User's Manual

Tag Programming
55
Programming the ISO18000-6A Tag
Both the Wa and Wt command can be used with the ISO18000-6A tag. In addition
to Wa and Wt, two additional commands can modify specific data in the tag. The
Wd command modifies the DSFID and Wf modifies the AFI.
Typically, the Wt command is used to modify user data in the tag. The Wt, Wd, and
Wf commands require the tag ID to be in the d: parameter. Also, the tag must first
be put in the SELECT state using the Ts command with the tag ID specified in the
d: parameter.
NOTE: Some varieties of ISO18000-6A tags are not writeable. Currently, only Atmel
markets a writeable ISO18000-6A tag.
The following parameters are used with the Wa or Wt commands.
• a: address block (in Hex). In ISO18000-6A, only a single block can be written
at one time and this parameter represents the specific four byte block.
• l: length. This parameter is optional since each write operation must contain
exactly four bytes.
• b: write data. This parameter must contain four bytes of data.
The following is a typical command to write to an ISO18000-6A tag:
}wa,a:0,b:01020304!
For example, to write AABBCCDD to address 0x20 on a tag with ID
E00300001122334455667788, issue the following command:
}wt,d:E00300001122334455667788,a:20,b:AABBCCDD!
In addition to the Wa, Wt, Wd, and Wf commands, SAMSys readers also support
the following EPC1 operations:
• Lb Lock Block
• Yl Query Lock Status (returns
f:0 for unlocked or f:1 for locked)
Each of these operations must specify a particular tag ID using the d: parameter or
first be put in the SELECT state using the Ts command with tag ID specified in
the d: parameter.