User Guide

Multi-Protocol Tag Commands
58
Clear Tag Buffer (2Ah)
The Clear Tag Buffer command resets the tag buffer. This clears the buffer of any
current tags and reset the read index to 0. A Multi-Protocol Tag Read or Read Tag
Multiple command must be issued to load new tags into the buffer.
If Clear Tag Buffer or Get Tag Buffer is not used after a Multi-Protocol Tag Read to
remove all tags, old tags will be left in the buffer. This means that if tags that have not
been removed from the buffer are read again they will not be added to the buffer as
second time, only their Read Count will be incremented.
Multi-Protocol Tag Read (2Fh)
The Multi-Protocol Tag Read command allows tag reading and inventorying commands to
be performed on tags with different protocols at the same time, using a single command.
This command contains the following request fields:
Multi-Protocol Tag Read Request Fields
FF 00 2A 1D 25
SOH Length OpCode CRC
Field Value Description
TM OpCode 0x2F TM OpCode indicating a multi-protocol opera-
tion.
Timeout [2 bytes] Indicates how long the entire command
should spend attempting the operation, in mil-
liseconds. When TM Option=0x00 the time
gets divided equally across each protocol
specified.
TM Options • 0x00 = Basic Multi-protocol search.
Uses Protocol Bitmask
Indicates the operation to perform and addi-
tional fields that will be required.
Command Opcode • 0x00 - reserved
• 0x21 - tag read single
• 0x22 - tag read multiple
Indicates the command that will be performed
for each protocol specified.
Note: Allegro/Title-21 is not supported
with tag read multiple.
Note: Allegro/Title-21 uses Read Request
(28h; C003h) for tag read single.