| 摘要 |
A method and apparatus for managing power consumption of a communications accessory attached to a vehicle based on the state of vehicle's ignition and upon the power on/off history of the wireless communications device attached to the communications accessory. The method determines whether the last powering off of the wireless communications device was due to user action. If so, then the wireless communications device is left in a powered off state when the ignition is turned back on. If, instead, the last powering off of the wireless communications device was in response to an automatically generated request from the communications accessory (prompted by the ignition being turned off), the wireless communications device is powered back on when the ignition is turned back on. An ignition sense circuit determines the power state of the vehicle's ignition and tracks the recent power on/off history of the wireless communications device. Based on information from the ignition sense circuit, power control logic automatically turns the wireless communications device back on according to the method when the vehicle's ignition is turned back on. In addition, the correctness of the ignition sense line installation may be checked via a combination of a status flag and a suitable timer. If the timer expires, the status flag is set to indicate an improper installation of the ignition sense line. |
