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Write Protection
5-5
Write Protection
5-5-1
EEPROM (Battery-free) Data Carriers
Setting Write Protection
Write Protection Settings
Example for Data Carrier
with a Memory Capacity of
254 Bytes
The write protection function is provided so that product model numbers and
other important product information stored in the Data Carrier can be pro-
tected from being lost though careless write operations. We recommend that
write protection be set after important data has been written.
If the write protection end address is written to address 0000 (hex) of the Data
Carrier, address 0001 (hex) to the specified end address will be write-pro-
tected. Write protection can be enabled and disabled by setting bit 7 of
address 0000 (hex).
Address
0000
• Write Protection Bit
Address 0000 (hex), bit 7
1
0
• Write Protection Setting Range
Address
Start address
End address
Note
1. Address 00 (hex) cannot be write-protected.
2. Addresses 80 (hex) to FD (hex) cannot be set as the end address.
3. If the end address is set to 00 (hex), all addressed from address 01 (hex)
to FF (hex) will be write-protected.
4. Write any data to be write-protected starting at address 0001 (hex). The
start address for write protection is 0001 (hex) fixed.
The following settings will write-protect addresses 0001 (hex) to 0012 (hex).
Address
0000
7
6
5
Pro-
End address
tected
/Not
pro-
tected
Enable write protection.
Disable write protection.
Write protection setting range
Always 01 (hex)
00 (hex), or 01 (hex) to 7F (hex)
7
6
5
1
0
0
9
Address (hex)
0000
0001
0012
00FD
Section 5-5
Bit No.
4
3
2
1
Description
Bit No.
4
3
2
1
1
0
0
1
2
Write-protected
area
0
0
0
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