CR14 datasheet(28/46 Pages) STMICROELECTRONICS

28 / 46 page

6 CR14 ISO14443 type-B Radio Frequency data transfer

CR14

28/46

6.4

Request End Of Frame

The End Of Frame (EOF) shown in Figure 22 consists of:

●

a falling edge,

●

followed by ten Elementary Time Units (ETU) containing each a logical ‘0’,

●

followed by a single rising edge.

Figure 22. Request End Of Frame

6.5

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 RFIN circuitry.

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 RFIN

input as a voltage variation on the antenna. The RFIN input demodulates this variation and

decodes the information received from the PICC.

Data must be transmitted using a 847kHz, BPSK modulated sub-carrier frequency, fS, as

shown in Figure 23, and as specified in ISO14443 type-B. In BPSK, all data state transitions

(from ‘0’ to ‘1’ or from ‘1’ to ‘0’) are encoded by phase shift keying the sub-carrier.

Figure 23. Wave Received using BPSK Sub-carrier Modulation

ETU

0000000000

ai09252

VDYN

VRFIN

VOFFSET

1/106kHz

1/847kHz

phase shift

VRET

Load modulation effect on

the H-Field received on the

CR14 RFIN input pad

PICC data bit to be transmitted

to the CR14.

847kHz BPSK, resulting signal

generated by the PICC for the

load modulation.

ai12051

CR14 데이터시트(PDF) 28 Page - STMicroelectronics

CR14 데이터시트(HTML) 28 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

데이터시트 다운로드

링크 URL