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Browse Prior Art Database

Trace Array

IP.com Disclosure Number: IPCOM000108952D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 3 page(s) / 82K

Publishing Venue

IBM

Related People

Grosbach, LE: AUTHOR [+3]

Abstract

A logic analyzer function is implemented internal to a multi-chip module (MCM) and controllable by microcode. The analyzer stores signal data in an array and provides different trace modes, selectable triggers, selectable inputs, and an external (common) trigger line. The external trigger connects to all trace arrays in a multiprocessor environment and allows synchronizing all the logic traces when a trigger occurs.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Trace Array

       A logic analyzer function is implemented internal to a
multi-chip module (MCM) and controllable by microcode.  The analyzer
stores signal data in an array and provides different trace modes,
selectable triggers, selectable inputs, and an external (common)
trigger line.  The external trigger connects to all trace arrays in a
multiprocessor environment and allows synchronizing all the logic
traces when a trigger occurs.

      Enough signals are stored in the trace array to allow efficient
debug of the system.  Both MCM internal only and externally available
signals are stored in the trace array.  Signals being stored include
major control interfaces and sequencers.

      Referring to the figure, microcode uses the processor interface
1 to load the control register 2 and mask register 3 to initialize
and enable the trace array function.  The control register 2 contains
the following functions:
o    Controls selection of trace mode
      -    Store data every cycle.
      -    Store data every control word.
      -    Store data every instruction.
o    Controls selection of data inputs used to feed the trigger logic
4
o    Selects what type of trigger is used
      -    'OR' of trigger inputs.
      -    Compare trigger inputs with data in a portion of the mask
register 3.
      -    External trigger 8.
o    Enable one or more of the trigger types
o    Selects the interrupt type issued to the processor
      -    Trap.
      -    Exception.
o    Contains a constant for the number of events saved in the trace
array after a trigger occurs.

      The mask register 3 contains the mask data and compare data
used by the trigger logic 4.  The mask data is used to ignore (don't
care) specified...