Index: firmware/App/Controllers/BloodFlow.c
===================================================================
diff -u -r6fcdec8a308be986e5a64b4222918e718622a19d -r794f0aea88a5a860448e54e99db6e2e881b22900
--- firmware/App/Controllers/BloodFlow.c	(.../BloodFlow.c)	(revision 6fcdec8a308be986e5a64b4222918e718622a19d)
+++ firmware/App/Controllers/BloodFlow.c	(.../BloodFlow.c)	(revision 794f0aea88a5a860448e54e99db6e2e881b22900)
@@ -110,27 +110,39 @@
 #define FLOW_SIG_STRGTH_ALARM_PERSIST       ( 5 * MS_PER_SECOND )
 #define MIN_FLOW_SIG_STRENGTH               0.9             ///< Minimum flow sensor signal strength (90%).
 
+/// Blood flow read timeout alarm persistence.
+#define BLOOD_FLOW_READ_TIMEOUT_PERSIST     ( MS_PER_SECOND )
+
 #define BFM_SENSOR_PARAM_CORRUPT_STATUS     0x7             ///< Blood flow meter NVM parameter status.
 
 /// Enumeration of blood pump controller states.
 typedef enum BloodPump_States
 {
-    BLOOD_PUMP_OFF_STATE = 0,                   ///< Blood pump off state.
-    BLOOD_PUMP_RAMPING_UP_STATE,                ///< Blood pump ramping up state.
-    BLOOD_PUMP_RAMPING_DOWN_STATE,              ///< Blood pump ramping down state.
-    BLOOD_PUMP_CONTROL_TO_TARGET_STATE,         ///< Blood pump controlling to target state.
-    NUM_OF_BLOOD_PUMP_STATES                    ///< Number of blood pump states.
+    BLOOD_PUMP_OFF_STATE = 0,                   ///< Blood pump off state
+    BLOOD_PUMP_RAMPING_UP_STATE,                ///< Blood pump ramping up state
+    BLOOD_PUMP_RAMPING_DOWN_STATE,              ///< Blood pump ramping down state
+    BLOOD_PUMP_CONTROL_TO_TARGET_STATE,         ///< Blood pump controlling to target state
+    NUM_OF_BLOOD_PUMP_STATES                    ///< Number of blood pump states
 } BLOOD_PUMP_STATE_T;
 
 /// Enumeration of blood pump self-test states.
 typedef enum BloodFlow_Self_Test_States
 {
-    BLOOD_FLOW_SELF_TEST_STATE_START = 0,       ///< Blood pump self-test start state.
-    BLOOD_FLOW_TEST_STATE_IN_PROGRESS,          ///< Blood pump self-test in progress state.
-    BLOOD_FLOW_TEST_STATE_COMPLETE,             ///< Blood pump self-test completed state.
-    NUM_OF_BLOOD_FLOW_SELF_TEST_STATES          ///< Number of blood pump self-test states.
+    BLOOD_FLOW_SELF_TEST_STATE_START = 0,       ///< Blood pump self-test start state
+    BLOOD_FLOW_TEST_STATE_IN_PROGRESS,          ///< Blood pump self-test in progress state
+    BLOOD_FLOW_TEST_STATE_COMPLETE,             ///< Blood pump self-test completed state
+    NUM_OF_BLOOD_FLOW_SELF_TEST_STATES          ///< Number of blood pump self-test states
 } BLOOD_FLOW_SELF_TEST_STATE_T;
 
+/// Enumeration of blood flow read counters.
+typedef enum BloodFlow_Read_Counters
+{
+    BLOOD_FLOW_READ_CTR_FAST_PACKET = 0,        ///< Blood flow fast packet read counter
+    BLOOD_FLOW_READ_CTR_SLOW_PACKET,            ///< Blood flow slow packet read counter
+    BLOOD_FLOW_READ_CTR_STATUS_PACKET,          ///< Blood flow status packet read counter
+    NUM_OF_BLOOD_FLOW_READ_COUNTERS             ///< Number of blood pump read counters.
+} BLOOD_FLOW_READ_COUNTER_T;
+
 // Pin assignments for pump stop and direction outputs
 #define STOP_CAN3_PORT_MASK             0x00000002  // (Tx - re-purposed as output GPIO for blood pump stop signal)
 #define DIR_CAN3_PORT_MASK              0x00000002  // (Rx - re-purposed as output GPIO for blood pump direction signal)
@@ -188,7 +200,11 @@
 static F32 flowReadingsTotal = 0.0;                                             ///< Rolling total - used to calc average
 static U32 flowReadingsCount = 0;                                               ///< Number of samples in flow rolling average buffer
 
-static U32 bpCurrErrorDurationCtr = 0;                                          ///< Used for tracking persistence of bp current errors
+static U32 bpCurrErrorDurationCtr = 0;                                          ///< Used for tracking persistence of bp current errors
+
+static U08 lastBloodFlowFastPacketReadCtr = 0;                                  ///< Previous read counter for the blood flow fast packets
+static U08 lastBloodFlowSlowPacketReadCtr = 0;                                  ///< Previous read counter for the blood flow slow packets
+static U08 lastBloodFlowStatusPacketReadCtr = 0;                                ///< Previous read counter for the blood flow status packets
 
 // ********** private function prototypes **********
 
@@ -243,6 +259,7 @@
 
     // Initialize persistent alarm for flow sensor signal strength too low
     initPersistentAlarm( ALARM_ID_BLOOD_FLOW_SIGNAL_STRENGTH_TOO_LOW, FLOW_SIG_STRGTH_ALARM_PERSIST, FLOW_SIG_STRGTH_ALARM_PERSIST );
+    initPersistentAlarm( ALARM_ID_HD_BP_FLOW_READ_TIMEOUT_ERROR, 0, BLOOD_FLOW_READ_TIMEOUT_PERSIST );
 }
 
 /*********************************************************************//**
@@ -430,13 +447,35 @@
     HD_OP_MODE_T opMode = getCurrentOperationMode();
     U16 bpRPM = getIntADCReading( INT_ADC_BLOOD_PUMP_SPEED );
     U16 bpmA = getIntADCReading( INT_ADC_BLOOD_PUMP_MOTOR_CURRENT );
-
 #ifndef V1_5_SYSTEM
     F32 bpFlow = ( getFPGABloodFlow() * bloodFlowCalGain ) + bloodFlowCalOffset;
 #else
-    F32 bpFlow = ( ( getFPGABloodFlow() * -1.0 ) * bloodFlowCalGain ) + bloodFlowCalOffset;  // Blood flow sensor installed backwards on HD
+    F32 bpFlow = ( ( getFPGABloodFlow() * -1.0 ) * bloodFlowCalGain ) + bloodFlowCalOffset;  // Blood flow sensor installed backwards on HD
 #endif
-
+    U08 fpReadCtr = getFPGABloodFlowFastPacketReadCounter();
+    U08 spReadCtr = getFPGABloodFlowSlowPacketReadCounter();
+    U08 stpReadCtr = getFPGABloodFlowStatusPacketReadCounter();
+    U08 flowErrorCtr = getFPGABloodFlowErrorCounter();
+
+    // Check for stale flow reading
+    if ( TRUE == isPersistentAlarmTriggered( ALARM_ID_HD_BP_FLOW_READ_TIMEOUT_ERROR, ( fpReadCtr == lastBloodFlowFastPacketReadCtr ) ) )
+    {
+        SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_BP_FLOW_READ_TIMEOUT_ERROR, (U32)BLOOD_FLOW_READ_CTR_FAST_PACKET )
+    }
+    if ( TRUE == isPersistentAlarmTriggered( ALARM_ID_HD_BP_FLOW_READ_TIMEOUT_ERROR, ( spReadCtr == lastBloodFlowSlowPacketReadCtr ) ) )
+    {
+        SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_BP_FLOW_READ_TIMEOUT_ERROR, (U32)BLOOD_FLOW_READ_CTR_SLOW_PACKET )
+    }
+    if ( TRUE == isPersistentAlarmTriggered( ALARM_ID_HD_BP_FLOW_READ_TIMEOUT_ERROR, ( stpReadCtr == lastBloodFlowStatusPacketReadCtr ) ) )
+    {
+        SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_BP_FLOW_READ_TIMEOUT_ERROR, (U32)BLOOD_FLOW_READ_CTR_STATUS_PACKET )
+    }
+
+    // Record flow read counters for next time around
+    lastBloodFlowFastPacketReadCtr = fpReadCtr;
+    lastBloodFlowSlowPacketReadCtr = spReadCtr;
+    lastBloodFlowStatusPacketReadCtr = stpReadCtr;
+
     adcBloodPumpMCSpeedRPM.data = (F32)(SIGN_FROM_12_BIT_VALUE(bpRPM)) * BP_SPEED_ADC_TO_RPM_FACTOR;
     adcBloodPumpMCCurrentmA.data = (F32)(SIGN_FROM_12_BIT_VALUE(bpmA)) * BP_CURRENT_ADC_TO_MA_FACTOR;
     bloodFlowSignalStrength.data = getFPGABloodFlowSignalStrength();
@@ -465,6 +504,7 @@
     // Publish blood flow data on interval
     publishBloodFlowData();
 }
+//ALARM_ID_HD_BP_FLOW_SENSOR_ERROR = 208,                         ///< HD blood flow sensor error
 
 /*********************************************************************//**
  * @brief