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Microprocessor-Controlled Visual Diagnostic And Status Indicator Employing a Finite-Length Repeating Binary Code Sequence

IP.com Disclosure Number: IPCOM000099675D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 118K

Publishing Venue

IBM

Related People

Boudreaux, R: AUTHOR [+8]

Abstract

This article describes a method of communicating status and error information from a device or circuit board to an operator by employing a light-emitting diode (LED) to flash a repeating binary coded error status message.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 51% of the total text.

Microprocessor-Controlled Visual Diagnostic And Status Indicator Employing a Finite-Length Repeating Binary Code Sequence

       This article describes a method of communicating status
and error information from a device or circuit board to an operator
by employing a light-emitting diode (LED) to flash a repeating binary
coded error status message.

      The method disclosed herein is implemented by providing a
device or circuit board with a microprocessor-controlled LED which
can be turned on or off under program control. When the device needs
to communicate an error or status condition it will turn the LED
indicator on and off in such a way as to produce a series of long
and short flashes. Each flash of long duration represents a binary
'1' and each short duration flash represents a binary '0'.  By
concatenating these long and/or short flashes together, the device
may convey a string of binary digits which may represent any
arbitrary binary number.  For example, in order to send a binary '1'
the LED will turn on for a relatively long period of time (two
seconds).  Conversely, to send a binary '0' the LED will turn on for
a relatively short period of time (for example, one second).  Between
sending each binary digit (each '0' or '1'), the LED will turn off
for a short period of time.  One second is adequate.  By
concatenating these binary digits together, the LED can be made to
flash any number desired.  For example, to flash the binary number
'10110' (hexadecimal '16'), the LED would turn on and off as
illustrated in the timing chart of the drawing.

      The flash code emitted from the LED can be used to signal error
or status information about the device.  For example, a circuit card
in a computer system might indicate that a particular component had
failed by flashing the binary code '10110' (hexadecimal 16).  A
customer service representative (CSR) servicing the system would
observe the flash code and look up the meaning of it in a repair
manual. The repair manual can then suggest the proper service
procedure for the particular flash code being encountered.

      Normally, it is advantageous to flash the error/status code
repeatedly for as long as the condition remains valid. This is easily
accomplished by separating each flash code sequence by a relatively
long space, perhaps five seconds. Such a space allows the observer to
easily recognize the beginning of each flash code sequence.

      The LED error/status flasher scheme can be implemented in an
attachment card.  A diagnostic LED is provided on this device which
is capable of indicating a number of system malfunctions as well as
aiding in diagnostic field replaceable unit (FRU) isolation and
system maintenance.  In the case of the attachment card a total of 32
error codes would be sufficient to encode any diagnostic or status
information that might need to be communicated to the CSR. The number
of binary digits required to represent 32 unique co...