xra00 STMicroelectronics, xra00 Datasheet - Page 7

• Manufacturer Part Number: xra00
• Description: Uhf, Epcglobal Class 1b, Contactless Memory Chip 96 Bit Epc With Inventory And Kill Function
• Manufacturer: STMicroelectronics

Symbol Transmission Format for Request
Frame
Modulation of negative pulse width (RF interrup-
tion period) is used for data transmission and syn-
chronization to XRA00s. Four timings are
distinguished by their shortness. Their symbols
are as follows:
Each symbol is referenced to the Master Clock
Time Period, t
during the Request Frame header modulation. t
the bit duration period generated by the Reader.
Request Binary Data "0"
Data Modulation Timing, t
XRA00 clocking when data = "0", is encoded by a
"narrow" 1/8t
is also used during data synchronization at the be-
gining of each Request Frame. t
in
Request Binary Data "1"
Data Modulation Timing, t
XRA00 clocking when data = "1", is encoded by a
"wide" 3/8t
also used for SOF (Start Of Frame) and EOF (End
Of Frame) symbols within the Request Frame.
t
Figure 6. Data Modulation Timing - “0”
Figure 7. Data Modulation Timing - “1”
fwhm1
Clock Low
Clock Low
(Data '1')
(Data '0')
Figure 6.
t
t
t
t
fwhm0
fwhm1
fwhmBin
trangap
is illustrated in
: encode binary data "0"
: encode binary data “1”
0
: encode Transaction Gap pulse
: encode Bin synchroniZation pulse
pulse width modulation. This timing is
0
'0'
pulse width modulation. This timing
0
, which is defined by the Reader
t
fwhm1
t fwhm0 = 1/8t 0
'1'
Figure 7.
= 3/8t
0
fwhm0
fwhm1
fwhm0
, for Reader-to-
, for Reader-to-
is illustrated
t
t 0
0
0
is
Bin pulse and Bin Response Window
XRA00 Answer Frames are synchronized by the
Reader using Bin pulse modulation. The Bin pulse
is encoded by a 3/8t
Bin pulse is also used to define the Bin Response
Window time slots during the inventory sequence
after a PINGID command is issued. The Bin Re-
sponse Window is shown in
Transaction Gap
During communication with XRA00, each Request
Frame begins with a transaction gap, t
lowed by a period of time, t
the carrier frequency is unmodulated (See
9.
t
Window.
Power Up
If during communication with the Reader the carri-
er is turned off for a time exceeding
loses DC power. After XRA00 is powered up
again, a minimum time of t
the carrier frequency is unmodulated, must pre-
cede the Data Modulation Window. (See
10.
t
transetup
transetup
for an illustration and
for an illustration and
). t
.)
transetup
precedes the Data Modulation
0
pulse width modulation.The
'0'
Table 2.
Table 2.
transetup
transetup
Figure 8.
'1'
for the value of
for the value of
, during which
, during which
t
Reset ,
trangap
XRA00
XRA00
Figure
Figure
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