Avery Dennison RFID - Manual (Page 29)

HowToRFID
Revision: 13 Date: 31 August 2009
Page 29 of 53
Field
[data type ID] Contents / function Size in Bits (Bytes) Read / Write
access
User data [0] − also called user memory
− is organized in blocks of 2 bytes
−
size varies (depending from chip type) from 0 to X
0
224 (28): NXP G2
512 (64): NXP G2XM Read / Write
Kill password [3] − this password must be referenced when using “Kill tag”
command
− must be 4 bytes
− is defined in [EPC3]
32 (4) Write only
Access password
[4] − this password must be used to authorize certain access to
tag memory e.g. locking and unlocking memory
− must be 4 bytes
− is defined in [EPC3]
32 (4) Write only
Memory bank(s)
[5] −
a memory bank presents the physical memory area of a
tag
− banks are defined as follows:
− 0: Access + Kill password
− 1: EPC
−
2: TID
− 3: User data
Direct access to a memory bank is depreciated since behavior
is undefined (behavior depends from size of memory bank
areas of different tags and additionally depends from RFID
reader firmware module.
A direct read or write access to a memory bank should only be
considered if there is no direct way to access a specific
information
Note: some memory banks may be unreadable due to security
restrictions
Vary in size Read only
AFI [6] −
AFI = Application Family Identifier
− is a part of PC (Protocol Control) bits in the EPC memory
bank (but not part of the EPC itself)
− possible range for values: 0..511 (0x00 … 0x1FF) where
the MSB is used as identifier for a not EPC global defined
identifier, and bits to lower 8 bits are named “NSI”
(Numbering System Identifier)
− is defined in [EPC3] for UHF technology
−
9 (2)
Read / Write
Memory Block [7] −
There is no field “memory block” in EPC Gen 2
transponders!
− This field-identifier is only a helper to allow EasyPlug
commands the addressing of any memory area inside the
transponders memory without being limited to the
predefined field identifiers.
− see EasyPlug command description for details
varying Read / (Write)
Table 12 – Data fields of UHF / EPC Gen 2 tags