EM4450

EM4550

Copyright

 2003, EM Microelectronic-Marin SA

4

www.emmicroelectronic.com

Timing Characteristics

unless otherwise specified

All timings are derived from the field frequency and are specified as a number of RF periods..

Parameter

Symbol

Conditions

Value

Unit

Option : 64 clocks per bit

Opt64

Read Bit Period

64

RF periods

LIW/ACK/NACK pattern duration

320

RF periods

Read 1 Word Duration

including LIW

3200

RF periods

Processing Pause Time

64

RF periods

Write Access Time

64

RF periods

Initialization Time

2112

RF periods

EEPROM write time

3200

RF periods

Option : 32 clocks per bit

Opt32

Read Bit Period

32

RF periods

LIW/ACK/NACK pattern duration

160

RF periods

Read 1 Word Duration

including LIW

1600

RF periods

Processing Pause Time

32

RF periods

Write Access Time

32

RF periods

Initialization Time

1056

RF periods

EEPROM write time

2624

RF periods

RF periods represent periods of the carrier frequency emitted by the transceiver unit. For example, if 125 kHz is used :

The Read bit period (Opt64) would be : 1/125'000*64 = 512 µs, and the time to read 1 word : 1/125'000*3200 = 25.6 ms.

The Read bit period (Opt32) would be : 1/125'000*32 = 256 µs, and the time to read 1 word : 1/125'000*1600 = 12.8 ms.

ATTENTION

Due to amplitude modulation of the coil-signal, the clock-extractor may miss clocks or add spurious clocks close

to the edges of the RF-envelope. This desynchronisation will not be larger than ±3 clocks per bit and must be

taken into account when developing reader software.

Functional Description

General

The EM4450/4550 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

EM4450/4550 will turn to the Receive Mode (RM) if it receives a valid RM pattern. The chip then expects a valid command.

Mode of Operation

Fig. 4

Get Command

Standard

Read Mode

Send w ord

Pow er-On

Write Word

Write Password

Selective Read

Login

YES

NO

Receive

Mode

request ?

Reset

Execute Command

Init