If a Low Battery NMI event occurs, the HP palmtop enters the deep sleep state as quickly as possible. Checksums for User RAM, CPU registers, and hardware registers are not computed. The various power-consuming devices (keyboard, IR, UART, display, DAC, etc.) are turned off as rapidly as possible. Wakeups from this state are inhibited until the power supply is again operational (installation of a fresh set of batteries or an AC adaptor). The wakeup always results in a warmstart.