6 - 12
6 - 12
6. HOW TO COMMUNICATE WITH ID TAGS
6.2.11 Read with error correction
The Read with Error Correction command reads from the ID tag the number of byte sets
specified in the number of processed points specification area (Un
\
G4, Un
\
G4004) +
the check code (five bytes) from the address specified in the head address specification
area (Un
\
G3, Un
\
G4003), and checks the correctness of the data from the check code.
When a 1-bit memory error is corrected, the data correction flag (bit 3) of the error
details storage area (Un
\
G41, Un
\
G4041) turns ON and error detection (X5, XD) turns
ON. The normal data after error correction are stored in the data storage area
(Un
\
G100 to UN
\
G1123, UN
\
G4100 to Un
\
G5123).
For details of the error correction function, refer Section 5.6, “ID Tag Memory Error
Correction Function”.
(1) Example of use
(a) When executing the Read with Error Correction command in the data storage
order 0000
H
(upper -> lower), for the four bytes from address 0010
H
.
0F
H
0018
H
12
H
34
H
56
H
78
H
0010
H
0013
H
0012
H
F0
H
67
H
0015
H
0014
H
00
H
0C
H
0017
H
0016
H
0011
H
A
B
C
b15
b0
12 34
H
56 78
H
Un\G100
Un\G101
b7
Before
execution
After
execution
Buffer memory
Address
ID tag
A : No. of read bytes (4 bytes)
B : Memory check code (2 bytes)
C : Error correction code (3 bytes)
(b) When executing the Read with Error Correction command in the data storage
order 0000
H
(upper -> lower) for the four bytes from address 0010
H
and a 1-bit
memory error is corrected
Before
execution
After
execution
Buffer memory
Address
ID tag
0F
H
0018
H
02
H
34
H
56
H
78
H
0010
H
0013
H
0012
H
F0
H
67
H
0015
H
0014
H
00
H
0C
H
0017
H
0016
H
0011
H
b15
b0
12 34
H
56 78
H
Un\G100
Un\G101
b7
1-bit memory
error
Executing the
Read with Error
