R
EM4150
EM4350
Block Diagram
ROM
Serial Data
Encoder
Modulator
EEPROM
+V
Voltage
Regulation
VDD
Coil 2
Cr
AC/DC
converte
r
Power
Control
Cs
Coil 1
Reset
GND
Write Enable
Clock
Extractor
Sequencer
Control
Logic
Command
Decoder
Data
Extractor
Fig. 4
Functional Description
General
Memory Organisation
The 1024 bit EEPROM is organised in 32 words of 32
bits. The first three words are assigned to the Password,
the Protection word, and the Control word. In order to
write one of these three words, it is necessary to send
the valid password. At fabrication, the EM4150 comes
with all bits of the password programmed to a logic "0".
The Password cannot be read out. The memory contains
two extra words of Laser ROM. These words are laser
programmed during fabrication for every chip, are unique
and cannot be altered.
The EM4150 is supplied by means of an electromagnetic
field induced on the attached coil. The AC voltage is
rectified in order to provide a DC internal supply voltage.
When the DC voltage crosses the Power-On level, the
chip enters the Standard Read Mode and sends data
continuously. The data to be sent in this mode is user
defined by storing the first and last addresses to be
output. When the last address is sent, the chip will
continue with the first address until the transceiver sends
a request. In the read mode, a Listen Window (LIW) is
generated before each word. During this time, the
EM4150 will turn to the Receive Mode (RM) if it receives
a valid RM pattern. The chip then expects a valid
command.
Memory Map
Bit 0
Bit 31
EE
EE
PASSWORD
PROTECTION WORD
CONTROL WORD
Word 0
1
2
Mode of Operation
EE
EE
928 Bits of USER
EEPROM
Power-On
31
32
33
DEVICE SERIAL NUMBER
DEVICE IDENTIFICATION
Laser
Laser
Init
Get Command
Standard
Read Mode
Control Word
Protection Word
0 - 7 First Word Read
8 - 15 Last Word Read
16 Password Check On/Off
17 Read After Write On/Off
18 - 31 User available
0 -
7
First Word Read Protected
8 - 15 Last Word Read Protected
16 - 23 First Word Write Inhibited
24 - 31 Last Word Write Inhibited
Execute Command
Receive
Mode
request ?
Login
Yes
No
Write Word
Write Password
Selective Read
Reset
Password
Write Only - NO Read Access
Device Identification Word &
Serial Number Word
Laser Programmed - Read Only
Send word
On means bit set to logic '1'
Off means bit set to logic '0'
Fig. 6
Fig. 5
4
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