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.
twa
twee
Write 1 word
OUTPUT
INPUT
WORD n
LIW
ACK
ACK
LIW
LIW
FWR
RM WRITE WORD ADDRESS
DATA
DATA
DATA
TRANSCEIVER RF FIELD "ON"
twa
twee
Write several words
OUTPUT
WORD n
LIW
LIW
ACK
ACK
INPUT
RM WRITE WORD ADDRESS
RM WRITE WORD ADDRESS DATA
TRANSCEIVER RF FIELD "ON"
twa
twee
Note: The Last Written is outpout
even if Read Protected.
Read After Write function
OUTPUT
INPUT
WORD n
LIW
ACK
ACK LIW LIW Last Written LIW
LIW
FWR
RM WRITE WORD ADDRESS
TRANSCEIVER RF FIELD "ON"
twa
OUTPUT
INPUT
WORD n
LIW
NAK
LIW
LIW
FWR
RM WRITE WORD ADDRESS
DATA
TRANSCEIVER RF FIELD "ON"
Fig. 17
8
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