From 779ad8ce350d8404ad0dac1f8be9f7efe164f092 Mon Sep 17 00:00:00 2001
From: Gonzalo <gonzalonalbandian@hotmail.com>
Date: Tue, 18 May 2021 18:25:13 -0300
Subject: [PATCH 1/2] Changed return value for the current tunning stage

Please, check example suggested in the other PR.
---
 src/QuickPID.cpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/QuickPID.cpp b/src/QuickPID.cpp
index 2dd5257..b675257 100644
--- a/src/QuickPID.cpp
+++ b/src/QuickPID.cpp
@@ -367,10 +367,18 @@ byte AutoTunePID::autoTuneLoop()
     case NEW_TUNINGS: // ready to apply tunings
       *_output = 0;
       _autoTuneStage++;
-      return NEW_TUNINGS;
+      //return NEW_TUNINGS;
       break;
+        
+    case RUN_PID: // ready to apply tunings
+      return RUN_PID;
+     break;
   }
-  return RUN_PID;
+   
+  if(_autoTuneStage < 1) // safety measure to avoid overflow of _autoTuneStage variable if its value is 0, which shouldn't happen never. Nonetheless...
+     return 0
+  else
+     return _autoTuneStage - 1;
 }
 
 void AutoTunePID::setAutoTuneConstants(float* kp, float* ki, float* kd)

From d7e4e31acf79351ac4b1e22b90cdf9d5e117ef0e Mon Sep 17 00:00:00 2001
From: Gonzalo <gonzalonalbandian@hotmail.com>
Date: Tue, 18 May 2021 18:27:17 -0300
Subject: [PATCH 2/2] Please consider this aproach

Just some safety deference checks and better segmentation of the code. Just to better understand what is running at each loop cycle.
---
 .../AutoTune_Filter_DIRECT.ino                | 54 +++++++++++--------
 1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/examples/AutoTune_Filter_DIRECT/AutoTune_Filter_DIRECT.ino b/examples/AutoTune_Filter_DIRECT/AutoTune_Filter_DIRECT.ino
index f5ebde7..04cbcb9 100644
--- a/examples/AutoTune_Filter_DIRECT/AutoTune_Filter_DIRECT.ino
+++ b/examples/AutoTune_Filter_DIRECT/AutoTune_Filter_DIRECT.ino
@@ -39,30 +39,40 @@ void setup() {
 
 void loop() {
 
-  if (_myPID.autoTune->autoTuneLoop() != _myPID.autoTune->RUN_PID) { // running autotune
-
-    Input = avg(_myPID.analogReadFast(inputPin)); // filtered input
-    analogWrite(outputPin, Output);
-  }
-
-  if (_myPID.autoTune->autoTuneLoop() == _myPID.autoTune->NEW_TUNINGS) { // get new tunings
-    _myPID.autoTune->setAutoTuneConstants(&Kp, &Ki, &Kd); // set new tunings
-    _myPID.clearAutoTune(); // releases memory used by AutoTune object
-    _myPID.SetMode(QuickPID::AUTOMATIC); // setup PID
-    _myPID.SetTunings(Kp, Ki, Kd, POn); // apply new tunings to PID
-    Setpoint = 500;
-  }
-
-  if (_myPID.autoTune->autoTuneLoop() == _myPID.autoTune->RUN_PID) { // running PID
-    if (printOrPlotter == 0) { // plotter
-      Serial.print("Setpoint:");  Serial.print(Setpoint);  Serial.print(",");
-      Serial.print("Input:");     Serial.print(Input);     Serial.print(",");
-      Serial.print("Output:");    Serial.print(Output);    Serial.println();
-    }
-    Input = _myPID.analogReadFast(inputPin);
+if (_myPID.autoTune) // Avoid deferencing nullptr after _myPID.clearAutoTune()
+{	
+	uint8_t autoTuningCurrentStage = autoTuneLoop();
+	if(autoTuningCurrentStage < _myPID.autoTune->RUN_PID)
+	{
+		Input = avg(_myPID.analogReadFast(inputPin)); // filtered input
+		analogWrite(outputPin, Output);
+		
+		if (autoTuningCurrentStage == _myPID.autoTune->NEW_TUNINGS) // get new tunings
+		{
+			_myPID.autoTune->setAutoTuneConstants(&Kp, &Ki, &Kd); // set new tunings
+			_myPID.SetMode(QuickPID::AUTOMATIC); // setup PID
+			_myPID.SetTunings(Kp, Ki, Kd, POn); // apply new tunings to PID
+			Setpoint = 500;
+		}
+	}
+	else // RUN_PID stage
+	{
+		if (printOrPlotter == 0) // plotter
+		{
+			_myPID.clearAutoTune(); // releases memory used by AutoTune object
+			Serial.print("Setpoint:");  Serial.print(Setpoint);  Serial.print(",");
+			Serial.print("Input:");     Serial.print(Input);     Serial.print(",");
+			Serial.print("Output:");    Serial.print(Output);    Serial.println();
+       }
+	}
+	
+}
+else // Autotune already done (or not created)
+{
+	Input = _myPID.analogReadFast(inputPin);
     _myPID.Compute();
     analogWrite(outputPin, Output);
-  }
+}
 }
 
 float avg(int inputVal) {