mfrc531 NXP Semiconductors, mfrc531 Datasheet - Page 64

• Manufacturer Part Number: mfrc531
• Description: Iso/iec 14443 Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
MFRC531_34
Product data sheet
PUBLIC
10.5.4.7 RxControl2 register
10.5.4.8 ClockQControl register
Controls decoder behavior and defines the input source for the receiver.
Table 92.
Table 93.
[1]
Controls clock generation for the 90° phase-shifted Q-clock.
Table 94.
Table 95.
Bit
Symbol
Access
Bit
7
6
5 to 2
1 to 0
Bit
Symbol
Access
Bit
7
6
5
4 to 0
I-clock and Q-clock are 90° phase-shifted from each other.
Symbol
RcvClkSelI
RxAutoPD
0000
DecoderSource[1:0]
Symbol
ClkQ180Deg
ClkQCalib
0
ClkQDelay[4:0]
RxControl2 register (address: 1Eh) reset value: 0100 0001b, 41h bit allocation
RxControl2 register bit descriptions
ClockQControl register (address: 1Fh) reset value: 000x xxxxb, xxh bit allocation
ClockQControl register bit descriptions
RcvClkSelI
ClkQ180Deg ClkQCalib
R/W
7
R
7
Rev. 3.4 — 26 January 2010
RxAutoPD
R/W
Value
1
0
0
1
-
-
6
R/W
Value Description
1
0
1
0
-
00
01
10
11
056634
6
Description
Q-clock is phase-shifted more than 180° compared to the
I-clock
Q-clock is phase-shifted less than 180° compared to the
I-clock
Q-clock is automatically calibrated after the reset phase and
after data reception from the card
no calibration is performed automatically
this value must not be changed
this register shows the number of delay elements used to
generate a 90° phase-shift of the I-clock to obtain the
Q-clock. It can be written directly by the microprocessor or
by the automatic calibration cycle.
I-clock is used as the receiver clock
Q-clock is used as the receiver clock
receiver circuit is automatically switched on before
receiving and switched off afterwards. This can be used to
reduce current consumption.
receiver is always activated
these values must not be changed
selects the source for the decoder input
5
LOW
internal demodulator
a subcarrier modulated Manchester encoded signal on
pin MFIN
a baseband Manchester encoded signal on pin MFIN
R/W
5
0
4
4
0000
R/W
3
3
ClkQDelay[4:0]
ISO/IEC 14443 reader IC
2
2
D
[1]
MFRC531
[1]
DecoderSource[1:0]
© NXP B.V. 2010. All rights reserved.
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