Browse Prior Art Database

Determining Scan Ring Order Without Simulation

IP.com Disclosure Number: IPCOM000100026D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Setlak, PJ: AUTHOR [+2]

Abstract

Disclosed is a method for determining the order of a scan ring in a processor design using Level Sensitive Scan Design rules.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 60% of the total text.

Determining Scan Ring Order Without Simulation

       Disclosed is a method for determining the order of a scan
ring in a processor design using Level Sensitive Scan Design rules.

      The order of a scan ring is determined by tracing back from the
given primary scan ring output to the given primary scan ring input.
The algorithm shown in the drawing figure is controlled by the end
decision (1).  When the scan ring pointer SCAN-RING-PTR references
the primary scan ring input, the process is finished.

      SCAN-RING-PTR marks the net that is the algorithm's present
position in the scan ring.  Get block (2) retrieves the source block
SOURCE-BLOCK of the net referenced by SCAN-RING-PTR.  SOURCE-BLOCK is
the block that drives a net. Classify block (3) consults a rules base
to obtain the characteristics of SOURCE-BLOCK.  One of these
characteristics is whether or not SOURCE-BLOCK can be a scan ring
element.  The rule for SOURCE-BLOCK will also classify the input and
output pins of SOURCE-BLOCK and specify the number of latches
contained in SOURCE- BLOCK.

      A trace back step is performed when SCAN-RING-PTR is modified
to reference the appropriate input net of SOURCE-BLOCK.  The
appropriate input net is identified one of three ways.
      1.   When SOURCE-BLOCK is identified as a scan ring element
(4), the scan ring element process (5) is invoked.  SCAN-RING-PTR is
modified to reference the scan ring element's scan input.  A
reference to SO...