CLRC663 Datasheet, PDF (29/132 Pages) NXP Semiconductors – Contactless reader IC

NXP Semiconductors
CLRC663
Contactless reader IC
Table 24. Timing parameter I²CL
Parameter
Min
t_SU;SDA
t_HD;DAT
t_SU;DAT
t_SU;STO
t_BUF
80
0
0
80
200
Max
-
50
20
-
-
Unit
ns
ns
ns
ns
ns
The pull-up resistor is not required for the I²CL interface. Instead, a on chip buskeeper is
implemented in the CLRC663 for SDA of the I²CL interface. This protocol is intended to be
used for a point to point connection of devices over a short distance and does not support
a bus capability.The driver of the pin must force the line to the desired logic voltage. To
avoid that two drivers are pushing the line at the same time following regulations must be
fulfilled:
SCL: As there is no clock stretching, the SCL is always under control of the Master.
SDA: The SDA line is shared between master and slave. Therefore the master and the
slave must have the control over the own driver enable line of the SDA pin. The following
rules must be followed:
• In the idle phase the SDA line is driven high by the master
• In the time between start and stop condition the SDA line is driven by master or slave
when SCL is low. If SCL is high the SDA line is not driven by any device
• To keep the value on the SDA line a on chip buskeeper structure is implemented for
the line
8.4.5 SAM interface I²C
8.4.5.1 SAM functionality
The CLRC663 implements a dedicated I2C interface to integrate a MIFARE SAM (Secure
Access Module) in a very convenient way into applications (e.g. a proximity reader).
The SAM can be connected to the microcontroller to operate like a cryptographic
co-processor. For any cryptographic task, the microcontroller requests a operation from
the SAM, receives the answer and sends it over a host interface (e.g. I2C, SPI) interface
to the connected reader IC.
The MIFARE SAM supports a optimized method to integrate the SAM in a very efficient
way to reduce the protocol overhead. In this system configuration, the SAM is integrated
between the microprocessor and the reader IC, connected by one interface to the reader
IC and by another interface to the microcontroller. In this application the microcontroller
accesses the SAM using the T=1 protocol and the SAM accesses the reader IC using an
I2C interface. As the SAM is directly communicating with reader IC, the communication
overhead is reduced. In this configuration, a performance boost of up to 40% can be
achieved for a transaction time.
The MIFARE SAM supports applications using MIFARE cards. For multi application
purposes an architecture connecting the microcontroller additionally directly to the reader
IC is recommended. This is possible by connecting the CLRC663 on one interface (SAM
Interface SDA, SCL) with the MIFARE SAM AV2.6 (P5DF081XX/T1AR1070) and by
connecting the microcontroller to the S2C or SPI interface.
CLRC663
Product data sheet
COMPANY PUBLIC
All information provided in this document is subject to legal disclaimers.
Rev. 3.3 — 3 April 2012
171133
© NXP B.V. 2012. All rights reserved.
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