User's Manual

MPR series User’s Manual: Draft version 0.95 11/4/04 page 41
1.6.7.2 Tag Commands
1.6.7.2.1 Class0 Inventory (11
h
)
Returns a list of all Class0 tags found in the field of the reader.
Request Packet
Opcode
0x11
Command Data
Antenna
1 byte
0x00: Ant A
0x01: Ant B
RF Power Level
1 byte
0x01 (min) – 0xFF (max)
Singulation
(Negotiation
Page) Field
1 byte
0x00 (ID0)
0x01 (ID1)
0x02 (ID2)
Filter Bit Count
1 byte
0-64 or 0-96
Filter Bits
0-12 bytes
Tag ID filter bits are left justified in bytes, MSByte sent first
Note: If the RF power level is 0, a Zero Power Error (0xF3) is returned.
Note: Filter bits must be left justified within the field. The least significant bits of the LSB might not be
filled.
Note: Singulation Fields ID0 & ID1 are not implemented yet.
The response is composed of one or more packets. The non-final packets will have a Status Byte of 0x01
(In Progress) and will contain TagIDs. The final packet will contain an inventory summary, and a Status
Byte of 0x00.
Non-final Response Packet
Status
0x01 (In Progress)
Number of TagIDs in Packet
1 byte
TagID
8 or 12 bytes
…
…
TagID
8 or 12 bytes
TagID is returned MSByte first. The first byte of the TagID encodes the EPCglobal tag type. This must be
used to determine the tag length. EPC-64 tags return 8 bytes, EPC-96 return 12 bytes. The two highest
order bits for EPC-96 are 0b00, all other values indicate an EPC-64 tag.
The final response packet contains an inventory summary.
Final Response Packet
Status
0x00 (Complete)
Total Tags reported
2 bytes
Under-run error count
2 bytes
Tag CRC error count
2 bytes