EM4450

EM4550

Copyright

 2003, EM Microelectronic-Marin SA

6

www.emmicroelectronic.com

Read Sequence

POR

OUTPUT

LIW

D0-D7 P0 D8-D15 P1 D16-D23 P2 D24-D31 P3 PC0-PC7 "0"

T0 = Period of RF carrier

frequency

INIT

LIW

FWR

LIW FWR+1

LWR LIW

FWR

LIW

LIW

LIW

Coded Data

Data

1 bit = 64 T0 periods (Opt64)

32 T0 periods (Opt32)

T0 periods :

32 32

128

64

64

(Opt64)

16 16

64

32

32

(Opt32)

1 bit

1 bit

1 bit

1 bit

Fig. 7

Receive Mode

To activate the Receive Mode, the Transceiver sends to the chip the RM pattern (while in the modulated phase of a Listen

Window LIW). The EM4450/4550 will stop sending data upon reception of a valid RM. The chip then expects a command.

The RM pattern consists of 2 bits "0" sent by the transceiver. The first bit "0" transmitted is to be detected during the 64 (32

opt 32) periods where the modulation is "ON" in LIW.

Fig. 8

Commands

The commands are composed of nine bits : eight data bits and one even parity bit (total amount of "ones" is even including

the parity bit).

Fig. 9

WORD n

LIW

RM COMMAND

output

input

COM M AND BITS

FUNCTION

0 0 0 0 0 0 0 1 1

LOGIN

0 0 0 1 0 0 0 1 0

WRITE PASSWORD

0 0 0 1 0 0 1 0 0

WRITE WORD

0 0 0 0 1 0 1 0 0

SELECTIVE READ MODE

1 0 0 0 0 0 0 0 1

RESET

First bit Received

Parity bit