Hardware description
Figure 20: NFC antenna connector
NFC uses two pins, pin 11 (NFC1) and pin 12 (NFC2), to connect the antenna. These pins are shared with
P0.09
and
P0.10
). The PROTECT field of the NFCPINS register in 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.
Note:
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)
toolchain in use:
• SEGGER Embedded Studio – Select
Project
>
Edit Options
>
Code
>
Preprocessor
>
Preprocessor Definitions
and add the CONFIG_NFCT_PINS_AS_GPIOS variable.
• nRF Connect SDK – Set CONFIG_NFCT_PINS_AS_GPIOS to
y
for instructions.
Pins
P0.09
and
P0.10
are by default configured to use the NFC antenna, but if they are needed as normal
GPIOs,
R25
and
R26
must be not connected (NC) and
R27
and
R28
must be shorted by
0R
.
Figure 21: NFC input
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