126
Secti
on 4
RF Tag Memor
y
Error Correctio
n
RFID System
User's Manual
Section 4
Functions
RF Tag Memory Error Correction
The WRITE WITH ERROR CORRECTION command (QW) can be used to write an RF Tag memory check
code and error correction code to the five bytes of memory after the write data. The READ WITH ERROR
CORRECTION command (QR) performs a tag memory check and makes 1-bit memory error corrections.
When a 1-bit memory error is corrected, a warning
that a 1-bit memory error occurred is given by
returning an end code of 77, and the normal data
with the error corrected will be returned. When a 2-
bit or larger memory error is detected, a memory
error (end code 76) saying that error correction was
not possible is given and the read data will not be
returned.
For details on the command format, refer to
READ WITH ERROR CORRECTION (QR)
and
TION (QW)
.
Example of Using the Memory Error Correction Function
The following example shows how to perform a data check for addresses 0010 to 0015 (hex).
1. Send the WRITE WITH ERROR
CORRECTION (QR) command.
Command:
QWSTH10010313233343536*[CR]
2. Write data is written to addresses 0010 to
0015 (hex). The RF Tag memory check code
and a 5-byte error correction code are written
to addresses 0016 to 001A (hex).
3. Send the READ WITH ERROR
CORRECTION (QW) command.
Command: QRSTH100100006*[CR]
Response When Read Data Is Correct:
QR0010313233343536*[CR]
Response When a 2-bit or Longer Memory
Error Is Detected:
QR76*[CR]
Response When a 1-bit Memory Error Is
Corrected:
QR7710313233343536*[CR]
Address
0000
H
Memory check code (leftmost)
Memory check code (rightmost)
Error correction code (leftmost)
Error correction code (mid)
Error correction code (rightmost)
0001
H
Area start
address
Area end
address
Error correction
code calculation
area
Memory check
code calculation
area
Address (hex)
0010
31
32
33
34
35
36
FD
11
00
0C
3C
Memory check code (leftmost)
Memory check code (rightmost)
Memory check code (leftmost)
Memory check code (mid)
Memory check code (rightmost)
0011
0012
0013
0014
0015
0016
0017
0018
0019
001A
Memory check code
Calculation area
Write data
)
(
