Abstract: A wireless communication device (100) includes a display (120) having a backlight (124). A backlight controller (126) selectively enables the backlight (124) to minimize power consumption and conserve energy in a battery (132). In one embodiment, a receiver (110) receives a time-of-day message from a remote location to set a timer (122) with the current time-of-day. The current time-of-day is compared with a predetermined time-of-day and the backlight controller (126) enables and disables the backlight (124) at predetermined times-of-day. The wireless communication device (100) may also include a GPS receiver (128), to determine the location of the device. The backlight controller (126) can determine the sunrise or sunset times for the specific location. The GPS data may be used in combination with the time-of-day message. A photosensor (130) can detect ambient light levels and generate an electrical signal corresponding thereto.

Abstract: Where the same data is stored for an extended period of time, the possibility exists of unwanted burning in of the data which would allow undesired recovery of erased data even after it has been over-written or the memory has been powered down. The memory contents are therefore periodically rewritten in the inverse of their former state, either to the same location in which they were previously stored, or elsewhere. Inversion may be performed in an invert cycle during which address decoders driven by a high speed oscillator read each cell and write back its contents inverted. On completion of a cycle, a latch may indicate whether the stored data is in a true or complement form. The latch may control programmable invertors so that cells are always read or written correctly, regardless of whether data happens to be in true or complement form.