EM4170
Timing Characteristics
Parameter
Symbol Conditions
Min.
Typ.
Max.
Unit
Power on Reset Time
tpor
600
µs
Read Bit Period
LIW/ACK/NACK pattern
Duration
trdb
32
periods
tpatt
trID
160
periods
periods
Duration of ID
1536
Divergency-Time
Tdiv
224
periods
Authentication-Time
WRITE Access Time
EEPROM write time
WRITE Access Time of
the Lock Bits
tauth
4224
128
periods
periods
periods
periods
twa
twee
3072
672
twalb
VDD=3V
RF periods represent periods of the carrier frequency emitted by the transceiver unit. For example, if 125kHz is used,
the Read bit period would be: 1/125'000*32 = 256µs.
Memory Organisation
Functional Description
The 256 bits EEPROM are organised in 16 words of 16
bits. Words 0 and 1 contain the USER_MEMORY_1 and
the Lock-Bits LB1 and LB0. Words 12, 13, 14 and 15
contain the USER_MEMORY_2. Write-Mode can only be
entered if LB0 = "0" (LB1= "X").
The EM4170 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 will enter the Standby Mode and expect commands.
In Standby Mode a continuous sequence of Listen
Windows (LIW) is generated. During this time, the
crypto-Chip will turn to the Receive Mode (RM) if it
receives a valid RM pattern. The chip then expects a
command to enter the desired mode of operation.
Words 2 and 3 contain the ID that can never be modified.
Words 4 through 9 contain the 96 bits of secret key.
These bits influence the crypto-algorithm but cannot be
read directly. Words 11 and 12 contain the 32 bits of PIN-
Code. These two words can be written when the lock bits
are in unlocked state. They cannot be read out as for the
secret key.
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