EM4205-EM4305
EEPROM Delivery State
Forward Link Communication
(Communication from the Reader to the Tag)
Default configuration is the following:
First two words (word 0 and 1) are programmed with:
As already mentioned, the commands are sent from the
reader to the tag by initiating a command while the
EM4205/4305 is in default read mode. The
communication is done by using 100% modulation index
of reader field (also called field stops or OOK) with a bit
timing of 32 periods of the RF field. The forward link
Chip Type
Resonant capacitor version
Customer Code
Unique Identification Number (UID).
communication
protocol
is
identical
to
the
All the other user free memory words are set to 0.
EM4569/EM4469.
The chip is initialized to Bi-phase data encoding, RF/32
clock data rate. Its LWR value is set to 8.
When the EM4205/4305 is in Default read mode, the logic
permanently observes the Data Extractor output (see also
Timing Characteristics and Block Diagram). The detection
of field stop initializes the Command mode.
Default Read
After the supply voltage crosses the POR threshold, the
circuit enters Power-up Initialization in which it reads the
configuration word and then transitions to Default Read
mode according to configuration just read.
At reception of the first field stop, the IC stops immediately
the default read and expects to receive a bit "0" to enter in
the command processing mode. The transceiver and the
chip are now synchronized and further data is sent. In the
case where the first field stop is not followed by bit “0”, the
IC returns in Default read mode.
In Default Read mode, the EM4205/4305 sends
continuously its memory data starting from Word 5 and
finishing with the last word according to the configuration
word settings. After sending the last bit of the last word,
readout continues without interruption with the first bit of
Word 5.
The bit timing is composed of two states called MOD_ON
and MOD_OFF (see figure 10). During the first 16
periods, the modulator is turned OFF (MOD_OFF)
allowing the recharge of the internal supply capacitor.
Then, the chip modulator is turned ON for the next 16
periods (MOD_ON). To receive a logic "0" bit, the IC has
to detect a field stop before the end of MOD_ON state. If
this field stop is not detected, a logic "1" is received.
8
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Copyright 2013, EM Microelectronic-Marin SA
4205-4305-DS-01.doc, Version 4.0, 22-Oct-13
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