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"
T0 periods :
32 32
128
16 16
64
1 bit = 64 T0 periods (Opt64)
32 T0 periods (Opt32)
64
32
64
32
(Opt64)
(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
00000001
00010001
00010010
00001010
10000000
First bit Received
1
0
0
0
1
FUNCTION
LOGIN
WRITE PASSWORD
WRITE WORD
SELECTIVE READ MODE
RESET
Parity bit
Fig. 9
Copyright
2003, EM Microelectronic-Marin SA
6
www.emmicroelectronic.com
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
