at88rf256-12 ATMEL Corporation, at88rf256-12 Datasheet - Page 3

• Manufacturer Part Number: at88rf256-12
• Description: 125 Khz Rfid Transponder Chip
• Manufacturer: ATMEL Corporation

Memory Map
The EEPROM is composed of 10 pages of 32 bits each for
a total of 320 bits. Pages 0-6 are user pages which include
ID information and other user defined bytes. Pages 0 and 7
contain the serial number, however, the copy of the serial
Commands
The explicit commands implemented in this tag permit the
reader/writer to directly access individual 32-bit pages
within the memory array, prevent future writing of particular
For the “Read” and all four “Write” commands, the data
stored within the corresponding page of the EEPROM to
the accessed page is repeatedly transmitted back to the
reader by the chip after the command has completed. This
permits a verify function for the commands. For the “Write
Lock” and “Write Configuration” commands, the entire con-
tents of page 8 are transmitted. Between each 32 bits
transmitted, there is a listening window of 8 bit times to syn-
chronize the reader and/or to permit the reader to issue a
new command to the chip.
After the “Check Password” command, the chip goes back
to the ID transmission loop and the reader/writer can issue
Page 0
Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
0 A
0 A
0 0 0 0 1 1
0 1 0 0 1 1
0 0 0 1 1 1
0 1 1 0 0 0
0 1 1 1 0 0
2
2
A
A
1
1
A
Byte 3
First ID Byte
Fifth ID Byte/User Data
ID/User Data
ID/User Data
ID/User Data
User Data
User Data
First Byte Serial #
LOCK7…LOCK0
First Byte Password
A
0
0
1 0
0 1
Write 32-bit Page A A A (followed by 32 bits of data and 1 bit of parity)
Read 32-bit Page A A A (followed by 32 bits of data)
Write Lock Byte (followed by 8 bits of data, 24 bits of 0101… and parity)
Write Configuration Bits (followed by 8 bits of 0101, 24 bits of data and parity)
Write Password (followed by 32 bits of data and 1 bit of parity)
Disable (Stop) Chip Until Power Down
Check Password (followed by 32 bits of data and 1 bit of parity)
Byte 2
Second ID Byte
Sixth ID Byte/User Data
ID/User Data
ID/User Data
ID/User Data
User Data
User Data
Second Byte Serial #
PU_LEN…RANDOM
Second Byte Password
number in page 0 can be changed at will. Page 8 is the
configuration page, which includes the lock and option bits.
Page 9 is the password page.
pages (locking), temporarily disable the chip or check a
password value and are encoded as follows:
its commands during the first listening window. After the
“Disable” command, the chip is held in reset until power is
removed.
There are a number of features that are used to prevent the
inadvertent writing of the chip. The proper command code
plus the proper Manchester data encoding must be sent to
the chip. If either an illegal code or improper encoding is
detected, the command is aborted. There is a single parity
bit sent after the command and data string (see Parity
section on page 2 for details), which must also be correct.
Third Byte Serial #
Third Byte Password
Byte 1
Third ID Byte
Seventh ID Byte/User Data
ID/User Data
ID/User Data
ID/User Data
User Data
User Data
TST_EN…TCLK_GEN
Byte 0
ID/User Data
ID/User Data
ID/User Data
Fourth Byte Serial #
RCLK_G…CONFIG_LCK
Fourth Byte Password
Fourth ID Byte
Eighth ID Byte/User Data
User Data
User Data
3