lri2k STMicroelectronics, lri2k Datasheet - Page 39

• Manufacturer Part Number: lri2k
• Description: 13.56 Mhz, 2048-bit Eeprom Tag Ic With 64-bit Uid And Kill Code, Iso 15693 And Iso 18000-3 Mode 1 Compliant
• Manufacturer: STMicroelectronics

LRI2K
15
15.1
Anticollision
The purpose of the anticollision sequence is to inventory the LRI2Ks present in the VCD
field using their unique ID (UID).
The VCD is the master of communications with one or several LRI2Ks. It initiates LRI2K
communication by issuing the Inventory request.
The LRI2K sends its response in the determined slot or does not respond.
Request parameters
When issuing the Inventory command, the VCD:
The Mask Length is the number of significant bits of the Mask Value.
The Mask Value is contained in an integer number of bytes. The Mask Length indicates the
number of significant bits. The LSB is transmitted first.
If the Mask Length is not a multiple of 8 (bits), as many 0-bits as required will be added to
the Mask Value MSB so that the Mask Value is contained in an integer number of bytes.
The next field starts on the next byte boundary.
Table 17.
In the example of
to the Mask Value MSB. The 11-bit Mask and the current slot number are compared to the
UID.
Table 18.
MSB
(b
SOF
15
) MSB
sets the Nb_slots_flag as desired,
adds the Mask Length and the Mask Value after the Command Field,
Request_
0-bits added
8 bits
flags
0000 0
Inventory request format
Example of the addition of 0-bits to an 11-bit mask value
Table 18
Command Optional AFI
8 bits
and
Figure
8 bits
39, the Mask Length is 11 bits. Five 0-bits are added
length
Mask
8 bits
11-bit Mask Value
100 1100 1111
0 to 8 bytes
Mask value
16 bits
CRC
Anticollision
LSB (b
EOF
39/89
LSB
0
)