Flash Rom Functions; Power Button Functions - Compaq EN Series Technical Reference Manual

8.4.6

FLASH ROM FUNCTIONS

The system BIOS may be upgraded by flashing the ROM using the INT 15, AX=E822h BIOS
interface, which includes the necessary subfunctions. An upgrade utility is provided on a
ROMPAQ diskette. The upgrade procedure is described at the end of this chapter. Corrupted
BIOS code will be indicated by the keyboard LEDs during the boot sequence as described
previously in section 8.2.1.
8.4.7

POWER BUTTON FUNCTIONS

The BIOS includes an interface for controlling the system unit's power button. The power button
can be disabled and enabled. The INT 15, AX=E822h, BL=08h function can be invoked to
disable the power button, preventing a user from inadvertently powering down the system. This
tri-modal function is typically used in the ROM flashing procedure to reduce the chance of an
accidental power down while the BIOS is being upgraded.
Entry:
AX = E822h
BL = 08h
Return:
(Successful)
CF
AH
(Failure)
CF
AH
NOTE: With the Disable function invoked the system can still be powered down by
holding the power button in for four seconds or more.
The INT 15, AX=E822h, BL=09h function is used to restore the power button to the state it was
in prior to invoking the Disable (BL=08h) function.
Entry:
AX = E822h
BL = 09h
R e t u r n :
R e t u r n :
( S u c c e s s f u l )
( S u c c e s s f u l )
CF
AH
(Failure)
CF
AH
= 0
= 00
= 1
= 86, not supported
= 0
= 00
= 1
= 86, call not supported
Compaq Deskpro EN Series of Personal Computers
First Edition - June 1998
Technical Reference Guide
Net PC and Small Form Factor Models
8-15