MN63Y1208 Datasheet, PDF (88/120 Pages) Panasonic Semiconductor – Built-in 4-Kbit FeRAM non-volatile memory with fast write and low power consumption

Chapter 7 Tunnel Mode
7.3 Communication between Host and RFID
This section describes the I2C communication between the host and RFID in tunnel mode.
7.3.1.1 Communication Specification
The specification for I2C communication is the same as that for serial communication mode. See Section 5.2
I2C.
QUERY and ANSWER commands are provided only for tunnel mode. For more information about commands,
see Section 7.4 Command.
7.3.1.2 IRQ Notification
Once this RFID receives a tunnel mode command from reader/writer, it sends an IRQ to the host.
IRQ is output from the NIRQ pin. The NIRQ pin also outputs IRQs in other modes than tunnel mode by setting
the system area HW2 parameter's IRQSEL. For more information about IRQSEL, see Section 3.3 HW1
(2 bytes) in Section System Area.
When the host receives an IRQ and detects that the supply voltage VDDEX is not applied, it applies VDDEX
and sends a QUERY command to the RFID. The RFID can receive I2C commands at the falling edge of
NIRQ.
In addition, if the RFID does not receive a QUERY command from the host even when the maximum wait time
for QUERY command specified in the system area QWT elapses after the NIRQ pin outputs low, it detects a
timeout. For more information, see Section 9.3 Flow Chart in Tunnel Mode.
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