diff --git a/firmware/controllers/math/engine_math.h b/firmware/controllers/math/engine_math.h
index 3bdd15d2bb..7301dcff71 100644
--- a/firmware/controllers/math/engine_math.h
+++ b/firmware/controllers/math/engine_math.h
@@ -90,6 +90,9 @@ void setTimingLoadBin(float from, float to DECLARE_ENGINE_PARAMETER_SUFFIX);
 
 void setSingleCoilDwell(engine_configuration_s *engineConfiguration);
 
+// we combine trigger-defined triggerShape.tdcPosition with user-defined CONFIG(globalTriggerAngleOffset)
+// expectation is that for well-known triggers CONFIG(globalTriggerAngleOffset) would usually be zero
+// while for toothed wheels user would have to provide a value
 #define tdcPosition() \
 		(ENGINE(triggerCentral.triggerShape.tdcPosition) + CONFIG(globalTriggerAngleOffset))