XRA00 Datasheet, PDF (22/40 Pages) STMicroelectronics – UHF, EPCglobal, Contactless Memory IC 96 bit ePC with Inventory and Kill Function

XRA00
READER COMMAND STRUCTURE - (REQUEST FRAME COMMAND FORMAT)
The format of a basic command from the Reader
to the XRA00 is composed of 7 fields and 5 pieces
of parity information as shown below:
[SPINUP][SOF][CMD][P1][PTR][P2][LEN][P3]
[VALUE][P4][P5][EOF]
The Reader transmits the SPINUP field first, and
the EOF field is transmitted last. Within each field,
the LSB is transmitted first. The field definitions
are given in Table 5.
Programming commands have the same format
as basic commands (see Table 5.), except for a
few additional pulses (see Figure 34.) for an exam-
ple of a programming command).
Table 5. Request Frame Command Field Definitions
Command Number
Field
of bits
Field Description
[SPINUP]
Every Basic command is prefixed by a series of logical zeros (‘0’) for XRA00 timing. The
20 synchronization circuitry on the XRA00 uses this part of the message to establish its onboard
timing for reading/decoding messages and clocking subsequent replies to the Reader.
[SOF]
1
Start of Frame indicator. A logical one (‘1’)
[CMD]
8-bit field that specifies the command being sent to the XRA00 devices. (See Basic
8
Command Encoding below.) With 8 bits there could be up to 256 commands. The XRA00
command set only has six commands, the remaining address space is reserved.
[P_1]
1
Odd Parity of the [CMD] field data.
[PTR]
8-bits - Pointer to a location (or bit index) in the XRA00 address range. The bit index starts at
8
the LSB and works up. [PTR] is the starting point for XRA00 devices to attempt a match with
data specified in the [VALUE] field. (Defined below.) The [PTR] field ranges from 0 to 255.
[P2]
1
Odd Parity of the [PTR] field data.
[LEN]
8
8-bits - Equal to the length of the data being sent in the [VALUE] field. (Defined below). The
[LEN] Field is always greater than zero.
[P3]
1
Odd Parity of the [LEN] field data.
[VALUE]
Variable
1 to 96 bits of data for XRA00 devices. In PingID, ScrollID, Quiet, or Kill commands, this is the
data that the XRA00 will attempt to match against its own address. The first bit received by
the XRA00 in the [VALUE] field will be compared to the XRA00 memory at the location
contained in the [PTR] field.
[P4]
1
Odd Parity of the [VALUE] field data.
[P5]
1
Odd Parity of all of the Parity fields.
[EOF]
1
End of Frame indicator. A logical one (‘1’).
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