Intermec 6100 Reference Guide

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CPU Idle, INT 15h, AX=5305h, is an APM BIOS function.  Refer to the CPU Idle

definition, on page 6Ć78, for details on usage.
A call to this function causes the processor to halt (via the HLT instruction) until

the next hardware interrupt.  This causes good power savings, if it is used during

input polling loops, or other low activity points in an application.
Refer to the Intel APM BIOS Interface specification 1.1 or Ralf Brown's Interrupt

List for more information.
Refer to Appendix B, Common PEN*KEY 6000 Series Information, for a sample

listing (IDLE.CPP) showing the use of the CPU Idle interrupt.

This is the core BIOS supported for the 6100 Computer.  Starting with flash verĆ

sion 1.11, the following features are added to the core BIOS:

"

Suspend/resume coordination (suspend/resume key mapped to I/O key, if

IO2SUS.COM is loaded):

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to work with NORAND Card and Socket services

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and for radio integration

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COM4 timeout for the BIOS data area

The detailed definitions for the PC BIOS interfaces supported for the 6100 ComĆ

puter are described in the paragraph.  The following paragraphs summarize the

supported interrupts, as well as the unsupported interrupts.
Only some of the 4000 Series BIOS interrupts are supported by the 6100 ComĆ

puter, as described in the following paragraphs:

There are two indexes provided for the details of the BIOS interface functions

supported for the 6100 Computer.  To find an interrupt by its name, refer to the

Interrupt Index, at the end of this publication.  To locate an interrupt by the inĆ

terrupt number, refer to the Interrupt CrossĆReference table, on page 6Ć28.

The system provides a periodic system timer tick and issues interrupt 8 at every

timer tick.  The interrupt occurs approximately every 55 milliseconds.  This rate

is close to 65535 ticks per hour.
The interrupt service routine maintains the count of interrupts from powerĆon at

BIOS data location 0x40:0x6C.  After 24 hours of operation, location 0x40:0x7C

is nonzero when the counter overflows to the next day.  The number of ticks in 24

hours is 0x1800B0.
The system timer interrupt issues a call to a userĆsupplied routine through interĆ

rupt 0x1C at every interrupt.
Application programs should avoid using the Timer Tick as much as possible,

since many applications are already hooked into it and it could become overĆ

loaded.