In the on state, an H/PC uses more power than in the dead or suspend states. Any time the display, keyboard, or touch screen are active, an H/PC is in the on state. When in the on state, an H/PC can switch between two processor modes: full speed and idle. In full-speed mode, the processor runs at normal operating frequency. In idle mode, the internal processor clock stops, and the processor uses little power. Peripherals and DRAM may be on or off. The processor can enter and exit this state in approximately 10 milliseconds. An H/PC switches to the on state when one of the following events take place:
In the on state, the default mode is full speed. An H/PC switches from full-speed mode to idle mode when all processes are idle. Switching to idle mode is transparent to the user and most applications because the system continues to process interrupts, including the time-slice interrupt.