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Sticky Strobe - Sticky Bit And Frequency Indicator On One Pin

IP.com Disclosure Number: IPCOM000100901D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Brodnax, T: AUTHOR [+5]

Abstract

Disclosed is a method for using one output pin on an integrated circuit to indicate that an event has happened at least one time and to count the number of times which the event occurs.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 73% of the total text.

Sticky Strobe - Sticky Bit And Frequency Indicator On One Pin

       Disclosed is a method for using one output pin on an
integrated circuit to indicate that an event has happened at least
one time and to count the number of times which the event occurs.

      The goal of the sticky strobe circuit is to perform two related
functions on one pin.  A sticky bit is used to indicate whether or
not an event ever took place. Traditionally, the output of a sticky
bit register is zero until the event takes place.  After the event,
the output will be one regardless of how often, if ever again, the
event takes place.  Thus, the sticky bit does not give the observer
any indication of the frequency of the event.  A signal which
indicates that an event has taken place in the current cycle can
indicate frequency if the observer counts the number of cycles in
which the line is high.  This indicator would have to be monitored
every cycle to know if the event ever took place - not always
desirable.

      The sticky strobe is low until the first error.  After the
first error, it is high except during cycles with subsequent errors.
Therefore, this circuit's output could be monitored by a counter, or
it could be used to drive an indicator light (or both simultaneously
without requiring two pins.  A timing diagram shows the sticky
strobe's operation in a typical data stream in Figure 1.

      The design of the sticky strobe is very straightforward, as
seen in Figure 2....