BoardPilotRC522 RFID with Nordic nRF52840 DK
Wiring for the RC522 RFID reader (13.56 MHz) on the Nordic nRF52840 DK (nRF52840-QIAA, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.
Wiring
| RC522 RFID pin | Role | Nordic nRF52840 DK pin | Notes |
|---|---|---|---|
| SDA | SPI chip select | P1.12 | This is the SPI chip select (CS), despite the SDA label |
| SCK | SPI clock | P1.15 | |
| MOSI | SPI MOSI | P1.13 | |
| MISO | SPI MISO | P1.14 | |
| IRQ | Interrupt | P1.03 | Interrupt, optional. Leave unconnected |
| GND | Ground | GND | |
| RST | Input to the part | P1.04 | Reset, active LOW |
| 3.3V | Power | VDD | 3.3 V only. Never 5 V |
Check before you power it on
- Supply: 3 V from the VDD pin.
Test code (Arduino)
The Arduino core for this board numbers its pins differently from the chip names, so no code is shown here. Use the pin names from your core’s variant file.
Arduino board: adafruit:nrf52:pca10056. Plug USB into the port on the short edge (interface MCU, J2) and set the power switch to ON; before the first Arduino sketch, burn the Adafruit bootloader and SoftDevice once.
Questions
Which Nordic nRF52840 DK pins do I use for the RC522 RFID?
SDA → P1.12, SCK → P1.15, MOSI → P1.13, MISO → P1.14, IRQ → P1.03, GND → GND, RST → P1.04, 3.3V → VDD.
Does the RC522 RFID work with the Nordic nRF52840 DK at 3.3 V?
Yes: the RC522 RFID runs at 3.3 V and the Nordic nRF52840 DK uses 3.3 V signals, so no level shifting is needed.
BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.
Download BoardPilotFull Nordic nRF52840 DK pinout · RC522 RFID reader (13.56 MHz): all pins and data
The RC522 RFID on other boards
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