From c711252791018d7818e4e717da1e2312ee94928d Mon Sep 17 00:00:00 2001
From: Matthew Kennedy <makenne@microsoft.com>
Date: Thu, 10 Dec 2020 22:08:00 -0800
Subject: [PATCH] detect sensor overheat

---
 firmware/fault.h            |  1 +
 firmware/heater_control.cpp | 11 ++++++++---
 firmware/wideband_config.h  |  6 ++++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/firmware/fault.h b/firmware/fault.h
index f5ae19e..7b4967a 100644
--- a/firmware/fault.h
+++ b/firmware/fault.h
@@ -6,6 +6,7 @@ enum class Fault
 
     // First fault code at 3 so it's easier to see
     SensorDidntHeat = 3,
+    SensorOverheat = 4,
 };
 
 void setFault(Fault fault);
diff --git a/firmware/heater_control.cpp b/firmware/heater_control.cpp
index 2d17bb9..6275603 100644
--- a/firmware/heater_control.cpp
+++ b/firmware/heater_control.cpp
@@ -20,7 +20,7 @@ enum class HeaterState
     Stopped,
 };
 
-int timeCounter = 5000 / 50;
+int timeCounter = HEATER_PREHEAT_TIME / HEATER_CONTROL_PERIOD;
 float rampDuty = 0.5f;
 
 static HeaterState GetNextState(HeaterState state, float sensorEsr)
@@ -37,7 +37,7 @@ static HeaterState GetNextState(HeaterState state, float sensorEsr)
                 rampDuty = 0.5f;
 
                 // Next phase times out at 15 seconds
-                timeCounter = 15000 / 50;
+                timeCounter = HEATER_WARMUP_TIMEOUT / HEATER_CONTROL_PERIOD;
 
                 return HeaterState::WarmupRamp;
             }
@@ -45,7 +45,7 @@ static HeaterState GetNextState(HeaterState state, float sensorEsr)
             // Stay in preheat - wait for time to elapse
             break;
         case HeaterState::WarmupRamp:
-            if (sensorEsr < 1000)
+            if (sensorEsr < HEATER_CLOSED_LOOP_THRESHOLD_ESR)
             {
                 return HeaterState::ClosedLoop;
             }
@@ -60,6 +60,11 @@ static HeaterState GetNextState(HeaterState state, float sensorEsr)
             break;
         case HeaterState::ClosedLoop:
             // TODO: handle departure from closed loop
+            if (sensorEsr < HEATER_FAULT_ESR)
+            {
+                setFault(Fault::SensorOverheat);
+            }
+
             break;
         case HeaterState::Stopped: break;
     }
diff --git a/firmware/wideband_config.h b/firmware/wideband_config.h
index fc1d974..80b1b73 100644
--- a/firmware/wideband_config.h
+++ b/firmware/wideband_config.h
@@ -32,4 +32,10 @@
 //    Heater controller config
 // *******************************
 #define HEATER_CONTROL_PERIOD 50
+
+#define HEATER_PREHEAT_TIME 5000
+#define HEATER_WARMUP_TIMEOUT 15000
+
+#define HEATER_CLOSED_LOOP_THRESHOLD_ESR 1000
 #define HEATER_TARGET_ESR 300
+#define HEATER_FAULT_ESR 200