XRA00 Datasheet, PDF (10/40 Pages) STMicroelectronics – UHF, EPCglobal, Contactless Memory IC 96 bit ePC with Inventory and Kill Function

XRA00
Table 3. Request Modulation Pulse Parameters for European Operation (−20 to 55°C)
Symbol
Description
Min
Max
F_C
UHF Carrier Frequency
860
870
t₀
Master Clock Time Period for a single bit sent to the XRA00
40
66,67
t_0Tol
Master Clock Time Period Tolerance
-1
+1
1/t₀
Request Frame Data Rate (1/T₀)
15
25
t_fwhm0
Pulse Modulation Width of Binary Data 0 at 50% Level
1/8 * T₀
t_fwhm1
Pulse Modulation Width of Binary Data 1 at 50% Level
3/8 * T₀
t_fwhmBin
Pulse Modulation Width of Bin Pulse at 50% Level
3/8 * T₀
t_trangap
Pulse Modulation Width of Transaction Gap at 50% Level
10/8 * T₀
t_fwhmBinRW Bin Response Window at 50% Level
4*T₀
8*T₀
t_transetup
Delay between Transaction Gap and Data Modulation Windows
64
t_tranhold
Delay before the next Transaction Gap
2.5*T₀ 2000
t_f
Pulse Modulation Fall Time (90% to 10% level)
300
t_r
Pulse Modulation Rise Time (10% to 90% level)
300
Ripple
Ripple
10
MOD
Pulse Modulation Depth
40
60
t_Coast
Delay between Request EOF and the next Transaction Gap
20
T_Reset
RF Off time to Power down a XRA00
200
Note: The data shown in Table 3. is Preliminary Data. It is subject to change without previous notice.
Units
MHz
µs
%
Kbps
µs
µs
µs
µs
µs
µs
µs
ns
ns
%
%
ms
µs
Request Frame Format
Readers communicate with the XRA00 using two
types of modulation: Data modulation and Bin
modulation.
Data modulation is used to transmit data from the
Reader to the XRA00.
Bin modulation is used to synchronize XRA00 an-
swers and define time slot intervals while running
the XRA00 anti-collision algorithm after a PINGID
command.
All transactions begin with a transaction gap pulse,
t_trangap, followed by a period of time at least equal
to t_transetup that precedes the Data modulation win-
dow as described in Figure 11.
During the Data modulation, the Reader provides
a master clock signal to XRA00 devices located in
its neighborhood. The time between clock pulses,
t₀, determines the Reader-to-XRA00 data rate.
The XRA00 devices are synchronized to the
Reader on the negative-going edge of the low lev-
el interval of the RF envelope. There is a propor-
tional relationship between this fundamental
frequency and all subsequent signaling.
The encoding used for the binary data from the
Reader to the XRA00 is the pulse width modula-
tion of the low level pulse as shown in Figure 12.
Logical 0 is defined as a modulation whose width
is 1/8 of the master clock interval (Figure 6.), t₀.
Logical 1 is encoded as a modulation whose width
is 3/8 of the master clock interval (Figure 7.), t₀.
After the Data modulation windows in which the
Reader generates the XRA00 command, the
Reader generates Bin pulses to define the time
slots used by the XRA00 to answer. During the
first interval, after the Data modulation EOF, the
XRA00 sets up for answers. The XRA00 uses one
out of two Bin modulation schemes depending on
the Reader command.
For SCROLL commands, the Reader generates 1
Bin pulse used for synchronization, followed by the
XRA00 answer.
For PING commands, the Reader generates 8 BIN
pulses to define 8 BIN response windows. These
8 BIN response windows are used to delineate
XRA00 answers during a PINGID command.
A BIN interval is defined by a BIN pulse with a
width of t_fwhmBin = 3/8t₀, followed by a BIN re-
sponse window delay of t_fwhmBinRW = 8T₀.
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