CR14 STMicroelectronics, CR14 Datasheet - Page 28

• Manufacturer Part Number: CR14
• Description: Low Cost Iso14443 Type-b Contactless Coupler Chip With Anti-collision And Crc Management
• Manufacturer: STMicroelectronics

6 CR14 ISO14443 type-B Radio Frequency data transfer
6.4
6.5
Figure 23. Wave Received using BPSK Sub-carrier Modulation
28/46
1/847kHz
V RFIN
Request End Of Frame
The End Of Frame (EOF) shown in
Figure 22. Request End Of Frame
Input RF Data Transfer from the PICC to the CR14 (Answer
Frame)
The CR14 uses the ISO14443 type-B retro-modulation scheme which is demodulated and
decoded by the RF
The modulation is obtained by modifying the PICC current consumption (load modulation). This
load modulation induces an H-field variation, by coupling, that is detected by the CR14 RF
input as a voltage variation on the antenna. The RF
decodes the information received from the PICC.
Data must be transmitted using a 847kHz, BPSK modulated sub-carrier frequency, f
shown in
(from ‘0’ to ‘1’ or from ‘1’ to ‘0’) are encoded by phase shift keying the sub-carrier.
a falling edge,
followed by ten Elementary Time Units (ETU) containing each a logical ‘0’,
followed by a single rising edge.
Figure
ETU
23, and as specified in ISO14443 type-B. In BPSK, all data state transitions
IN
circuitry.
b 0
0
b 1
0
phase shift
1/106kHz
b 2
0
Figure 22
b 3
0
b 4
0
consists of:
b 5
0
V OFFSET
IN
b 6
0
V
input demodulates this variation and
RET
b 7
0
b 8
0
V DYN
b 9
0
PICC data bit to be transmitted
to the CR14.
847kHz BPSK, resulting signal
generated by the PICC for the
load modulation.
t
Load modulation effect on
the H-Field received on the
CR14 RF IN input pad
ai09252
S
, as
ai12051
CR14
IN