Overriding a Bad Battery Indicator If Configuration Information is Correct
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Eng, RC: AUTHOR [+2]
This article describes a method and hardware enablement for alerting an industrial personal computer (PC) system when the system resource card is removed from the system.
Overriding a Bad Battery Indicator If Configuration
describes a method and hardware enablement
for alerting an industrial personal computer (PC) system when the
system resource card is removed from the system.
In an industrial computer designed for
ease of maintenance, high performance, and unattended operation is
required. The system enclosure differs from conventional PC
machines. It holds cards in shrouds which plug into the front of the
unit. Instead of a planar board, there are two system cards, a
processor card and a system resource card, which plug into a passive
backplane. The processor card contains a microprocessor, cache, math
coprocessor, and system ROM. The system resource card provides
interfaces for keyboard, video, diskette, and communications. It
also holds system configuration information. An optional two-slot
module that contains the diskette and fixed disk drives is called the
direct access storage device (DASD) module. The system also contains
a modular power supply that is front pluggable.
The ease in
removing shrouds from the system poses unique
problems in retaining system configuration information. The
configuration information is held in complementary metal-oxide
semi-conductor (CMOS) on the system resource card. While the system
resource card is in the system, its CMOS is powered by the power
supply or the back-up battery. Once the system resource card or the
power supply is removed from the system, a capacitor is depended upon
to power the CMOS.
The method of
alert disclosed herein should only occur when the
system configuration information is invalid. Additional intelligence
is needed in the system ROM initialization program to handle this new
information. Without added intelligence, the system ROM generates an
error message after power is applied to the system, requiring a
system configuration program to clear the error.
The real time
clock (RTC) chip circuit shown in Fig. 1 is
designed to sense the disruption of a power source and set a bad
battery flag. ...