The nRF52 DK supports a Near Field Communication (NFC) tag.
NFC-A Listen Mode operation is supported on the nRF52832 System on Chip (SoC). The NFC antenna input is available on connector P23 on the nRF52 DK.
Figure 1. NFC antenna connector
NFC uses two pins, NFC1 and NFC2, to connect the antenna. These pins are shared with General-Purpose Input/Output (GPIO)s (P0.09 and P0.10). The PROTECT field of the NFCPINS register in User Information Configuration Registers (UICR) defines the usage of these pins and their protection level against abnormal voltages. The content of the NFCPINS register is reloaded at every reset.
Configuring NFC pins as GPIOs
The NFC pins are enabled by default. NFC can be disabled and GPIOs enabled by defining the CONFIG_NFCT_PINS_AS_GPIOS variable in the project settings. This is configured based on the Integrated Development Environment (IDE) or toolchain in use:- SEGGER Embedded Studio – Select and add the CONFIG_NFCT_PINS_AS_GPIOS variable.
- nRF Connect SDK – Set CONFIG_NFCT_PINS_AS_GPIOS to y. See Configuring your application for instructions.
Pins P0.09 and
P0.10 are by default configured to use the
NFC antenna. To use these pins as GPIO, R25 and R26 must be not
connected (NC) and R27 and R28 must be shorted with an OR resistor.
Figure 2. NFC input
