling
+					//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
+					esp_light_sleep_start(); // start light sleep
+					//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
+				}
+				else
+				{
+					vTaskDelay(pdMS_TO_TICKS(1));
+				}
 			}
 			//vTaskDelay(pdMS_TO_TICKS(1));
 		}
diff --git a/EmotiBit.h b/EmotiBit.h
index 5c36d85a..7b0e0282 100644
--- a/EmotiBit.h
+++ b/EmotiBit.h
@@ -49,8 +49,8 @@ class EmotiBit {
 	};
 
 
-
-  String firmware_version = "1.9.0.feat-2Core.0";
+  // 1.9.0.feat-2Core.1 - update and acquisition on core 1. WiFi on core 0
+  String firmware_version = "1.9.0.feat-2Core.1";
 
 
 
diff --git a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
index f2b7cdca..4da8053e 100644
--- a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
+++ b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
@@ -52,10 +52,9 @@ void setup()
 void loop()
 {
 	//Serial.println("emotibit.update()");
-	//emotibit.update();
-	vTaskDelete(NULL);
-	/*
-
+	emotibit.update();
+	//vTaskDelete(NULL);
+	
 	size_t dataAvailable = emotibit.readData(EmotiBit::DataType::PPG_GREEN, &data[0], dataSize);
 	if (dataAvailable > 0)
 	{
@@ -72,5 +71,5 @@ void loop()
 			}
 		}
 	}
-	*/
+	
 }
\ No newline at end of file
diff --git a/EmotiBit_stock_firmware/platformio.ini b/EmotiBit_stock_firmware/platformio.ini
index d8e9cbd7..1cfeb420 100644
--- a/EmotiBit_stock_firmware/platformio.ini
+++ b/EmotiBit_stock_firmware/platformio.ini
@@ -9,7 +9,7 @@
 ; https://docs.platformio.org/page/projectconf.html
 [platformio]
 extra_configs = 
-    ../board_feather_m0.ini
+    ;../board_feather_m0.ini
     ../board_feather_esp32.ini
 src_dir = ./
 lib_dir = ../../

From 765f5b03daf2e399e6684215d8459511a97c303c Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Fri, 8 Mar 2024 17:05:47 -0500
Subject: [PATCH 08/15] acquisition on core 1, update on core 0 with wifi,
 emotibit timing test. Emotibit timing checks out in analysis (gsheet)

---
 EmotiBit.cpp                                  | 51 +++++++++++--------
 EmotiBit.h                                    |  2 +-
 .../EmotiBit_stock_firmware.ino               |  3 +-
 3 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index 26fd63ab..72c3d19f 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -1112,7 +1112,7 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 		//timerAlarmEnable(timer);
 
 		attachToCore(&ReadSensors, this);
-		//attachProcessToCore(&Process);
+		attachProcessToCore(&Process);
 #endif
 	}
 
@@ -1672,7 +1672,7 @@ uint8_t EmotiBit::update()
 	static uint32_t dataSendTimer = millis();
 	if (millis() - dataSendTimer > DATA_SEND_INTERVAL)
 	{
-		
+		if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_1, HIGH);
 		_freeToSleep = false;
 		dataSendTimer = millis();
 		
@@ -1703,6 +1703,7 @@ uint8_t EmotiBit::update()
 		}
 		
 		_freeToSleep = true;
+		if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_1, LOW);
 	}
 
 	// Hibernate after writing data
@@ -4433,9 +4434,9 @@ void attachProcessToCore(void(*readFunction)(void*))
 		"EmotiBitDataProcess",     /* name of task. */
 		32000,       /* Stack size of task */
 		NULL,        /* parameter of the task */
-		tskIDLE_PRIORITY,           /* priority of the task */
+		1,           /* priority of the task */
 		NULL,      /* Task handle to keep track of created task */
-		1);          /* pin task to core 0 */
+		0);          /* pin task to core 0 */
 	delay(500);
 }
 
@@ -4494,7 +4495,7 @@ void ReadSensors(void *pvParameters)
 {
 	Serial.print("The data acquisition is executing on core: "); Serial.println(xPortGetCoreID());
 	uint32_t timeLast = micros();
-	uint32_t timeLastProcess_ms = millis();
+	//uint32_t timeLastProcess_ms = millis(); // if update runs on the same core as acquisition
 	while (1) // the function assigned to the second core should never return
 	{
 		if(micros() - timeLast > 6666)
@@ -4513,28 +4514,38 @@ void ReadSensors(void *pvParameters)
 				Serial.println("EmotiBit is nullptr");
 			}
 			//vTaskSuspend(NULL);
-			if(millis() - timeLastProcess_ms > 50)
-			{
-				// every 50mS, run the process task
-				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_1, HIGH);
-				timeLastProcess_ms = millis();
-				vTaskDelay(pdMS_TO_TICKS(1));// give update some time
-				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_1, LOW);
-			}
-			else
-			{
+			// if(millis() - timeLastProcess_ms > 50)
+			// {
+			// 	// every 50mS, run the process task
+				
+			// 	timeLastProcess_ms = millis();
+			// 	vTaskDelay(pdMS_TO_TICKS(1));// give update some time
+				
+			// }
+			// else
+			// {
 				if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
 				{
-					esp_sleep_enable_timer_wakeup(4500); // every 6.6mS to maintain 150Hz sampling
-					//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
-					esp_light_sleep_start(); // start light sleep
-					//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
+					int sleepTime;
+					uint32_t wakeupTimebuffer = 600; // takes cpu 600uS to wake up
+					if((timeLast + 6666) - micros() > wakeupTimebuffer) // more than a 1mS away from next acquisition pulse
+					{
+						sleepTime = (int)(timeLast + 6666) - (int)micros() - (int)wakeupTimebuffer;
+						//Serial.print("sleeping for(uS): "); Serial.println(sleepTime);
+					} 
+					if(sleepTime > wakeupTimebuffer)
+					{
+						esp_sleep_enable_timer_wakeup(sleepTime); // every 6.6mS to maintain 150Hz sampling
+						//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
+						esp_light_sleep_start(); // start light sleep
+						//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
+					}
 				}
 				else
 				{
 					vTaskDelay(pdMS_TO_TICKS(1));
 				}
-			}
+			//}
 			//vTaskDelay(pdMS_TO_TICKS(1));
 		}
 		
diff --git a/EmotiBit.h b/EmotiBit.h
index 7b0e0282..be4ba422 100644
--- a/EmotiBit.h
+++ b/EmotiBit.h
@@ -50,7 +50,7 @@ class EmotiBit {
 
 
   // 1.9.0.feat-2Core.1 - update and acquisition on core 1. WiFi on core 0
-  String firmware_version = "1.9.0.feat-2Core.1";
+  String firmware_version = "1.9.0.feat-2Core.2";
 
 
 
diff --git a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
index 4da8053e..333e40e7 100644
--- a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
+++ b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
@@ -52,9 +52,10 @@ void setup()
 void loop()
 {
 	//Serial.println("emotibit.update()");
-	emotibit.update();
+	//emotibit.update();
 	//vTaskDelete(NULL);
 	
+	// gets run when acquisitoin gives a delay
 	size_t dataAvailable = emotibit.readData(EmotiBit::DataType::PPG_GREEN, &data[0], dataSize);
 	if (dataAvailable > 0)
 	{

From 50598f34e8a127268f2ad33ba25b076093a15268 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Fri, 8 Mar 2024 18:00:16 -0500
Subject: [PATCH 09/15] Added semaphores

---
 EmotiBit.cpp                                  | 42 ++++++++++++-------
 .../EmotiBit_stock_firmware.ino               |  2 +-
 EmotiBit_stock_firmware/platformio.ini        |  2 +-
 3 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index 72c3d19f..7d0cc6d8 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -5,10 +5,10 @@
 
 EmotiBit* myEmotiBit = nullptr;
 void(*onInterruptCallback)(void);
-SemaphoreHandle_t _xMutex;
 #ifdef ARDUINO_FEATHER_ESP32
 TaskHandle_t EmotiBitDataAcquisition;
 hw_timer_t * timer = NULL;
+SemaphoreHandle_t _xMutex;
 #endif
 
 EmotiBit::EmotiBit() 
@@ -1110,7 +1110,7 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 
 		// Start an alarm
 		//timerAlarmEnable(timer);
-
+		_xMutex = xSemaphoreCreateMutex();
 		attachToCore(&ReadSensors, this);
 		attachProcessToCore(&Process);
 #endif
@@ -2239,10 +2239,14 @@ bool EmotiBit::processThermopileData()
 	
 	// Swap buffers with minimal delay to avoid size mismatch
 	unsigned long int swapStart = micros();
-	//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+	#ifdef ARDUINO_FEATHER_ESP32 
+	xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+	#endif
 	therm0AMB.swap();
 	therm0Sto.swap();
-	//xSemaphoreGive( _xMutex );
+	#ifdef ARDUINO_FEATHER_ESP32 
+	xSemaphoreGive( _xMutex );
+	#endif
 
 	unsigned long int swapEnd = micros();
 	//Serial.println("swap: " + String(swapEnd - swapStart));
@@ -2295,9 +2299,13 @@ bool EmotiBit::processThermopileData()
 		// if dummy data was stored
 		if (dataAMB[i] == -2 && dataSto[i] == -2)
 		{
-			//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+			#ifdef ARDUINO_FEATHER_ESP32 
+			xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+			#endif
 			dataDoubleBuffers[(uint8_t)EmotiBit::DataType::THERMOPILE]->swap();
-			//xSemaphoreGive( _xMutex );
+			#ifdef ARDUINO_FEATHER_ESP32
+			xSemaphoreGive( _xMutex );
+			#endif
 			return true;
 			//return dataDoubleBuffers[(uint8_t)EmotiBit::DataType::THERMOPILE]->getData(data, timestamp);
 		}
@@ -2361,9 +2369,13 @@ bool EmotiBit::processThermopileData()
 			therm0Sto.getOverflowCount(DoubleBufferFloat::BufferSelector::OUT)
 		)
 	);
-	//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+	#ifdef ARDUINO_FEATHER_ESP32 
+	xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+	#endif
 	dataDoubleBuffers[(uint8_t)EmotiBit::DataType::THERMOPILE]->swap();
-	//xSemaphoreGive( _xMutex );
+	#ifdef ARDUINO_FEATHER_ESP32 
+	xSemaphoreGive( _xMutex );
+	#endif
 	// ToDo: implement logic to determine return val
 	return true;
 }
@@ -3342,9 +3354,13 @@ void EmotiBit::processData()
 			}
 			else
 			{
-				//xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+				#ifdef ARDUINO_FEATHER_ESP32 
+				xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+				#endif
 				dataDoubleBuffers[t]->swap();
-				//xSemaphoreGive( _xMutex );
+				#ifdef ARDUINO_FEATHER_ESP32
+				xSemaphoreGive( _xMutex );
+				#endif
 				//Serial.print(String(t) + ",");
 			}
 		}
@@ -4478,9 +4494,7 @@ void Process(void *pvParameter)
 	{
 		if (myEmotiBit != nullptr)
 		{
-			//xSemaphoreTake( myEmotiBit->_xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
 			myEmotiBit->update();
-			//xSemaphoreGive( myEmotiBit->_xMutex );
 		}
 		else
 		{
@@ -4503,11 +4517,11 @@ void ReadSensors(void *pvParameters)
 			timeLast = micros();
 			if (myEmotiBit != nullptr)
 			{
-				//xSemaphoreTake( myEmotiBit->_xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
+				xSemaphoreTake( _xMutex, portMAX_DELAY ); // ToDo: look into implications of portAX_DELAY
 				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
 				myEmotiBit->readSensors();
 				if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
-				//xSemaphoreGive( myEmotiBit->_xMutex );
+				xSemaphoreGive( _xMutex );
 			}
 			else
 			{
diff --git a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
index 333e40e7..30ec7f6f 100644
--- a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
+++ b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
@@ -53,9 +53,9 @@ void loop()
 {
 	//Serial.println("emotibit.update()");
 	//emotibit.update();
-	//vTaskDelete(NULL);
 	
 	// gets run when acquisitoin gives a delay
+	// ToDo: assess time slice given to this task once ported to 2-core topology
 	size_t dataAvailable = emotibit.readData(EmotiBit::DataType::PPG_GREEN, &data[0], dataSize);
 	if (dataAvailable > 0)
 	{
diff --git a/EmotiBit_stock_firmware/platformio.ini b/EmotiBit_stock_firmware/platformio.ini
index 1cfeb420..d8e9cbd7 100644
--- a/EmotiBit_stock_firmware/platformio.ini
+++ b/EmotiBit_stock_firmware/platformio.ini
@@ -9,7 +9,7 @@
 ; https://docs.platformio.org/page/projectconf.html
 [platformio]
 extra_configs = 
-    ;../board_feather_m0.ini
+    ../board_feather_m0.ini
     ../board_feather_esp32.ini
 src_dir = ./
 lib_dir = ../../

From 3b222b613af1a1cea3cf25d5a3c26422e7e8a1b6 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Fri, 8 Mar 2024 19:06:34 -0500
Subject: [PATCH 10/15] some cleanup

---
 EmotiBit.cpp | 33 +++++++++++++++++++--------------
 EmotiBit.h   |  6 +++---
 2 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index 7d0cc6d8..efb8e7ba 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -1098,6 +1098,7 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 		//Serial.println("Starting interrupts");
 		startTimer(BASE_SAMPLING_FREQ);
 #elif defined ARDUINO_FEATHER_ESP32
+		// ToDo: remove timer setup once 2 core functionality is verified.
 		// setup timer
 		//timer = timerBegin(0, 80, true); // timer ticks with APB timer, which runs at 80MHz. This setting makes the timer tick every 1uS
 
@@ -1112,7 +1113,7 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 		//timerAlarmEnable(timer);
 		_xMutex = xSemaphoreCreateMutex();
 		attachToCore(&ReadSensors, this);
-		attachProcessToCore(&Process);
+		attachUpdateToCore(&Update);
 #endif
 	}
 
@@ -4434,6 +4435,7 @@ void attachToInterruptTC3(void(*readFunction)(void), EmotiBit* e)
 }
 
 #elif defined ARDUINO_FEATHER_ESP32
+// ToDo: remove this once 2 core functionality is verified.
 void onTimer() {
 	vTaskResume(EmotiBitDataAcquisition);
 }
@@ -4441,7 +4443,7 @@ void onTimer() {
 
 #ifdef ARDUINO_FEATHER_ESP32
 
-void attachProcessToCore(void(*readFunction)(void*))
+void attachUpdateToCore(void(*readFunction)(void*))
 {
 	//attachEmotiBit(e);
 	// assigning readSensors to second core
@@ -4467,7 +4469,7 @@ void attachToCore(void(*readFunction)(void*), EmotiBit*e)
 		NULL,        /* parameter of the task */
 		configMAX_PRIORITIES - 1,           /* priority of the task */
 		&EmotiBitDataAcquisition,      /* Task handle to keep track of created task */
-		1);          /* pin task to core 0 */
+		1);          /* pin task to core 1 */
 	delay(500);
 }
 
@@ -4487,9 +4489,9 @@ void ReadSensors()
 	}
 }
 #elif defined ARDUINO_FEATHER_ESP32
-void Process(void *pvParameter)
+void Update(void *pvParameter)
 {
-	Serial.print("The data process is executing on core: "); Serial.println(xPortGetCoreID());
+	Serial.print("Update is executing on core: "); Serial.println(xPortGetCoreID());
 	while(1)
 	{
 		if (myEmotiBit != nullptr)
@@ -4501,18 +4503,19 @@ void Process(void *pvParameter)
 			Serial.println("EmotiBit is nullptr");
 		}
 		//vTaskSuspend(NULL);
-		vTaskDelay(pdMS_TO_TICKS(1));
+		vTaskDelay(pdMS_TO_TICKS(1));  // Delay added to give time to IDLE task
 	}
 }
 
 void ReadSensors(void *pvParameters)
 {
 	Serial.print("The data acquisition is executing on core: "); Serial.println(xPortGetCoreID());
+	int BASE_TIME_PERIOD = (int)((float) 1000000 / (float) BASE_SAMPLING_FREQ);
 	uint32_t timeLast = micros();
 	//uint32_t timeLastProcess_ms = millis(); // if update runs on the same core as acquisition
 	while (1) // the function assigned to the second core should never return
 	{
-		if(micros() - timeLast > 6666)
+		if(micros() - timeLast > BASE_TIME_PERIOD)
 		{
 			timeLast = micros();
 			if (myEmotiBit != nullptr)
@@ -4541,23 +4544,25 @@ void ReadSensors(void *pvParameters)
 				if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
 				{
 					int sleepTime;
-					uint32_t wakeupTimebuffer = 600; // takes cpu 600uS to wake up
-					if((timeLast + 6666) - micros() > wakeupTimebuffer) // more than a 1mS away from next acquisition pulse
+					// ToDo: get more accurate buffer time
+					uint32_t wakeupTimebuffer = 600; // Empirically derived estimate. Time taken by CPU to wake up
+					// ToDo: move this into a calculateSleepTime() function
+					if((timeLast + BASE_TIME_PERIOD) - micros() > wakeupTimebuffer) // calculate time to sleep
 					{
-						sleepTime = (int)(timeLast + 6666) - (int)micros() - (int)wakeupTimebuffer;
-						//Serial.print("sleeping for(uS): "); Serial.println(sleepTime);
+						sleepTime = (int)(timeLast + BASE_TIME_PERIOD) - (int)micros() - (int)wakeupTimebuffer;
 					} 
+
 					if(sleepTime > wakeupTimebuffer)
 					{
+						// only sleep if we can wake up in time
 						esp_sleep_enable_timer_wakeup(sleepTime); // every 6.6mS to maintain 150Hz sampling
-						//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, HIGH);
 						esp_light_sleep_start(); // start light sleep
-						//if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_0, LOW);
 					}
 				}
 				else
 				{
-					vTaskDelay(pdMS_TO_TICKS(1));
+					// ToDo: Schedule time give to idle task. Check min time before watchdog timer is activated.
+					vTaskDelay(pdMS_TO_TICKS(1));  // if not sleeping, give time to IDLE task
 				}
 			//}
 			//vTaskDelay(pdMS_TO_TICKS(1));
diff --git a/EmotiBit.h b/EmotiBit.h
index be4ba422..c992ee60 100644
--- a/EmotiBit.h
+++ b/EmotiBit.h
@@ -50,7 +50,7 @@ class EmotiBit {
 
 
   // 1.9.0.feat-2Core.1 - update and acquisition on core 1. WiFi on core 0
-  String firmware_version = "1.9.0.feat-2Core.2";
+  String firmware_version = "1.9.0.feat-2Core.3";
 
 
 
@@ -687,8 +687,8 @@ void ReadSensors();
 void onTimer();
 void attachToCore(void(*readFunction)(void*), EmotiBit*e = nullptr);
 void ReadSensors(void* pvParameters);
-void Process(void* pvParameters);
-void attachProcessToCore(void(*readFunction)(void*));
+void Update(void* pvParameters);
+void attachUpdateToCore(void(*readFunction)(void*));
 #endif
 
 

From 460156848dbf5287ccae982e0495f28b270ecbfb Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Tue, 12 Mar 2024 11:00:53 -0400
Subject: [PATCH 11/15] fixed compile issue

---
 testing/GpioInterruptLogger/GpioInterruptLogger.ino | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/testing/GpioInterruptLogger/GpioInterruptLogger.ino b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
index 823eacc9..ff7e6f00 100644
--- a/testing/GpioInterruptLogger/GpioInterruptLogger.ino
+++ b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
@@ -53,7 +53,7 @@ void getData(DoubleBufferFloat *buf_us, DoubleBufferFloat *buf_ms, String pin)
   Serial.println("getting data");
   #endif
   dataAvailableuS = buf_us->getData(&us_timeData, &tu, false);
-  dataAvailablemiS = buf_ms->getData(&ms_timeData, &tm, false);
+  dataAvailablemS = buf_ms->getData(&ms_timeData, &tm, false);
   #ifdef DEBUG_SERIAL
   Serial.println("got data");
   #endif

From 036c310a30e8be58887c09a6fac6f8c5d4569cb6 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Wed, 20 Mar 2024 21:48:29 -0400
Subject: [PATCH 12/15] adding test codes that help in debugging

---
 .../GpioInterruptLogger.ino                   | 25 +++++++++++++++++--
 .../InterruptBasedGpioToggle.ino              | 20 +++++++++++++--
 2 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/testing/GpioInterruptLogger/GpioInterruptLogger.ino b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
index ff7e6f00..9044e679 100644
--- a/testing/GpioInterruptLogger/GpioInterruptLogger.ino
+++ b/testing/GpioInterruptLogger/GpioInterruptLogger.ino
@@ -1,4 +1,23 @@
-// COde to read the timestamp of 1KHz wave
+/**
+ * @file GpioInterruptLogger
+ *
+ * @section description Description
+ * This example can be used to generate timestamps for external events.
+ * A timestamp in mS and uS is generated everytime an interrupt is triggered.
+ *
+ * @section circuit Circuit
+ * - This is written for Feather M0. Tested on Adafruit Feather M0.
+ * - Refer adafruit's documentation on pin details: https://learn.adafruit.com/adafruit-feather-m0-wifi-atwinc1500/pinouts
+ * - Use PIN_IN_1 and PIN_IN_2 as inputs to which external interrupt signals can be attached.
+ * - PIN_OUT_1 and PIN_OUT_2 toggle at half the frequeny input pins, respectively. (Useful if probing with an Digital Oscilloscope) 
+ * 
+ * @section author Author
+ * - Created by Nitin Nair for EmotiBit.
+ * 
+ */
+
+
+// ToDO: fix for Feather ESP32. Looks like the double buffer implementation is crashing for ESP32.
 //#define DEBUG_SERIAL
 #ifdef ARDUINO_FEATHER_ESP32
 #define PIN_IN_1 5
@@ -23,6 +42,8 @@ void IRAM_ATTR isr_pin1() {
   us_timeBuffer_IN1.push_back(micros());
   ms_timeBuffer_IN1.push_back(millis());
   digitalWrite(PIN_OUT_1, !digitalRead(PIN_OUT_1));  // toggle a pin everytime we get a rising edge. Half the freq of PIN_IN_1
+
+  // ToDo: implement logic for pin 2
 }
 #elif defined ADAFRUIT_FEATHER_M0
 void isr_pin1() {
@@ -64,6 +85,7 @@ void getData(DoubleBufferFloat *buf_us, DoubleBufferFloat *buf_ms, String pin)
     #endif
     for (uint8_t i = 0; i < dataAvailableuS; i++) 
     {
+      // ToDo: improve serial output pattern.
       String str = pin + ":" + String(ms_timeData[i]) + ":" + String(us_timeData[i])  ;
       Serial.println(str); 
     }
@@ -73,7 +95,6 @@ void getData(DoubleBufferFloat *buf_us, DoubleBufferFloat *buf_ms, String pin)
     Serial.print("dataAvailableuS: "); Serial.println(dataAvailableuS);
     Serial.print("dataAvailablemS: "); Serial.println(dataAvailablemS);
     Serial.println("mismatch in buffer lengths");
-    //while(1);
   }
 }
 void setup() {
diff --git a/testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino b/testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino
index 968d634c..7d32d972 100644
--- a/testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino
+++ b/testing/InterruptBasedGpioToggle/InterruptBasedGpioToggle.ino
@@ -1,4 +1,20 @@
-// Code to create a sq waveform to test timing accuracy
+/**
+ * @file InterruptBasedGpioToggle
+ *
+ * @section description Description
+ * This example toggles a GPIO using hw timer.
+ * Creates a sq waveform to test timing accuracy.
+ * This example was created to test the GpioInterruptLogger example.
+ *
+ * @section circuit Circuit
+ * - This is written for ESP32. Tested on Adafruit Feather ESP32 Huzzah.
+ * - Pin 5 generates the timer output. Refer Adafruit Pinout for pin location and details: https://learn.adafruit.com/assets/111179
+ * 
+ * @section author Author
+ * - Created by Nitin Nair for EmotiBit.
+ * 
+ */
+ 
 #define OUT_PIN 5
 hw_timer_t *My_timer = NULL;
 void IRAM_ATTR onTimer(){
@@ -8,7 +24,7 @@ void setup() {
 pinMode(OUT_PIN, OUTPUT);
 My_timer = timerBegin(0, 80, true);
 timerAttachInterrupt(My_timer, &onTimer, true);
-// We want to create a wave with a time period of 6666uS (150Hz)
+// We want to create a wave with a time period of 6666uS (150Hz, default data acuisition task frequency)
 // Choose timer to be 1/2 of required time period
 timerAlarmWrite(My_timer, 3333, true); 
 timerAlarmEnable(My_timer); //Just Enable

From 45435a48cd6ac1bd417aa37fe1e2dfb36f9f13f4 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Wed, 20 Mar 2024 22:47:21 -0400
Subject: [PATCH 13/15] Added minor changes to comments. deleted old code

---
 EmotiBit.cpp                                  | 93 +++++++------------
 EmotiBit.h                                    |  5 +-
 .../EmotiBit_stock_firmware.ino               | 10 +-
 3 files changed, 39 insertions(+), 69 deletions(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index efb8e7ba..4d50c5ee 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -8,7 +8,7 @@ void(*onInterruptCallback)(void);
 #ifdef ARDUINO_FEATHER_ESP32
 TaskHandle_t EmotiBitDataAcquisition;
 hw_timer_t * timer = NULL;
-SemaphoreHandle_t _xMutex;
+SemaphoreHandle_t _xMutex; ///< Semaphore to prevent concurrent access of double buffer between acquisition and update tasks 
 #endif
 
 EmotiBit::EmotiBit() 
@@ -1098,21 +1098,8 @@ uint8_t EmotiBit::setup(String firmwareVariant)
 		//Serial.println("Starting interrupts");
 		startTimer(BASE_SAMPLING_FREQ);
 #elif defined ARDUINO_FEATHER_ESP32
-		// ToDo: remove timer setup once 2 core functionality is verified.
-		// setup timer
-		//timer = timerBegin(0, 80, true); // timer ticks with APB timer, which runs at 80MHz. This setting makes the timer tick every 1uS
-
-		// Attach onTimer function to our timer.
-		//timerAttachInterrupt(timer, &onTimer, true);
-
-		// Set alarm to call onTimer function (value in microseconds).
-		// Repeat the alarm (third parameter)
-		//timerAlarmWrite(timer, 1000000 / BASE_SAMPLING_FREQ, true);
-
-		// Start an alarm
-		//timerAlarmEnable(timer);
 		_xMutex = xSemaphoreCreateMutex();
-		attachToCore(&ReadSensors, this);
+		attachReadSensorsToCore(&ReadSensors, this);
 		attachUpdateToCore(&Update);
 #endif
 	}
@@ -1674,7 +1661,7 @@ uint8_t EmotiBit::update()
 	if (millis() - dataSendTimer > DATA_SEND_INTERVAL)
 	{
 		if (myEmotiBit->DIGITAL_WRITE_DEBUG) digitalWrite(myEmotiBit->DEBUG_OUT_PIN_1, HIGH);
-		_freeToSleep = false;
+		_freeToSleep = false;  // Sending data involves writing to storage. Dont sleep cores when writing to storage.
 		dataSendTimer = millis();
 		
 
@@ -4435,18 +4422,11 @@ void attachToInterruptTC3(void(*readFunction)(void), EmotiBit* e)
 }
 
 #elif defined ARDUINO_FEATHER_ESP32
-// ToDo: remove this once 2 core functionality is verified.
-void onTimer() {
-	vTaskResume(EmotiBitDataAcquisition);
-}
-#endif
-
-#ifdef ARDUINO_FEATHER_ESP32
 
 void attachUpdateToCore(void(*readFunction)(void*))
 {
-	//attachEmotiBit(e);
-	// assigning readSensors to second core
+	// Creating a new task to run emotibit.update()
+	// Task runs on core 0, along with WiFi tasks.
 	xTaskCreatePinnedToCore(
 		*readFunction,   /* Task function. */
 		"EmotiBitDataProcess",     /* name of task. */
@@ -4458,10 +4438,11 @@ void attachUpdateToCore(void(*readFunction)(void*))
 	delay(500);
 }
 
-void attachToCore(void(*readFunction)(void*), EmotiBit*e)
+void attachReadSensorsToCore(void(*readFunction)(void*), EmotiBit*e)
 {
 	attachEmotiBit(e);
-	// assigning readSensors to second core
+	// Creating a new task to run data acquisition
+	// Task runs on core 1, along with main loop.
 	xTaskCreatePinnedToCore(
 		*readFunction,   /* Task function. */
 		"EmotiBitDataAcquisition",     /* name of task. */
@@ -4502,7 +4483,6 @@ void Update(void *pvParameter)
 		{
 			Serial.println("EmotiBit is nullptr");
 		}
-		//vTaskSuspend(NULL);
 		vTaskDelay(pdMS_TO_TICKS(1));  // Delay added to give time to IDLE task
 	}
 }
@@ -4512,8 +4492,7 @@ void ReadSensors(void *pvParameters)
 	Serial.print("The data acquisition is executing on core: "); Serial.println(xPortGetCoreID());
 	int BASE_TIME_PERIOD = (int)((float) 1000000 / (float) BASE_SAMPLING_FREQ);
 	uint32_t timeLast = micros();
-	//uint32_t timeLastProcess_ms = millis(); // if update runs on the same core as acquisition
-	while (1) // the function assigned to the second core should never return
+	while (1) // the function should never return, otherwise causes an exception in RTOS
 	{
 		if(micros() - timeLast > BASE_TIME_PERIOD)
 		{
@@ -4530,42 +4509,32 @@ void ReadSensors(void *pvParameters)
 			{
 				Serial.println("EmotiBit is nullptr");
 			}
-			//vTaskSuspend(NULL);
-			// if(millis() - timeLastProcess_ms > 50)
-			// {
-			// 	// every 50mS, run the process task
-				
-			// 	timeLastProcess_ms = millis();
-			// 	vTaskDelay(pdMS_TO_TICKS(1));// give update some time
-				
-			// }
-			// else
-			// {
-				if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
+
+			if(myEmotiBit->_freeToSleep && myEmotiBit->_emotiBitWiFi._wifiOff)
+			{
+				int sleepTime;
+				// ToDo: get more accurate buffer time
+				uint32_t wakeupTimebuffer = 600; // in uS. Empirically derived estimate. Time taken by CPU to wake up
+				// ToDo: move this into a calculateSleepTime() function
+				if((timeLast + BASE_TIME_PERIOD) - micros() > wakeupTimebuffer) 
 				{
-					int sleepTime;
-					// ToDo: get more accurate buffer time
-					uint32_t wakeupTimebuffer = 600; // Empirically derived estimate. Time taken by CPU to wake up
-					// ToDo: move this into a calculateSleepTime() function
-					if((timeLast + BASE_TIME_PERIOD) - micros() > wakeupTimebuffer) // calculate time to sleep
-					{
-						sleepTime = (int)(timeLast + BASE_TIME_PERIOD) - (int)micros() - (int)wakeupTimebuffer;
-					} 
+					// calculate time to sleep
+					sleepTime = (int)(timeLast + BASE_TIME_PERIOD) - (int)micros() - (int)wakeupTimebuffer;
+				} 
 
-					if(sleepTime > wakeupTimebuffer)
-					{
-						// only sleep if we can wake up in time
-						esp_sleep_enable_timer_wakeup(sleepTime); // every 6.6mS to maintain 150Hz sampling
-						esp_light_sleep_start(); // start light sleep
-					}
-				}
-				else
+				if(sleepTime > wakeupTimebuffer)
 				{
-					// ToDo: Schedule time give to idle task. Check min time before watchdog timer is activated.
-					vTaskDelay(pdMS_TO_TICKS(1));  // if not sleeping, give time to IDLE task
+					// only sleep if we can wake up in time
+					esp_sleep_enable_timer_wakeup(sleepTime); // every 6.6mS to maintain 150Hz base sampling
+					esp_light_sleep_start(); // start light sleep
 				}
-			//}
-			//vTaskDelay(pdMS_TO_TICKS(1));
+			}
+			else
+			{
+				// ToDo: Schedule time give to idle task.
+				vTaskDelay(pdMS_TO_TICKS(1));  // if not sleeping, give time-slice to IDLE task
+			}
+
 		}
 		
 	}
diff --git a/EmotiBit.h b/EmotiBit.h
index c992ee60..3d4ee23e 100644
--- a/EmotiBit.h
+++ b/EmotiBit.h
@@ -50,7 +50,7 @@ class EmotiBit {
 
 
   // 1.9.0.feat-2Core.1 - update and acquisition on core 1. WiFi on core 0
-  String firmware_version = "1.9.0.feat-2Core.3";
+  String firmware_version = "1.9.0.feat-2Core.4";
 
 
 
@@ -684,8 +684,7 @@ void attachEmotiBit(EmotiBit*e = nullptr);
 void attachToInterruptTC3(void(*readFunction)(void), EmotiBit*e = nullptr);
 void ReadSensors();
 #elif defined ARDUINO_FEATHER_ESP32
-void onTimer();
-void attachToCore(void(*readFunction)(void*), EmotiBit*e = nullptr);
+void attachReadSensorsToCore(void(*readFunction)(void*), EmotiBit*e = nullptr);
 void ReadSensors(void* pvParameters);
 void Update(void* pvParameters);
 void attachUpdateToCore(void(*readFunction)(void*));
diff --git a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
index 30ec7f6f..09dbe51b 100644
--- a/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
+++ b/EmotiBit_stock_firmware/EmotiBit_stock_firmware.ino
@@ -51,11 +51,13 @@ void setup()
 
 void loop()
 {
-	//Serial.println("emotibit.update()");
-	//emotibit.update();
+	// Main loop is attached to a different task spawned by default. In our current scheme, 
+	// main loop runs run when acquisitoin task pasuses by calling vTaskDelay()
 	
-	// gets run when acquisitoin gives a delay
-	// ToDo: assess time slice given to this task once ported to 2-core topology
+	// The update function has been moved to its separate task.
+	//emotibit.update(); 
+	
+	// ToDo: assess time slice given to this task once ported to 2-core 2-task architecture
 	size_t dataAvailable = emotibit.readData(EmotiBit::DataType::PPG_GREEN, &data[0], dataSize);
 	if (dataAvailable > 0)
 	{

From 41688f3dfaaa8423c79c6b4f90aaacd44fa2e1b5 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Wed, 20 Mar 2024 22:51:26 -0400
Subject: [PATCH 14/15] removed unused code

---
 EmotiBit.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/EmotiBit.cpp b/EmotiBit.cpp
index 4d50c5ee..5bdacb78 100644
--- a/EmotiBit.cpp
+++ b/EmotiBit.cpp
@@ -7,7 +7,6 @@ EmotiBit* myEmotiBit = nullptr;
 void(*onInterruptCallback)(void);
 #ifdef ARDUINO_FEATHER_ESP32
 TaskHandle_t EmotiBitDataAcquisition;
-hw_timer_t * timer = NULL;
 SemaphoreHandle_t _xMutex; ///< Semaphore to prevent concurrent access of double buffer between acquisition and update tasks 
 #endif
 

From edb773829b20a27db24699b61187308924741793 Mon Sep 17 00:00:00 2001
From: Nitin Nair <nitin7nair@gmail.com>
Date: Wed, 20 Mar 2024 22:53:09 -0400
Subject: [PATCH 15/15] minor changes to comments.

---
 EmotiBit.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/EmotiBit.h b/EmotiBit.h
index 3d4ee23e..ace6832b 100644
--- a/EmotiBit.h
+++ b/EmotiBit.h
@@ -49,7 +49,7 @@ class EmotiBit {
 	};
 
 
-  // 1.9.0.feat-2Core.1 - update and acquisition on core 1. WiFi on core 0
+
   String firmware_version = "1.9.0.feat-2Core.4";