ACTS630MS

FN3204 Rev 1.00

Page 2 of 4

January 1996

Function Tables

Control Functions

MEMORY

CYCLE

CONTROL

EDAC FUNCTION

DATA I/O

CHECKWORD

ERROR FLAGS

S1

S0

SEF

DEF

WRITE

Low

Low

Generates Checkword

Input Data

Output Checkword

Low

Low

READ

Low

High

Read Data and Check-

word

Input Data

Input Checkword

Low

Low

READ

High

High

Latch and Flag Error

Latch Data

Latch Checkword

Enabled

Enabled

READ

High

Low

Correct Data Word and

Generate Syndrome Bits

Output Corrected

Data

Output Syndrome

Bits

Enabled

Enabled

Check Word Generation

CHECKWORD BIT

16-BIT DATA WORD

0123456789

10

11

12

13

14

15

CB0

X

X

X

X

XXX

X

CB1

X

XX

XX

X

X

X

CB2

X

XX

XXX

X

X

CB3

X

X

X

XX

XXX

CB4

XXXXX

XXX

CB5

XXXXXXXX

NOTE: The six check bits are parity bits derived from the matrix of data bits as indicated by “x” for each bit

Error Syndrome Codes

SYNDROME

ERROR

CODE

ERROR LOCATIONS

DB

CB

NO

ERROR

0123456789

10

11

12

13

14

15

012345

CB0

L

L

H

L

L

HHH

L

L

L

HH

L

H

H

L

HHHHH

H

CB1

L

H

L

L

H

L

L

H

L

HH

L

H

H

L

HH

L

HHHH

H

CB2

H

L

L

HL

LHLHLH

HLH

H

LH

HLH

H

H

H

CB3

L

L

L

HHH

L

L

HH

L

L

L

HHHHHH

L

H

H

H

CB4

H

H

H

LLLLL

HHHHH

L

L

L

HHHH

L

H

H

CB5

HHHHHHHH

LLLLLLLL

HHHHH

L

H

Error Functions

TOTAL NUMBER OF ERRORS

ERROR FLAGS

DATA CORRECTION

16-BIT DATA

6-BIT CHECKWORD

SEF

DEF

0

0

Low

Low

Not Applicable

1

0

High

Low

Correction

0

1

High

Low

Correction

1

1

High

High

Interrupt

2

0

High

High

Interrupt

0

2

High

High

Interrupt