Abstract: Methods and apparatus are provided for reserving power in a handheld computer by inducing a sleep mode when the energy supply of the handheld computer reaches a predetermined low level. A software is provided which operates a sleep mode when a device of the handheld computer detects a predetermined low battery voltage. A processor operates the software to place the handheld computer in a low energy-consuming shutdown state in which an interrupt controller operates to mask those interrupt signals thus providing an user with the impression that the device has entered an unresponsive sleep mode. In maintaining the sleep mode, the processor operates such that all input signals that request the handheld computer to power up remain active but so long as the battery voltage remains below a predetermined voltage the interrupt signals to power up selected applications and devices are masked.

Abstract: Embodiments of the invention provide for operating a handheld computer with multiple time-out periods in a manner that is more efficient and effective for conserving power than previous systems. In an embodiment, the handheld computer implements one or more additional time-out periods by identifying an occurrence of an event that requires the handheld computer to be in the high power state to perform a specific function. An event may include a function such as sounding an alarm, although other events are also encompassed by embodiments of this invention. When an event is identified, the power state of the handheld computer prior to identifying the event is recalled. The handheld computer then implements a time-out period based on its previous power state. In one embodiment, if the handheld computer was in a low-power state prior to the event occurring, the time-out period is shortened.

Abstract: Methods and apparatus are provided for reserving power in a handheld computer by inducing a sleep mode when the energy supply of the handheld computer reaches a predetermined low level. A software is provided which operates a sleep mode when a device of the handheld computer detects a predetermined low battery voltage. A processor operates the software to place the handheld computer in a low energy-consuming shutdown state in which an interrupt controller operates to mask those interrupt signals thus providing an user with the impression that the device has entered an unresponsive sleep mode. In maintaining the sleep mode, the processor operates such that all input signals that request the handheld computer to power up remain active but so long as the battery voltage remains below a predetermined voltage the interrupt signals to power up selected applications and devices are masked.