EM4170
Word Organisation
First bit input
Data Row Even Parity
D15 D14 D13 D12 P3
D11 D10 D09 D08 P2
D07 D06 D05 D04 P1
D03 D02 D01 D00 P0
PC3 PC2 PC1 PC0
0
Column Even Parity
Last bit input
logic "0"
Fig. 10
After reception of the write command, the address and the data, the EM4170 will check the parity and the Lock-Bits. If all
the conditions are fulfilled, an Acknowledge pattern (ACK) will be issued, 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 Standby Mode.
The EM4170 might also return to the Standby Mode without sending back a NAK if the incoming data is corrupted and/or
inconsistent.
As there is no check of the power supply before writing, the system has to assure that there is enough power received by
the tag (VDD≥2.6V), when performing the write command.
Write word
twee
Twa
OUTPUT
INPUT
LIW
RM
ACK
ACK
LIW
WRITE WORD ADDRESS
DATA
Fig. 11
Write Word
Begin
Receive
Command
valid ?
Y
N
Receive
Address
Send
ACK
Receive
Data
Write
Data
Send
ACK
Send
NAK
End
Fig. 12
8
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