P4069 EM Microelectronic, P4069 Datasheet - Page 11

• Manufacturer Part Number: P4069
• Description: 128 Bit Read/write Contactless Identification Device With Otp Function
• Manufacturer: EM Microelectronic

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.
After sending the acknowledge pattern the P4069
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 t
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 :
Details about command timing
Command timing is based on NRZ (non-return to
zero) modulation on the magnetic field (as shown in
figure 11). NRZ modulation is simple and leads to
RDB
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)
.
t
Acknowledge pattern
RDB
The
EM MICROELECTRONIC-MARIN SA
Write
Configuration
t
RDB
Figure 13
word
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)
transmission of a bit-0 to P4069, 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 P4069.
“96” in the write command string. The following
signals are drawn :
P4069 : 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 P4069 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),
P4069 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 P4069 on-board capacitor.
The sampling point can be moved by changing the
start bit duration.
Figure 14 shows the processing of hexadecimal data
P4069/P4169
during
11