Browse Prior Art Database

LED Display Intercepter and Converter Card

IP.com Disclosure Number: IPCOM000106718D
Original Publication Date: 1993-Dec-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Armstrong, CJ: AUTHOR

Abstract

Disclosed is a circuit for the interception of RISC/6000 LED display signals, and the conversion of these signals from seven-segment to Binary Coded Decimal (BCD) format. The converted signals are gated through two buffers to the parallel port of a PC, where they are read by software and converted into the original 3 digit LED number.

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LED Display Intercepter and Converter Card

      Disclosed is a circuit for the interception of RISC/6000 LED
display signals, and the conversion of these signals from
seven-segment to Binary Coded Decimal (BCD) format.  The converted
signals are gated through two buffers to the parallel port of a PC,
where they are read by software and converted into the original 3
digit LED number.

      On the LED Display Interceptor and Converter Card is a set of
two identical 2X13 connectors, so that if desired, signals can be run
from the RISC/6000 planar where they originate to the LED Display
Interceptor and Converter Card, and then on to the operator panel or
LED display of the system itself.  Of the 34 signals available, only
22 are actually used by the LED Display Interceptor and Converter
Card.  Twenty one of the signals used are for a 3 digit seven-segment
display, and one is for a reset signal.  The connection to the reset
signal line is to allow a reset signal to be sent to the RISC/6000
system from software running on the connected PC.  Note that an
active high reset signal is assumed.

      The 22 seven-segment LED signals are each converted to TTL
level signals using 6 LM339M voltage comparators.  The voltage used
for comparison is determined by a voltage divider circuit that is
connected to 5 volts.  As different types of LED's require different
voltages to determine their on or off condition, the resistor values
needed for the voltage divider will not always be the same, therefore
the resi...