EM4169B6CI2LB 데이터 시트보기 (PDF) - EM Microelectronic - MARIN SA

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EM4169B6CI2LB

128 bit Read/Write Contactless Identification Device with OTP function

EM Microelectronic - MARIN SA 

The Write Configuration word command procedure is the

same as above, the only exception is that only CRC

verification and power check are done.

Writing to EEPROM lasts 20 ms.

After successful writing of EEPROM the IC sends an

acknowledge pattern to confirm the completion of writing.

Acknowledge pattern consists of switching the modulator

load ON and OFF with a signal period of 256 µs (Option 64

clocks/bit) or 128 µs (Option 32 clocks/bit) representing

half a bit period (a quarter of bit period ON, a quarter of bit

period OFF). Acknowledge pattern is transmitted during a

time equivalent to two bit periods. Pulses of this length do

not occur during data readout so the acknowledge pattern

is easily recognizable.

tRDB

tRDB

Acknowledge pattern

Fig. 13

After sending the acknowledge pattern the EM4069

transitions to the Start Bit Detection state and waits for the

start bit of next command. In this way, several words can

be written to EEPROM without returning in read mode after

every write. The value of the timer is 2 tRDB.

Disabling of Command Detection

In certain cases the IC logic blocks the detection of the

Synchronization pattern Envelope during one complete

readout cycle of 128 bits. This is valid in the following

cases :

at power up (after POR)

after a Reset command

after a time out occurs in the Start Bit Detection state

(only in the case the transition to Start Bit Detection

state was done from Read mode)

Details about command timing

Command timing is based on NRZ (non-return to zero)

modulation on the magnetic field (as shown in figure 11).

EM4069

EM4169

NRZ modulation is simple and leads to good results in

proximity of the reader. To send a bit-1, the reader does

not modulate the signal for a complete bit period, and to

send a bit-0, it modulates the carrier frequency during a

whole bit period.

Long streams of zeros (in write command data sequence

or CRC) reduce writing distance due to drop of supply

voltage under POR level, due to the long time the carrier

frequency is in LOW field mode.

The writing distance can be improved by using RTO (return

to one) modulation coding. Short burst of high field

(approximately 1/4 of bit period) during transmission of a

bit-0 to EM4069, recharge the on-board power supply

buffer capacitor. To operate in this way, it is important to be

synchronized with the sampling rate of the EM4069.

Figure 14 shows the processing of hexadecimal data “96”

in the write command string. The following signals are

drawn :

EM4069 : shows the modulator state. The “low” peak to

peak value indicates that the modulator load is connected,

and a “high” peak to peak value means that the modulator

load is disconnected.

NRZ : Reader generated field. Low field is forced when

sending a bit-0 and High field for a bit-1. The field is at the

same level for the whole bit duration.

RTO : Reader generated field as NRZ, with a burst of high

field during 1/4 period for the transmission of a bit-0.

At the beginning of timing diagram, the EM4069 is in start

bit detection state, modulator load and peak detector are

ON. When the start bit is detected, the logic transitions in

command processing state. 3/8 to 1/2 of a bit period after

beginning of start bit (T1), EM4069 starts putting the

modulator load half bit period OFF and half bit period ON.

The sample of field strength which gives to the logic the

value of bit is taken at the end of ON period.

Assuming that the start bit duration is 1 bit period, the

following bit samples are taken 3/8 to 1/2 of bit period after

start of each bit period. So during the last quarter of bit

period the field can be put high to recharge the EM4069

on-board capacitor.

The sampling point can be moved by changing the start bit

duration.

Copyright  2003, EM Microelectronic-Marin SA

11

www.emmicroelectronic.com

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