HVAC_POWER_ON
What it is
Represents global power state for HVAC. Setting this property to false MAY mark some properties that control individual HVAC features/subsystems to UNAVAILABLE state. Setting this property to true MAY mark some properties that control individual HVAC features/subsystems to AVAILABLE state (unless any/all of them are UNAVAILABLE on their own individual merits).
[Definition] HvacPower_DependentProperties: Properties that need HVAC to be powered on in order to enable their functionality. For example, in some cars, in order to turn on the AC, HVAC must be powered on first.
HvacPower_DependentProperties list must be set in the VehiclePropConfig.configArray. HvacPower_DependentProperties must only contain properties that are associated with VehicleArea:SEAT. Properties that are not associated with VehicleArea:SEAT, for example, HVAC_DEFROSTER, must never depend on HVAC_POWER_ON property and must never be part of HvacPower_DependentProperties list.
AreaID mapping for HVAC_POWER_ON property must contain all AreaIDs that HvacPower_DependentProperties are mapped to.
Example 1: A car has two front seats (ROW_1_LEFT, ROW_1_RIGHT) and three back seats (ROW_2_LEFT, ROW_2_CENTER, ROW_2_RIGHT). If the HVAC features (AC, Temperature etc.) throughout the car are dependent on a single HVAC power controller then HVAC_POWER_ON must be mapped to [ROW_1_LEFT | ROW_1_RIGHT | ROW_2_LEFT | ROW_2_CENTER | ROW_2_RIGHT].
Example 2: A car has two seats in the front row (ROW_1_LEFT, ROW_1_RIGHT) and three seats in the second (ROW_2_LEFT, ROW_2_CENTER, ROW_2_RIGHT) and third rows (ROW_3_LEFT, ROW_3_CENTER, ROW_3_RIGHT). If the car has temperature controllers in the front row which can operate entirely independently of temperature controllers in the back of the vehicle, then HVAC_POWER_ON must be mapped to a two element array: - ROW_1_LEFT | ROW_1_RIGHT - ROW_2_LEFT | ROW_2_CENTER | ROW_2_RIGHT | ROW_3_LEFT | ROW_3_CENTER | ROW_3_RIGHT
This property is defined as VehiclePropertyAccess.READ_WRITE, but OEMs have the option to implement it as VehiclePropertyAccess.READ only.
How the ID is built
A property ID is a 32-bit value packing four fields. Reading 0x15200510 apart:
| Field | Mask | Value | Means |
|---|---|---|---|
| Group | 0xf0000000 | 0x10000000 | SYSTEM |
| Area | 0x0f000000 | 0x05000000 | SEAT |
| Type | 0x00ff0000 | 0x00200000 | BOOLEAN |
| Ordinal | 0x0000ffff | 0x00000510 | 0x510 |
Reading it from an app
CarPropertyManager mgr = (CarPropertyManager)
car.getCarManager(Car.PROPERTY_SERVICE);
boolean value =
mgr.getBooleanProperty(VehiclePropertyIds.HVAC_POWER_ON, areaId);This property can be read and written, though an OEM may implement it as read-only. It fires a callback whenever the value changes.