EM4170

Copyright

 2002, EM Microelectronic-Marin SA

6

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Commands

The commands are composed of 4 bits, divided into 3 data bits and 1 even parity bit (total amount of "1's" is even including

the parity bit). There exist 6 different commands. Upon reception of an unknown command or a command with wrong parity

the chip will immediately return into Standby Mode.

COMMAND BITS

FUNCTION

WRITE WORD

1 0 1 0

Parity bit

First bit

Recieved

AUTHENTICATION

0 1 1 0

ID-MODE

0 0 1 1

UM-MODE-1

0 1 0 1

Commands

SEND PIN

UM-MODE-2

1 0 0 1

1 1 1 1

Fig. 5

ID Mode

After reception of the command including the parity the chip sends a header consisting of 12 Manchester coded '1's

followed by 4 Manchester coded '0's. Then the chip sends the 32 Bits of ID contained in words 3 and 2 of the EEPROM

once without parity starting with the MSB of word 3. After completion the chip returns to Standby-Mode.

OUTPUT

Coded Data

Data

1 bit - 32 T0 periods

T0 = Period of RF carrier frequency

D31-D0

1111111111110000

Header

LIW

LIW

Command

RM

INPUT

Fig. 6

UM-MODE-1

In UM-MODE-1 the chip sends LB1 and LB0 followed by the 30 Bits of UM1 starting with the MSB following the same

procedure as in ID-MODE. After completion the chip returns to Standby Mode