diff --git a/firmware/controllers/trigger/main_trigger_callback.cpp b/firmware/controllers/trigger/main_trigger_callback.cpp
index 025a12e81d..8ef816d734 100644
--- a/firmware/controllers/trigger/main_trigger_callback.cpp
+++ b/firmware/controllers/trigger/main_trigger_callback.cpp
@@ -43,6 +43,7 @@
 #include "histogram.h"
 #include "fuel_math.h"
 #include "histogram.h"
+#include "cdm_ion_sense.h"
 #include "engine_controller.h"
 #include "efi_gpio.h"
 #if EFI_PROD_CODE
@@ -448,6 +449,13 @@ void mainTriggerCallback(trigger_event_e ckpSignalType, uint32_t trgEventIndex D
 	}
 	efiAssertVoid(CUSTOM_STACK_6629, getCurrentRemainingStack() > 128, "lowstck#2");
 
+#if EFI_CDM_INTEGRATION
+	if (trgEventIndex == 0 && CONFIGB(cdmInputPin) != GPIO_UNASSIGNED) {
+		int cdmKnockValue = getCurrentCdmValue(engine->triggerCentral.triggerState.getTotalRevolutionCounter());
+		engine->knockLogic(cdmKnockValue);
+	}
+#endif /* EFI_CDM_INTEGRATION */
+
 	if (trgEventIndex >= ENGINE(engineCycleEventCount)) {
 		/**
 		 * this could happen in case of a trigger error, just exit silently since the trigger error is supposed to be handled already
diff --git a/firmware/hw_layer/cdm_ion_sense.cpp b/firmware/hw_layer/cdm_ion_sense.cpp
index 781f2e02e1..65277d210f 100644
--- a/firmware/hw_layer/cdm_ion_sense.cpp
+++ b/firmware/hw_layer/cdm_ion_sense.cpp
@@ -13,22 +13,36 @@
 #include "engine.h"
 
 CdmState::CdmState() {
-	currentRevolution = 0;
+	accumilatingAtRevolution = 0;
 	currentValue = 0;
-	accumulator = 0;
+	accumulatingCurrentValue = 0;
 }
 
-int CdmState::getValue() {
-	return currentValue;
+int CdmState::getValue(int currentRevolution) {
+	applyAccumulatedData(currentRevolution);
+	if (currentRevolution == currentValueAtIndex + 1) {
+		// returning total result of previous engine cycle
+		return currentValue;
+	}
+	// we are here if previous engine cycle had no knock events
+	return 0;
+}
+
+void CdmState::applyAccumulatedData(int currentRevolution) {
+	if (currentRevolution > accumilatingAtRevolution) {
+		currentValue = accumulatingCurrentValue;
+		currentValueAtIndex = accumilatingAtRevolution;
+	}
 }
 
 void CdmState::onNewSignal(int currentRevolution) {
-	if (this->currentRevolution == currentRevolution) {
-		accumulator++;
+	if (this->accumilatingAtRevolution == currentRevolution) {
+		accumulatingCurrentValue++;
 	} else {
-		this->currentRevolution = currentRevolution;
-		currentValue = accumulator;
-		accumulator = 1;
+		applyAccumulatedData(currentRevolution);
+		// start new accumulation
+		accumilatingAtRevolution = currentRevolution;
+		accumulatingCurrentValue = 1;
 	}
 }
 
@@ -41,6 +55,10 @@ EXTERN_ENGINE;
 
 static CdmState instance;
 
+int getCurrentCdmValue(int currentRevolution) {
+	return instance.getValue(currentRevolution);
+}
+
 #if EFI_TUNER_STUDIO
 void ionPostState(TunerStudioOutputChannels *tsOutputChannels) {
 	tsOutputChannels->debugIntField1 = instance.totalCdmEvents;
@@ -56,8 +74,7 @@ static void extIonCallback(void *arg) {
 }
 
 void cdmIonInit(void) {
-	// todo: allow 'GPIOA_0' once we migrate to new mandatory configuration
-	if (CONFIGB(cdmInputPin) == GPIOA_0 || CONFIGB(cdmInputPin) == GPIO_UNASSIGNED) {
+	if (CONFIGB(cdmInputPin) == GPIO_UNASSIGNED) {
 		return;
 	}
 	int pin = (int)CONFIGB(cdmInputPin);
diff --git a/firmware/hw_layer/cdm_ion_sense.h b/firmware/hw_layer/cdm_ion_sense.h
index 2bc9dd90ed..444f55aa96 100644
--- a/firmware/hw_layer/cdm_ion_sense.h
+++ b/firmware/hw_layer/cdm_ion_sense.h
@@ -1,7 +1,7 @@
 /*
- * cdm_ion_sense.h
+ * @file cdm_ion_sense.h
  *
- *  Created on: Dec 31, 2018
+ * @date Dec 31, 2018
  * @author Andrey Belomutskiy, (c) 2012-2019
  */
 
@@ -13,18 +13,21 @@
 class CdmState {
 public:
 	CdmState();
-	int currentRevolution;
+	int totalCdmEvents = 0;
+
+	int accumilatingAtRevolution = -1;
 	/**
 	 * accumulated value for engine cycle which is not over yet
 	 */
-	int accumulator;
-	int totalCdmEvents = 0;
+	int accumulatingCurrentValue;
 	/**
 	 * event counter for previous complete engine cycle
 	 */
-	int currentValue;
+	int currentValue = 0;
+	int currentValueAtIndex = -1;
 	void onNewSignal(int currentRevolution);
-	int getValue();
+	void applyAccumulatedData(int currentRevolution);
+	int getValue(int currentRevolution);
 };
 
 #if EFI_TUNER_STUDIO
@@ -33,5 +36,6 @@ void ionPostState(TunerStudioOutputChannels *tsOutputChannels);
 #endif
 
 void cdmIonInit(void);
+int getCurrentCdmValue(int currentRevolution);
 
 #endif /* HW_LAYER_CDM_ION_SENSE_H_ */
diff --git a/unit_tests/tests/test_ion.cpp b/unit_tests/tests/test_ion.cpp
index 9858f199a2..4aec1141bf 100644
--- a/unit_tests/tests/test_ion.cpp
+++ b/unit_tests/tests/test_ion.cpp
@@ -14,18 +14,27 @@
 TEST(ion, signalCounter) {
 	CdmState state;
 
-	EXPECT_EQ(0, state.getValue());
+	EXPECT_EQ(0, state.getValue(0));
 
 	state.onNewSignal(2);
 	state.onNewSignal(2);
 	state.onNewSignal(2);
 
 	// value is still '0' until we signal end of engine cycle
-	EXPECT_EQ(0, state.getValue());
+	EXPECT_EQ(0, state.getValue(2));
+
+	// this invocation would flush current accumulation
+	EXPECT_EQ(3, state.getValue(3));
+
+	state.onNewSignal(3);
+	// returning previous full cycle value
+	EXPECT_EQ(3, state.getValue(3));
+
+
+	EXPECT_EQ(1, state.getValue(4));
+	EXPECT_EQ(0, state.getValue(5));
+
 
-	// this signals start of new cycle
-	state.onNewSignal(4);
-	EXPECT_EQ(3, state.getValue());
 
 
 }