User's Manual

COBALT UHF-SERIES CHAPTER 5: COMMAND PROTOCOLS
PAGE 56 OF 140
5.4.4 ABx Fast - Multi-Tag Command Packet Structure
Multi-tag (anti-collision) commands are used to communicate with one or more RFID
tags, when numerous tags are simultaneously within RF range. ABx Fast Multi-tag
commands are formatted as follows:
COMMAND PACKET ELEMENT CONTENT SIZE
COMMAND HEADER
:
The first two bytes of an ABx Fast command.
0x02, 0x02 2 bytes
COMMAND SIZE
:
This two-byte integer defines the number of bytes in the
packet (excluding Header, Command Size and
Terminator).
0x0007 +
(number of bytes
of additional
data)
2-byte
integer
COMMAND ID:
This single-byte value indicates the RFID command to
execute.
0x06
(Write Data)
1 byte
Reserved for future use
0x00 1 byte
Reserved for future use
0x00 1 byte
TAG LIMIT:
This single byte specifies the maximum # of tags
expected in RF range, up to 100; 0x64 = 100 tags
expected max (when applicable)
0x64 1 byte
START ADDRESS
:
This two-byte integer indicates the location of tag
memory where a read or write operation shall begin.
0x0000 2-byte
integer
BLOCK SIZE
(
READ/WRITE LENGTH
):
This two-byte integer represents the number of bytes that
are to be read from or written to the RFID tag.
0x0001 2-byte
integer
TIMEOUT VALUE
:
This two-byte integer indicates the maximum length of
time for which the controller will attempt to complete the
command. Measured in milliseconds, this value can have
a range of 0x0001 to 0xFFFE or between 1 and 65,534
msecs.
0x07D0
(0x07D0 = 2000
x .001 = 2
seconds)
2-byte
integer
ADDITIONAL DATA
:
This parameter uses one byte to hold a single character
for fill operations and supports the use of multiple bytes
when several characters are needed for write commands
(when applicable).
0x00 1 or
more
bytes
COMMAND TERMINATOR
:
The single-byte command packet terminator is always
0x03 for ABx Fast.
0x03 1 byte
Table 5-9: ABx Fast - Anti-Collision Command Packet Structure