Intermec 6200 Reference Guide

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System power states are managed through the use of activity monitors, activity

timers, and function calls from APM device drivers or APMĆaware applications.
Activity monitors are hardwareĆspecific devices that watch for I/O to predefined

I/O devices and I/O addresses.  Both 6200 and 6300 Systems have activity

monitors for the following I/O devices.  When a device is accessed, a bit in the

activity monitor for the device is set.

Table 4Ć1 

I/O Address (Hex) Device
0CE, 0ED

Scamp (ECh,EDh)

208ć20F

Digitizer

360ć377

LAN

3B0ć3DF

VGA (I/O and memory activity (0A0000hć0BFFFFFh)

3F8ć3FF

COM1 (3F8hć3FFh)

2F8ć2FF

COM2 (2F8ć2FFh)

3E0ć3E1

PC Card (I/O activity, slot control, and page frame access)

00ć0F

80ć8F

0C0ć0DF





DMA (

I/O activity to both controller and DMA page registers

)



060, 064

Keyboard (60h and 64h)

3E8ć3EF

COM3

2E8ć2EF

COM4

1E8ć1EF

Internal scanner

220ć224

SST radio

1F0ć1F7

PC Card ATA drive

Activity timers are defined for System Idle and System Suspend.  These timers

are enabled by default and their timeout period can be set or retrieved by OEM

APM functions Set Device Activity Timer or Get Device Activity Timer.  These

timers decrement when no system activity occurs within 0.125 second and are

reset to the defined period when activity occurs within 0.125 second.  If Idle or

Suspend timeout is set to zero, the activity timer is disabled.  When activity

timers decrement to zero, the system power state associated with the timer is

entered (System Idle or System Suspend).
Activity monitors can be masked so that activity on a given device is ignored and

not cause the activity timers to be reset when activity occurs on the masked

device.  OEM APM functions Set Device Activity Mask and Get Device Activity

Mask are provided for this purpose.
CPU IDLE, CPU BUSY, and System Suspend are functions that affect system

power states.  Set Power State invokes System Suspend for device 0001h.  APM

Drivers or APMĆaware applications may make these function calls.
The CPU IDLE call causes the system to enter a lowĆpower state by decreasing

the system clock frequency and issuing a HALT instruction to the CPU.  The idle

state may also be entered whenever there is a lack of system activity if the IDLE

activity timer is nonzero.  The IDLE state is exited whenever an interrupt

service routine is invoked that causes I/O activity or performs a CPU BUSY call.

The IDLE state returns to the READY (full power state) in this condition.