Specifications

Theory of Operation
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(Front
Panel)
(Bottom)
1
Gently lift
retaining clip
2
Slide battery
in/out in line with
the direction of the
retaining clip
Figure 2: Battery Replacement
Replacing the battery is a simple task. However, removing the battery will invalidate
the CMOS setup parameters. It is recommended that all setup parameters be recorded
in a safe place while the battery is still good.
Video Controllers
The EPC can operate with or without a video controller (such as the EXM-6 or EXM-
13). The BIOS searches for an EXM having an EXM ID in the range
E8h-EFh (a range reserved for video controllers). The search is done by EXM slot
number, beginning at slot 0. If no EXM video adapter is found, the BIOS will look
for a PC add-in card with video BIOS. The CPU scans the memory space from
A0000h to C8000h looking for any memory location containing the value AA55h. If
such memory is found (add-in card BIOS ROM), the main BIOS will "jump" into the
add-in card BIOS and execute whatever code is found.
In either case, the BIOS automatically initializes and uses the first one found.
If no video controller is present, the BIOS will operate without one. Programs that
use the standard operating system and BIOS character output functions can be run
successfully (the output is just ignored). However, programs that rely on specific
video modes, that write directly into the video RAM, or that directly call video BIOS
functions, will fail.