Browse Prior Art Database

Printer Port Check Point Card

IP.com Disclosure Number: IPCOM000122455D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Dang, TT: AUTHOR

Abstract

This article describes a pluggable circuit card with two hexadecimal displays. This card is plugged into a printer port and used as a diagnostic tool to isolate system problems.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 84% of the total text.

Printer Port Check Point Card

      This article describes a pluggable circuit card with two
hexadecimal displays.  This card is plugged into a printer port and
used as a diagnostic tool to isolate system problems.

      Some personal computers (PCs) do not provide system status
during power-on self-test (POST) until the monitor is initialized to
display the installed memory size.  If an error occurred during this
period, it is difficult to diagnose the problem, especially in a
normal user or manufacturing environment.  The printer port
check-point card disclosed herein provides an effective way to solve
this problem.

      Fig. 1 is a functional block diagram showing the design of the
circuit card of this disclosure.  It uses three readily available
components as follows:
1.   25-Pin Male D-Shell Connector - to be connected to system
parallel port.
2.   25-Pin Female D-Shell Connector - to be connected to printer
device, if required.
3.   Two hexadecimal display modules U1 and U2 TIL311 from Texas
Instruments - it contains a 4-bit latch, decoder, driver, and 4x7
light-emitting-diode (LED) character.

      In order to monitor progress and status of the system's POST
through the planar board's printer port, the lower-order printer data
bits (D0-D3) are connected to display module U2 and the higher-order
printer data bits (D4-D7) are connected to display module U1.  As the
system encounters an error at a particular checkpoint such as a non-
maska...