R
EM4150
EM4350
Standard Read Mode
Receive Mode
After a Power-On Reset and upon completion of a
command, the chip will execute the Standard Read
Mode, in which it will send data continuously, word by
word from the memory section defined between the First
Word Read (FWR) and Last Word Read (LWR). When
the last word is output, the chip will continue with the first
word until the transceiver sends a request. If FWR and
LWR are the same, the same word will be sent
repetitively. The Listen Window (LIW) is generated
before each word to check if the transceiver is sending
data. The LIW has a duration of 320 (160 opt 32) periods
of the RF field. FWR and LWR have to be programmed
as valid addresses (FWR ≤ LWR and ≤ 33).
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 EM4150 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
WORD n
LIW
INPUT
RM COMMAND
The words sent by the EM4150 comprise 32 data bits
and parity bits. The parity bits are not stored in the
EEPROM, but generated while the message is sent as
described below. The parity is even for rows and
columns, meaning that the total number of "1's" is even
(including the parity bit).
RM : Two Consecutive bits set to logic "0"
Fig. 9
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).
Word Organisation (Words 0 to 32)
First bit output
Data
Row Even Parity
COMMAND BITS
FUNCTION
D0
D8
D1
D2
D3
D4
D5
D6
D7
P0
LOGIN
0 0 0 0 0 0 0 1
0 0 0 1 0 0 0 1
0 0 0 1 0 0 1 0
0 0 0 0 1 0 1 0
1 0 0 0 0 0 0 0
1
0
0
0
1
D9 D10 D11 D12 D13 D14 D15 P1
D16 D17 D18 D19 D20 D21 D22 D23 P2
D24 D25 D26 D27 D28 D29 D30 D31 P3
PC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7
WRITE PASSWORD
WRITE WORD
0
Column Even Parity
Last bit output
logic "0"
SELECTIVE READ MODE
RESET
Fig. 7a
When a word is read protected, the output will consist of
45 bits set to logic "0". The password has to be used to
output correctly a read protected memory area.
Word Organisation (Word 33)
First bit
Received
C0
ID2 ID3 ID4 ID5 ID6 ID7 ID8 ID9 P1
R0 R1 R2 R3 R4 R5 R6 R7 P2
CK0 CK1 CK2 CK3 CK4 CK5 CK6 CK7 P3
C1
C2
C3
C4
C5 ID0 ID1 P0
Parity bit
PC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7
0
Fig. 10
Selective Read Mode
C0 - C5
ID0 - ID9
: P4150 Code set to Hexadecimal 32
: Version Code
The Selective Read Mode is used to read other data than
that defined between FWR and LWR. To enter Selective
Read Mode, the Transceiver has to send during LIW a
Receive mode pattern (RM) to turn the EM4150 in
Receive Mode. Then the Selective Read Mode
Command is sent by the transceiver followed by the First
and Last addresses to be read. The FWR and LWR are
then replaced by the new addresses and the chip is
operating in the same way as the Standard Read Mode.
The control word is not modified by this command, and
the next standard read mode operation will work with
original FWR and LWR (Selected area is read once and
then the chip returns to Standard Read Mode).
R0 - R7 / CK0 - CK7 : EM reserved, and Check bits
Fig. 7b
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"
To read words which are Read Protected, a Login
command has to be sent by the transceiver prior to the
Selective Read command. The Login command is to be
used only once for all subsequent commands requiring a
password.
1 bit - 64 T0 periods (Opt64)
32 T0 periods (Opt32)
T0 periods :
32 32
128
64
32
64 (Opt64)
32 (Opt32)
Data
16 16
64
Coded Data
T0 = Period of RF carrier frequency
Fig. 8
5
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