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SYNDROME GENERATION FOR MC68540

IP.com Disclosure Number: IPCOM000005465D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2001-Oct-10
Document File: 1 page(s) / 43K

Publishing Venue

Motorola

Related People

Gary Hinton: AUTHOR

Abstract

The MC66540 uses a modified Hamming code to generate six syndrome bits and six check bits to per- form Single Error Correction and Double Error Detection (SECKIED) on a data pattern of 16 bits. Two such devices can be used in tandem to generate the seven syndromes and check bits necessary to do error detection and correction on 32 data bits. The parts are able to operate in parallel by passing partial syn- dromes between them.

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SYNDROME GENERATION FOR MC68540

By Gary Hinton

   The MC66540 uses a modified Hamming code to generate six syndrome bits and six check bits to per- form Single Error Correction and Double Error Detection (SECKIED) on a data pattern of 16 bits. Two such devices can be used in tandem to generate the seven syndromes and check bits necessary to do error detection and correction on 32 data bits. The parts are able to operate in parallel by passing partial syn- dromes between them.

   The syndrome pattern selection has been uniquely defined so that when it is flipped over, top for bot- tom, and then shifted down by one syndrome bit position, the combination of this and the original will produce a unique table capable of generating the required seven syndromes and check bits for a 32.bit data pattern. This flip and shift method is the way the partial syndromes are combined within each part. Since both parts will calculate the total seven syndrome bits, they are both capable of indicating the er- rors and correcting the error bit within itself.

smDantlE DATA CHECK

SITS BITS BITS

4

0 I 2 s 4 5 0 7 s s 10 I, 12 1s I. I.5 1s 17 1s 1s 20 21 22 2, 21 25 *s 27 28 29 so 3, !a I 2 3 4 6 *

so ..". . ..* . . . . . . .

5, "..... . . . . . . . . . . . . .

s2 . . . . . . . . . l LI -... . "

55 * . ."..I . . . . . ".... . . . .

54 l . . . . . . I) . . . .*. . . .

ss . . . . . . * . . . * . l . . . . . .

se " . . . . . . . . . . . . . .

TOTAL SYSTEM SYNDROME

50

0 Motorola, Inc. 1982

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