mfrc522 NXP Semiconductors, mfrc522 Datasheet - Page 30

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

NXP Semiconductors
112132
Product data sheet
9.2.2.10 DemodReg
9.2.2.9 RxThresholdReg
Selects thresholds for the bit decoder.
Table 55:
Table 56:
Defines demodulator settings.
Table 57:
Table 58:
Bit
7 to 4
3
2 to 0
Bit
7 to 6
5
4
3 to 2
1 to 0
Symbol
Access
Symbol
Access
Rights
Rights
Bit
Bit
Symbol
AddIQ
FixIQ
-
TauRcv
TauSync
Symbol
MinLevel
-
CollLevel
Description of RxThresholdReg bits
DemodReg register (address 19h); reset value: 4Dh
Description of DemodReg bits
RxThresholdReg register (address 18h); reset value: 84h
7
7
AddIQ
r/w
Description
Defines the use of I and Q channel during reception
Remark: FixIQ has to be set to logic 0 to enable the following settings.
Value
00
01
10
11
If set to logic 1 and the bits AddIQ are set to X0b, the reception is fixed to
I channel.
If set to logic 1 and the bits AddIQ are set to X1b, the reception is fixed to
Q channel.
Reserved for future use.
Changes the time constant of the internal PLL during data reception.
Remark: If set to 00b, the PLL is frozen during data reception.
Changes the time constant of the internal PLL during burst.
Description
Defines the minimum signal strength at the decoder input that shall be
accepted. If the signal strength is below this level, it is not evaluated.
Reserved for future use.
Defines the minimum signal strength at the decoder input that has to be
reached by the weaker half-bit of the Manchester-coded signal to
generate a bit-collision relatively to the amplitude of the stronger half-bit.
Rev. 3.2 — 22 May 2007
6
6
MinLevel
r/w
Description
Select the stronger channel
Select the stronger channel and freeze the selected during
communication
Reserved
Reserved
FixIQ
r/w
5
5
RFU
4
4
-
RFU
3
3
-
TauRcv
r/w
2
2
Contactless Reader IC
MFRC522
CollLevel
© NXP B.V. 2007. All rights reserved.
r/w
1
1
TauSync
r/w
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0
0