CLRC63201T View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'CLRC63201T' PDF : 127 Pages View PDF
NXP Semiconductors
CLRC632
Standard multi-protocol reader solution
9.10.2.3 Correlation circuitry
The correlation circuitry calculates the degree of matching between the received and an
expected signal. The output is a measure of the amplitude of the expected signal in the
received signal. This is done for both, the Q and I-channels. The correlator provides two
outputs for each of the two input channels, resulting in a total of four output signals.
The correlation circuitry needs the phase information for the incoming card signal for
optimum performance. This information is defined for the microprocessor using the
BitPhase register. This value defines the phase relationship between the transmitter and
receiver clock in multiples of the BitPhase time (tBitPhase) = 1 / 13.56 MHz.
9.10.2.4 Evaluation and digitizer circuitry
The correlation results are evaluated for each bit-half of the Manchester coded signal. The
evaluation and digitizer circuit decides from the signal strengths of both bit-halves, if the
current bit is valid
• If the bit is valid, its value is identified
• If the bit is not valid, it is checked to identify if it contains a bit-collision
Select the following levels for optimal using RxThreshold register bits:
• MinLevel[3:0]: defines the minimum signal strength of the stronger bit-halve’s signal
which is considered valid.
• CollLevel[3:0]: defines the minimum signal strength relative to the amplitude of the
stronger half-bit that has to be exceeded by the weaker half-bit of the Manchester
coded signal to generate a bit-collision. If the signal’s strength is below this value,
logic 1 and logic 0 can be determined unequivocally.
After data transmission, the card is not allowed to send its response before a preset time
period which is called the frame guard time in the ISO/IEC 14443 standard. The length of
this time period is set using the RxWait register’s RxWait[7:0] bits. The RxWait register
defines when the receiver is switched on after data transmission to the card in multiples of
one bit duration.
If bit RcvClkSelI is set to logic 1, the I-clock is used to clock the correlator and evaluation
circuits. If bit RcvClkSelI is set to logic 0, the Q-clock is used.
Remark: It is recommended to use the Q-clock.
9.11 Serial signal switch
The CLRC632 comprises two main blocks:
• digital circuitry: comprising the state machines, encoder and decoder logic etc.
• analog circuitry: comprising the modulator, antenna drivers, receiver and
amplification circuitry
The interface between these two blocks can be configured so that the interface signals
are routed to pins MFIN and MFOUT. This makes it possible to connect the analog part of
one CLRC632 to the digital part of another device.
The serial signal switch can be used to measure MIFARE and ISO/IEC 14443 A as well as
related I-CODE1 and ISO/IEC 15693 signals.
CLRC632
Product data sheet
COMPANY PUBLIC
All information provided in this document is subject to legal disclaimers.
Rev. 3.7 — 27 February 2014
073937
© NXP Semiconductors N.V. 2014. All rights reserved.
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