mfrc522 NXP Semiconductors, mfrc522 Datasheet - Page 63

• Manufacturer Part Number: mfrc522
• Description: Contactless Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
112132
Product data sheet
11.3 Serial Data Switch
11.4 MFIN/MFOUT interface support
Two main blocks are implemented in the MFRC522. A digital circuitry, comprising state
machines, coder and decoder logic and an analog circuitry with the modulator and
antenna drivers, receiver and amplification circuitry. For example, the interface between
these two blocks can be configured in the way, that the interfacing signals may be routed
to the pins MFIN and MFOUT.
This topology supports, that the analog part of the MFRC522 may be connected to the
digital part of another device.
The serial signal switch is controlled by the register TxSelReg and RxSelReg.
The following figure shows the serial data switch for TX1 and TX2.
The MFRC522 is basically divided into digital circuitry and analog circuitry. The digital
circuitry contains state machines, coder and decoder logic and so on and the analog
circuitry contains the modulator and antenna drivers, receiver and amplification circuitry.
The interface between these two blocks can be configured in the way, that the interfacing
signals may be routed to the pins MFIN and MFOUT (see
MFIN/MFOUT Signal
and UARTSel of registers TxSelReg and RxSelReg.
This topology supports, that some parts of the analog part of the MFRC522 may be
connected to the digital part of another device.
The switch MFOutSel in register TxSelReg can be used to measure MIFARE
ISO/IEC14443 related signals. This is especially important during the design In phase or
for test purposes to check the transmitted and received data.
However, the most important use of MFIN/MFOUT pins is the active antenna concept. An
external active antenna circuit can be connected to the digital circuit of the MFRC522.
MFOutSel has to be configured in that way that the signal of the internal Miller Coder is
send to MFOUT pin (MFOutSel = 4). UARTSel has to be configured to receive
Manchester signal with sub-carrier from MFIN pin (UARTSel = 1).
It is possible, to connect a 'passive antenna' to pins TX1, TX2 and RX (via the appropriate
filter and matching circuit) and at the same time an Active Antenna to the pins MFOUT
and MFIN. In this configuration, two RF-parts may be driven (one after another) by one
host processor.
Fig 20. Serial data switch for TX1 and TX2.
MFIN
internal
Coder
InvMod=1
PolMfin =0
invert if
invert if
Routing”). The configuration is done by bits MFOutSel, DriverSel
Rev. 3.2 — 22 May 2007
Envelope
Tristate
Figure 21 “Overview
1
DriverSel
00
01
10
11
Contactless Reader IC
MFRC522
To driver TX1 and TX2
0 = impedance = MOD
1 = inpedance = CW
© NXP B.V. 2007. All rights reserved.
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