mfrc531 NXP Semiconductors, mfrc531 Datasheet - Page 63

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

NXP Semiconductors
MFRC531_34
Product data sheet
PUBLIC
10.5.4.5 RxThreshold register
10.5.4.6 BPSKDemControl
Selects thresholds for the bit decoder.
Table 88.
Table 89.
Controls BPSK demodulation.
Table 90.
Table 91.
Bit
Symbol
Access
Bit
7 to 4
3 to 0
Bit
Symbol
Access
Bit
7
6
5
4
3 to 2
1 to 0
Symbol
NoRxSOF
NoRxEGT
NoRxEOF
FilterAmpDet -
TauD[1:0]
TauB[1:0]
Symbol
MinLevel[3:0]
CollLevel[3:0]
RxThreshold register (address: 1Ch) reset value: 1111 1111b, FFh bit allocation
RxThreshold register bit descriptions
BPSKDemControl register (address: 1Dh) reset value: 0001 1110b, 1Eh bit
allocation
BPSKDemControl register bit descriptions
NoRxSOF NoRxEGT NoRxEOF FilterAmpDet
R/W
7
7
Rev. 3.4 — 26 January 2010
Value
1
0
1
0
1
0
-
-
R/W
MinLevel[3:0]
6
6
Description
the minimum signal strength the decoder will accept. If the signal
strength is below this level, it is not evaluated.
the minimum signal strength the decoder input that must be reached
by the weaker half-bit of the Manchester encoded signal to generate
a bit-collision (relative to the amplitude of the stronger half-bit)
Description
a missing SOF in the received data stream is ignored and no
framing errors are indicated
a missing SOF in the received data stream generates framing
errors
an EGT which is too short or too long in the received data stream
is ignored and no framing errors are indicated
an EGT which is too short or too long in the received data stream
will cause framing errors
a missing EOF in the received data stream is ignored and no
framing errors indicated
a missing EOF in the receiving data stream produces framing
errors
switches on a high-pass filter for amplitude detection
changes the time constant of the internal PLL whilst receiving
data
changes the time constant of the internal PLL during data bursts
R/W
056634
R/W
5
5
4
R/W
4
3
3
TauD[1:0]
R/W
ISO/IEC 14443 reader IC
CollLevel[3:0]
2
R/W
2
MFRC531
© NXP B.V. 2010. All rights reserved.
1
1
TauB[1:0]
R/W
63 of 116
0
0