Add some comments

firmware/controllers/tcu/gc_generic.cpp

@@ -43,6 +43,8 @@ void GenericGearController::update() {
 		// Loop through inputs
 		for (size_t p = 0; p < efi::size(engineConfiguration->tcu_rangeInput); p++) {
 			float cellState = rangeStates[p];
+			// We allow the user to configure either a digital input or an analog input for each pin,
+			//  so we need to check which is valid.
 			if (isAdcChannelValid(engineConfiguration->tcu_rangeAnalogInput[p])) {
 				float pinState = Sensor::getOrZero(getAnalogSensorType(p));
 				if (isNearest(pinState, p, rangeStates)) {
@@ -96,6 +98,8 @@ void GenericGearController::update() {
 			setDesiredGear(NEUTRAL);
 			break;
 		case SelectedGear::ManualPlus :
+			// Only allow manual shift once per 500 ms,
+			// and if the selected range was Manual prior to this update
 			if (!shiftTimer.hasElapsedMs(500) || lastRange != SelectedGear::Manual) {
 				break;
 			}
@@ -115,6 +119,8 @@ void GenericGearController::update() {
 			}
 			break;
 		case SelectedGear::ManualMinus :
+			// Only allow manual shift once per 500 ms,
+			// and if the selected range was Manual prior to this update
 			if (!shiftTimer.hasElapsedMs(500) || lastRange != SelectedGear::Manual) {
 				break;
 			}
@@ -134,6 +140,8 @@ void GenericGearController::update() {
 			}
 			break;
 		case SelectedGear::Drive :
+			// If the gear selector is in drive, let AutomaticGearController,
+			// which this class inherits from, decide what gear the transmission should be in.
 			AutomaticGearController::update();
 			return;
 		default:

firmware/controllers/tcu/gear_controller.cpp

@@ -29,7 +29,7 @@ void GearControllerBase::update() {
 	if (transmissionController == NULL) {
 		initTransmissionController();
 	} else if (transmissionController->getMode() != engineConfiguration->transmissionControllerMode) {
-		// TODO de-init here
+		// TODO de-init here to allow change without power cycling
 		initTransmissionController();
 	}
 
@@ -75,6 +75,10 @@ void initGearController() {
 }
 
 float* GearControllerBase::getRangeStateArray(int i) {
+	// I don't remember why I put manual +/- first.
+	// I think maybe I had some concern about them needing to override under-specified ranges?
+	// e.g. with it this way, you could put 2 in the cells for +/- pins in everything else.
+	// So this way might make it a little easier/foolproof to configure, but not necessary.
 	switch (i) {
 	case 1 :
 		return config->tcu_rangePlus;

firmware/controllers/tcu/tc_4.cpp

@@ -27,6 +27,7 @@ void Generic4TransmissionController::update(gear_e gear) {
 		measureShiftTime(gear);
 	}
 
+	// set torque converter and pressure control state
 	setTccState(gear);
 	setPcState(gear);
 
@@ -35,6 +36,7 @@ void Generic4TransmissionController::update(gear_e gear) {
 	SimpleTransmissionController::update(gear);
 
 	float time = isShiftCompleted();
+	// 0 means shift is not completed
 	if (time != 0) {
 		lastShiftTime = time;
 		isShifting = false;
@@ -42,6 +44,7 @@ void Generic4TransmissionController::update(gear_e gear) {
 }
 
 void Generic4TransmissionController::setTccState(gear_e gear) {
+	// disable if shifting
 	if (isShifting) {
 		enginePins.tcuTccOnoffSolenoid.setValue(0);
 		return;
@@ -52,10 +55,12 @@ void Generic4TransmissionController::setTccState(gear_e gear) {
 	if (!tps.Valid || !vss.Valid) {
 		return;
 	}
+	// only enable TC in gear 4
 	if (gear == GEAR_4) {
 		int lockSpeed = interpolate2d(tps.Value, config->tcu_tccTpsBins, config->tcu_tccLockSpeed);
 		int unlockSpeed = interpolate2d(tps.Value, config->tcu_tccTpsBins, config->tcu_tccUnlockSpeed);
 		if (vss.Value > lockSpeed) {
+			// torqueConverterDuty is only used for a gauge
 			torqueConverterDuty = 100;
 			enginePins.tcuTccOnoffSolenoid.setValue(1);
 		} else if (vss.Value < unlockSpeed) {

firmware/controllers/tcu/tc_4l6x.cpp

@@ -39,7 +39,7 @@ void Gm4l6xTransmissionController::set32State(gear_e gear) {
 		if (!vss.Valid) {
 			return;
 		}
-		//huh?uint8_t (*pcts)[sizeof(config->tcu_32SpeedBins)/sizeof(config->tcu_32SpeedBins[0])];
+
 		int pct = interpolate2d(vss.Value, config->tcu_32SpeedBins, config->tcu_32Vals);
 		shift32Pwm.setSimplePwmDutyCycle(pct*0.01);
 	} else {

firmware/controllers/tcu/tcu.cpp

@@ -38,6 +38,7 @@ void TransmissionControllerBase::postState() {
 #endif
 }
 
+// call to mark the start of the shift
 void TransmissionControllerBase::measureShiftTime(gear_e gear) {
 	m_shiftTime = true;
 	m_shiftTimer.reset();
@@ -47,13 +48,17 @@ void TransmissionControllerBase::measureShiftTime(gear_e gear) {
 float TransmissionControllerBase::isShiftCompleted() {
 	auto detected = Sensor::get(SensorType::DetectedGear);
 	auto iss = Sensor::get(SensorType::InputShaftSpeed);
+	// If gear detection is set up and the gear we are trying to shift into has been detected
 	if (detected.Valid && m_shiftTime && m_shiftTimeGear == detected.Value) {
 		m_shiftTime = false;
 		return m_shiftTimer.getElapsedSeconds();
+		// If ISS isn't configured, we want to use a fixed value.
 	} else if (!iss.Valid && m_shiftTime && m_shiftTimer.hasElapsedMs(config->tcu_shiftTime)) {
 		m_shiftTime = false;
+		// convert ms to seconds for gauge
 		return config->tcu_shiftTime * 0.001;
 	} else {
+		// a return value of 0 means the shift is not completed yet
 		return 0;
 	}
 }