MLX90121

13.56MHz RFID Transceiver

3901090121

Page 12 of 26

Data Sheet

Rev. 007

Jan-2008

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

Code

Name

Combination

Sym0

Sym1

Sym2

11111111

11110000

00001111

SOF

EOF

Pulse 1 to 256

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 -A protocol is implemented using three symbols, according to the ISO specification.

ISO14443-A

Symbol

Name

Code

Sym0

Sym1

Sym2

X

Y

Z

11110011

11111111

00111111

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

one CK pulse.

ISO14443-B

Symbol

Name

Code

Sym0

Sym1

L

H

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

Time

Bit

Time

Symbol

_

*

8

_

=

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

follows:

1

39

.

3

1

_

Re

−

















=

Mhz

Time

Bit

f

EncTime

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

µs and Symbol_Time_max =

75.52

µs.