Commands
7-49
697 Set User-Programmable Group Select Equals (GSE)
Filter
Command #697 assigns the user-programmable GSE filter.
The command string is assigned according to the following format:
697 MM AA DDDDDDDDDDDDDDDD
where
MM = The tag uses this mask to determine which of the eight Comparison Data bytes
are to be compared for the Group Select filter.
AA = This field is used by the tag to determine the start address in the tag memory for
the comparison data.
DD…DD = Comparison Data: an 8-byte field (16 characters) used by the tag as the
comparison data for the Group Select filter. The tag compares the data in this field to
data in tag memory beginning at the Start Address to determine if the tag will respond
to a reader Group Select request. Only the bytes having the corresponding bit set in the
GSE Mask is used for this comparison.
As an example, to configure a reader to have only tags with data in byte locations 10,
12, and 15 (decimal) with hexadecimal values “00,” “01,” and “02,” the following
command is used:
#697 A4 0A 0005014202024133
To understand how the data is interpreted, it is necessary to break down the GSE Mask
field, A4, into binary:
A4 = 1010 0100
This mask equates to the tag comparing the first, third, and sixth bytes of the Compar-
ison Data to data in the tag beginning at address location 0A (10 decimal).
The Comparison Data field is broken down in bytes with the bytes corresponding to
the mask underlined in bold (for clarification):
Address: 0A 0B 0C 0D 0E 0F 10 11
Data: 00 05 01 42 02 02 41 33
where
0A (10 decimal) must be equal to “00” hexadecimal, the first byte in the Comparison
Data field
0C (12 decimal) must be equal to “01” hexadecimal, the third byte in the Comparison
Data field
0F (15 decimal) must be equal to “02” hexadecimal, the sixth byte in the Comparison
Data field
Reader response:
Done
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