From a90d13b038b92a827b782929e2b784bdf461fd0a Mon Sep 17 00:00:00 2001
From: Josh Stewart <josh@noisymime.org>
Date: Mon, 27 Jun 2016 10:31:52 +1000
Subject: [PATCH] Improved flex error checking

---
 comms.ino               |  3 ++-
 reference/speeduino.ini |  2 +-
 timers.ino              | 20 ++++++++++++++++++--
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/comms.ino b/comms.ino
index 23a7d2e5..d3d0e368 100644
--- a/comms.ino
+++ b/comms.ino
@@ -262,7 +262,8 @@ void sendValues(int length)
   response[31] = lowByte(currentStatus.rpmDOT);
   response[32] = highByte(currentStatus.rpmDOT);
 
-  response[33] = currentStatus.flex;
+  response[33] = currentStatus.flex; //Flex sensor value (or 0 if not used)
+  
 cli();
   Serial.write(response, (size_t)packetSize);
 sei();
diff --git a/reference/speeduino.ini b/reference/speeduino.ini
index fde69ba0..cd5cecd9 100644
--- a/reference/speeduino.ini
+++ b/reference/speeduino.ini
@@ -465,7 +465,7 @@ page = 8
     requiresPowerCycle = launchPin
     requiresPowerCycle = launchEnable
     requiresPowerCycle = launchHiLo
-;    requiresPowerCycle = flexEnabled
+    requiresPowerCycle = flexEnabled
     
     defaultValue = pinLayout, 1
     defaultValue = TrigPattern, 0
diff --git a/timers.ino b/timers.ino
index 00fa8dd2..424fa609 100644
--- a/timers.ino
+++ b/timers.ino
@@ -99,9 +99,25 @@ void timer2Overflowinterrupt() //Most ARM chips can simply call a function
     //Set the flex reading (if enabled). The flexCounter is updated with every pulse from the sensor. If cleared once per second, we get a frequency reading
     if(configPage1.flexEnabled)
     {
-      if(flexCounter > 150 || flexCounter < 50)
+      if(flexCounter < 50)
       {
-        //This indicated an error condition. Spec of the sensor is that errors are above 170Hz)
+        currentStatus.flex = 0; //Standard GM Continental sensor reads from 50Hz (0 ethanol) to 150Hz (Pure ethanol). Subtracting 50 from the frequency therefore gives the ethanol percentage.
+        flexCounter = 0;
+      }
+      else if (flexCounter > 151) //1 pulse buffer
+      {
+        
+        if(flexCounter < 169)
+        {
+          currentStatus.flex = 100; //Standard GM Continental sensor reads from 50Hz (0 ethanol) to 150Hz (Pure ethanol). Subtracting 50 from the frequency therefore gives the ethanol percentage.
+          flexCounter = 0;
+        }
+        else
+        {
+          //This indicates an error condition. Spec of the sensor is that errors are above 170Hz)
+          currentStatus.flex = 0;
+          flexCounter = 0;
+        }
       }
       else
       {