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Optimized Parity Generator in ALTERA Field Programmable Gate Array (MAX7xxx Parts)

IP.com Disclosure Number: IPCOM000118764D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 58K

Publishing Venue

IBM

Related People

Gorzegno, F: AUTHOR [+2]

Abstract

MAX+PLUS II requires thirteen macrocells to map the following equation into a MAX7XXX device. 8 inputs XOR Y = A xor B xor C xor D xor E xor F xor G xor H

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 55% of the total text.

Optimized Parity Generator in ALTERA Field Programmable Gate Array
(MAX7xxx Parts)

      MAX+PLUS II requires thirteen macrocells to map the following
equation into a MAX7XXX device.
     8 inputs XOR
   Y = A xor B xor C xor D xor E xor F xor G xor H

An overview of the Macrocell is shown in Fig. 1.

In summary, a macrocell has the ability to fit a five product terms
equation.

      Byte Parity Generator mapping

      An eight inputs xor generates a one hundred and twenty eight
product terms equation.

      When MAX+PLUS II synthesizes the eight inputs xor, it keeps the
last input (h input) for the XOR gate of the last macrocell.  Then it
must develop a seven entries xor equation that generates sixty-four
product terms.  These sixty-four product terms are mapped into
thirteen macrocells:  five product terms x thirteen macrocells =
sixty-five product terms
  MAX+PLUS II uses thirteen macrocells to map a Byte Parity
   Generator.

This disclosure provides the following solution: A macrocell has the
ability to fit a four inputs xor equation.
  o  three inputs (generating a four product terms equation) are
      mapped into the interconnect matrix and the product term
      select matrix.
  o  the last input is routed to the XOR gate of the macrocell.
  Cell mapping
  1.  The first macrocell is used to map the
       (A xor B xor C xor D) equation.
  2.  The second macrocell is used to map the
       (E xor F xor G xor...