Setup Guide

"K" – Kill, Lock, Access Descriptors
"K" – Kill, Lock, Access Descriptors
K[<SUBCMD>[<PARAMS>]]
The K family of commands are used to control lock kill and access command behavior. The K
commands allow the user to get/set passwords used in kill, lock and access operation and
specify lock type for the lock commands.
The Kill, Lock and Access commands are described in detail in the EPC Global C1G2
specification: uhf c1g2_standard- version 1.2.0.pdf
Locking
Locking is one of the more complex activities performed under the Gen2 protocol. As
mentioned above, tag memory is divided into different regions or “Banks”. Tag memory may be
“locked” where it can only be changed using an access password, or “perma-locked” where it
cannot ever be changed again. (Other options, like “perma-unlock” are also available).
EPC, TID and User memory are always readable under standard Gen2 – even when those
regions are locked. In contrast, Reserved memory, where the Kill and Access passwords are
stored, can only be read with the correct access password after that section has been locked.
To lock or unlock a tag, first one must have a tag programmed with a non-zero access
password written into the correct region of Reserved memory. Then, a Lock command may be
issued with a data field representing which region(s) of memory to lock and what type of lock
to use (regular or “perma” lock). The data field is a mask, where bits represent memory
locations and lock types. (more below).
The following options are available for locking:
• Read Unlocked – there is unrestricted access to read from this memory
• Read Locked – the memory cannot be accessed for reading without using a
password
• Write Locked – the memory cannot be accessed for writing without using a
password
• Read Permanently Unlocked – there is unrestricted access to read from this
memory and this memory can never be locked
• Write Permanently Unlocked – this memory cannot be accessed for writing
without a password and this memory can never be locked
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