EM4450
EM4550
Read Sequence
POR
INIT
OUTPUT
LIW LIW
FWR
LIW FWR+1
LWR LIW LIW
FWR
LIW
LIW D0-D7 P0 D8-D15 P1 D16-D23 P2 D24-D31 P3 PC0-PC7 "0"
1 bit = 64 T0 periods (Opt64)
32 T0 periods (Opt32)
T0 periods :
32 32
16 16
128
64
64
32
64 (Opt64)
32 (Opt32)
Data
Coded Data
T0 = Period of RF carrier
frequency
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.
output
input
WORD n LIW
RM COMMAND
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).
COM M AND BITS
FUNCTION
0 0 0 0 0 0 0 1 1
0 0 0 1 0 0 0 1 0
0 0 0 1 0 0 1 0 0
0 0 0 0 1 0 1 0 0
1 0 0 0 0 0 0 0 1
LOGIN
WRITEPASSWORD
WRITEWORD
SELECTIVEREAD MODE
RESET
First bit Received
Parity bit
Fig. 9
6
www.emmicroelectronic.com
Copyright 2003, EM Microelectronic-Marin SA
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
