R

EM4150

EM4350

Write Word (cont.)

After reception of the command, the address, and the data, the EM4150 will check the parity, the write protection status, the

Login status, and also if the available power from the RF field is sufficient. If all the conditions are satisfied, an acknowledge

pattern (ACK) will be issued afterward and the EEPROM writing process will start. At the end of programming, the chip will

send an Acknowledge pattern (ACK). If at least one of the checks fails, the chip will issue a no acknowledge pattern (NAK)

instead of ACK and return to the Standard Read Mode. The Transceiver will keep the RF field permanently "ON" during the

whole writing process time.

The Read After Write function (bit 17 of Control word) controls the mode of operation following a write operation. When

"ON" the latest written word will be read out and output next to the ACK pattern and two Listen Windows (LIW-LIW) even if

the word is read protected. When "OFF", the ACK is followed immediately by a LIW-LIW and FWR. The last written word is

not output.

If a request from the transceiver to return in receive mode (RM) is generated during the LIW, another word can be written in.

Otherwise, the EM4150 will return in the Standard Read Mode.

OUTPUT

WORD n

LIW

INPUT

ACK

RM WRITE WORD ADDRESS

DATA

ACK

LIW

OUTPUT

WORD n

LIW

INPUT

NAK

RM WRITE WORD ADDRESS

DATA

LIW

Write 1 word

Write several words

Read After Write function

OUTPUT

WORD n

LIW

INPUT

ACK

RM WRITE WORD ADDRESS

DATA

ACK

LIW

RM WRITE WORD ADDRESS

DATA

OUTPUT

WORD n

LIW

INPUT

ACK

RM WRITE WORD ADDRESS

DATA

ACK

Last Written

LIW

FWR

LIW

FWR

LIW

LIW

FWR

LIW

Note: The Last Written is outpout

even if Read Protected.

TRANSCEIVER RF FIELD "ON"

TRANSCEIVER RF FIELD "ON"

TRANSCEIVER RF FIELD "ON"

TRANSCEIVER RF FIELD "ON"

LIW

Fig. 17

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