MLX90121 Просмотр технического описания (PDF) - Melexis Microelectronic Systems

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MLX90121

13.56MHz RFID Transceiver

Melexis Microelectronic Systems  

MLX90121

13.56MHz RFID Transceiver

The ISO15693 protocol, mode 1 out of 256, is implemented using three symbols. Start of frame (SOF),

end of frame (EOF) and pulses encoding result of the combination of these three symbols.

ISO15693 (1 out of 256)

ISO15693 (1 out of 256)

Symbol

Sym0

Sym1

Sym2

Code

11111111

11110000

00001111

Name

SOF

EOF

Pulse 1 to 256

Combination

Sym2+2*Sym0+Sym1

Sym0+Sym2

255*Sym0+Sym1

Note

•

The position of the symbol Sym1 encodes pulses from 1 to 256. For example: Pulse1 = Sym1 +

255*Sym0 and Pulse45 = 44*Sym0 + Sym1 + 211*Sym0.

The ISO14443 -B protocol is implemented with only two symbols. This allows fast addressing with only

one CK pulse.

ISO14443-B

Symbol

Sym0

Sym1

Name

L

H

Code

00000000

11111111

Time Reference Setup

The time reference is defined in the EncoderTimeRef register. The time reference contains the value of

one bit time. Hence Symbol _ Time = 8 * Bit _ Time

The bit time is defined by the EncTimeRef parameter. EncTimeRef is an integer value, it is calculated as

follows:

EncTime Re

f

=





Bit _ Time

1

3.39Mhz





−

1

EncTimeRef is coded on 5 bits. This means that Bit_Time_max = 9.44µs and Symbol_Time_max =

75.52µs.

ISO Examples

Norm

ISO15693 (1 out of 4)

ISO15693 (1 out of 256)

ISO14443B

Symbol

Time

75.52 µs

18.88 µs

9.44 µs

Bit

Time

9.44 µs

2.36 µs

1.18 µ

EncTimeRef

0x1F (11111)

0x07 (00111)

0x03 (00011)

3901090121

Rev. 009

Page 12 of 26

Data Sheet

Sept.-2009

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