EM4170

Copyright

 2002, EM Microelectronic-Marin SA

4

www.emmicroelectronic.com

Timing Characteristics

Parameter

Symbol

Conditions

Min.

Typ.

Max.

Unit

Power on Reset Time

Read Bit Period

LIW/ACK/NACK pattern

Duration

Duration of ID

Divergency-Time

Authentication-Time

WRITE Access Time

EEPROM write time

WRITE Access Time of

the Lock Bits

32

160

1536

224

4224

128

3072

672

600

µs

periods

periods

periods

periods

periods

periods

periods

periods

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.

Functional Description

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.

Memory Organisation

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").

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.