74F632QC NSC [National Semiconductor], 74F632QC Datasheet - Page 6

• Manufacturer Part Number: 74F632QC
• Description: 32-Bit Parallel Error Detection and Correction Circuit
• Manufacturer: NSC [National Semiconductor]

Functional Description
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
6
5
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Syndrome Bits
4
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
3
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
2
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
(Continued)
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
1
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
TABLE V Syndrome Decoding (Continued)
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
0
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
Error
DB
DB
DB
DB
DB
DB
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
DB
DB
CB
unc
unc
unc
unc
unc
unc
unc
15
14
13
12
11
10
5
9
8
6
CB
DB
2-Bit
unc
Note 2-bit and unc condition will cause both ERR and MERR to be LOW
Note 1 Syndrome bits for all LOWs MERR and ERR LOW for all LOWs
only ERR LOW for DB
Note 2 Syndrome bits for all HIGHs
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
6
X
Y
e
e
e
e
Uncorrectable multi-bit error
Error in check bit X
Error in data bit Y
Double-bit error
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
5
Syndrome Bits
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
4
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
30
error
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
3
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
2
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
1
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
0
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
unc (Note 1)
Error
DB
DB
DB
DB
DB
DB
DB
DB
None
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
2-Bit
CB
CB
CB
CB
CB
unc
unc
23
22
21
20
19
18
16
17
4
3
2
1
0