User Guide

Gen2 Tag Commands
120
If Option=0x00 or 0x01 is used then the unused Tag Singulation Fields must be removed
from the request.
Note
If Option=00, the write tag data is performed without any select criteria
resulting the first tag found being written. In that case there is no way to
determine what tag gets written to unless there is only one tag in the RF
field.
Lock Tag (25h)
The Lock Tag command locks the specified memory bank of a tag. The tag which will be
locked can be specified using the
Tag Singulation Fields or, if Option=0x00 of the Tag
Singulation Fields is specified, it will attempt to lock the first tag it finds. If no tag is in the
field, the memory location doesn’t exist or is unlockable, or the Select criteria cannot be
satified a fault code is returned.
In addition to the Tag Singulation Fields the Lock Tag command takes several fields
which specify how the tag is to be locked. These fields are:
Lock Tag Fields
The values of the Mask and Action bits indicate how a tag is to be locked. The 10 Least
Significant Bits of each 16-bit argument are used to indicate the lock behavior for each
Field Value Description
AccessPwd 4 byes The Access Password for the tag. In order to lock a tag the
Access Password must be non-zero. To set the access pass-
word using the Write Tag Data (24h) command.
Mask Bits
1
2 bytes
The Mask bits specify which fields should be modified
according to the Actions bits. When a Mask Bit =0 the
corresponding Action bit is not applied and the current
lock setting is retained. When a Mask Bit =1 the corre-
sponding Action bit is applied and the new lock setting is
implemented.
Action Bits
1
2 bytes
The Action bits specify whether to assert or deassert a
lock behavior for the associated memory location. Action
Bits are only applied if the corresponding Mask Bits =1.
1-The Mask and Action bits correspond to the identically named fields described in Section 6.3.2.10.3.5
of the Gen2 specification.