Intermec 6200 Reference Guide

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NORAPM.EXE is the APM BIOS.  The APM system consists of one or more

layers of software.  The APM BIOS resides at the lowest layer.
To provide portability at the higher layers of the APM system, NORAPM.EXE,

an installable DOS device driver, provides a software interface to the hardware

that is independent of the hardware interfaces.
However, to provide diagnostics with proprietary applications, functions specific

to Intermec Technologies Corporation, are also provided.  These functions may

not be independent of the hardware interfaces.
The layer immediately above the APM BIOS includes the operating system

power management driver.  For DOSĆbased systems, the device driver is

NPOWER.EXE.  For Windows applications, the device driver is NORAPM.DLL.

The operating system driver is responsible for the power management strategy.

This includes system power state and device power state transitions.  The driver

is also responsible for the application interfaces.
The highest layer includes applications that are APMĆaware.  Applications

receive power messages only from the APM driver.  Applications can

communicate with either the APM driver or the APM BIOS.
The objective of APM is to control the power usage of the system according to

system activity.  As system activity decreases, APM reduces the power

consumption of system resources until the system is brought into a suspend

state.
There are two methods of powerĆlevel control:

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The APM BIOS manages CPU/core logic, display, and backlight power in

the background, based on device activity.

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An APM driver participates in managing power levels via function calls to

the APM software interface.

For more information relating to these drivers, see Section 2 for DOS Power

Management and Section 3 for Windows Power Management.

NORAPM has three default system power states:

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Ready ( full on )

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Idle

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APM suspend.

The primary difference between states is the latency needed for the system to

reach full operation.  Power consumption and performance are greatest in the

Ready state and decrease with each succeeding state.

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System Ready is the default mode when the system is not engaged in power

management.

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System Idle is the first level of power management.  The CPU is halted and

the system clock speed is reduced.  Transitions from Idle to Ready are

instant.

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System Suspend is the second level of power management.  The CPU clock

is stopped and devices are placed into the power state defined by the

application for System Suspend.  The device power state for suspend can be

any power state defined for that device.  The exact definition of a device

power state during suspend is performed by using the Set Power State, Get

Power State, and Enable/Disable Device Power Management functions.

Transitions from suspend to ready generally take 100 milliseconds.