Data Sheet

LC840PA
Datasheet
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5.5 NFC
NFC support:
▪ Based on the NFC forum specification
– 13.56 MHz
– Date rate 106 kbps
– NFC Type 2 and Type 4 tag emulation
▪ Modes of operation:
– Disable
– Sense
– Activated
5.5.1 Use Cases
▪ Touch to pair with NFC
▪ Launch a smartphone app (on Android)
▪ NFC enabled Out-of-Band Pairing
▪ System Wake-On-Field function
– Proximity Detection
–
The ProFLEX firmware does not use NFC.
Table 16: NFC interface
Signal Name
Pin No
I/O
Comments
NFC1/SIO_09
59
I/O
The NFC pins are by default NFC pins and an alternate function on each pin
is GPIO. Refer to the smartBASIC. User manual.
NFC2/SIO_10
57
I/O
5.5.2 NFC Antenna Coil Tuning Capacitors
From Nordic’s nRF52840 Objective Product Specification v1.0: http://infocenter.nordicsemi.com/pdf/nRF52840_PS_v1.0.pdf
The NFC antenna coil must be the connected differential between the NFC1 and NFC2 pins of the LC840PA. Two external
capacitors should be used to tune the resonance of the antenna circuit to 13.56 MHz (Figure 5).
Figure 5: NFC antenna coil tuning capacitors
The required external tuning capacitor value is given by the following equation: