nRF5340 wiring#

Every pin and connection on the nRF bench stack. Bring-up is nrf5340-bringup.md.

Source of truth#

../apps/nrf5340dk-lock/overlays/dw3000-nfc.overlay is authoritative: the build compiles it and it cannot drift. What a devicetree cannot carry is here: Arduino header positions, far-end pin names, power rails and stack order. If the two disagree, the overlay wins.

Resolved from the generated build/matter-aliro-door-lock-app/zephyr/zephyr.dts:

Header positions from the arduino_header node's gpio-map, where map indices 0 to 5 are A0 to A5 and 6 onward are D0 to D15.
Peripheral claims by decoding each psels value, which encodes (function << 24) | (port * 32 + pin).
Chip selects and side-band lines from cs-gpios, irq-gpios, reset-gpios and wakeup-gpios on the device nodes.

Stack order#

X-NUCLEO-NFC12A1 (ST25R300)     NFC front end, SPIM1 @ 4 MHz
        |
Arduino Proto R3                upper patch panel
        |   9 jumpers
Arduino Proto R3                lower patch panel
        |
DWM3000EVB (DW3110)             UWB radio, SPIM4 @ 8 MHz, seated on the DK
        |
nRF5340 DK

The two proto shields are a patch panel: nothing crosses between them except the jumpers you fit, power included. The DWM3000EVB occupies the native Arduino SPI positions D10 to D13, so the NFC board cannot also use them and its signals are re-routed to A2 to A5 on the way up.

The EVB also spaces everything above it clear of the DK's P5 and P20 connectors. The vendor documents contact with those connectors as a cause of NFC driver initialization failures.

Every pin and every connection#

Each row reads left to right as the signal's path up the stack. The DWM Arduino pin is the DK's own header position, carried through the seated EVB onto the lower proto shield. The step from there to the X-NUCLEO Arduino pin is a jumper between the two proto shields. A dash means the signal stops there.

nRF pin	DWM3000EVB	DWM Arduino pin	X-NUCLEO Arduino pin	X-NUCLEO NFC12A1
P0.04	pass through	A0	-	-
P0.05	pass through	A1	-	-
P0.06	pass through	A2	D13	SCK
P0.07	pass through	A3	D11	MOSI
P0.25	pass through	A4	D12	MISO
P0.26	pass through	A5	D10	CS, active low
P1.00	pass through	D0	-	-
P1.01	pass through	D1	-	-
P1.04	pass through	D2	-	-
P1.05	pass through	D3	-	-
P1.06	pass through	D4	-	-
P1.07	pass through	D5	D8	RESET, active low, pull-down
P1.08	pass through	D6	A0	IRQ, active high
P1.09	RESET, active low	D7	-	-
P1.10	IRQ, active high	D8	-	-
P1.11	WAKEUP, active high	D9	-	-
P1.12	CS, active low	D10	-	-
P1.13	MOSI	D11	-	-
P1.14	MISO	D12	-	-
P1.15	SCK	D13	-	-
P1.02	pass through	D14	-	-
P1.03	pass through	D15	-	-
rail	pass through	3V3	3V3	VDDIO
rail	pass through	5V	5V	VBUS
rail	pass through	GND	GND	ground

Nine rows carry a bold pair: those are the nine jumpers, and nothing else on the stack is wired by hand. Rows where the DWM3000EVB column names a function are the DW3000's own seven signals, taken at the EVB and never carried further up.

Pins reserved by the SoC though nothing on this stack uses them: P1.00 and P1.01 are UART1 RX and TX, P1.02 and P1.03 are I2C1 SDA and SCL. Do not borrow D0, D1, D14 or D15. Free: A0, A1, D2, D3, D4.

Two mistakes to avoid:

The four SPI jumpers cross headers. The DWM side is analog (A2 to A5), the X-NUCLEO side is digital (D13, D11, D12, D10). A jumper that looks symmetrical is wrong.
The three power jumpers are not optional. The proto shields pass no power through on their own.

The RESET jumper, DWM D5 to X-NUCLEO D8, is the one value not taken from the overlay or a vendor wiring table. The vendor tables omit reset, and reset-gpios is optional in the x-nucleo-nfc binding. D8 on the NFC side is derived from the add-on's own seated overlay, where reset sits on P1.10, which is D8. Confirm against the board pinout before trusting it.

Off-header pins, not spares: UART0 console on P0.19 to P0.22, LED1 PWM on P0.28, external QSPI flash on P0.13 to P0.18.

Before powering#

3.3 V only, never 5 V on the DW3000, and share a common ground with the DK.
Set the DWM3000EVB power-select jumper before anything else. The wrong position makes SPI fail silently, with no device ID and a responder that never listens. Use the 3.3 V source and read the silkscreen next to the jumper block.

Failure signatures#

Console line	Meaning
`RFAL: NFC initialization failed`	No SPI conversation with the ST25R300. Check the four SPI jumpers (A2 to A5), the RESET jumper (D5), and the three power jumpers. A loose IRQ jumper (D6) usually still lets init pass.
`NFC transport start failed` then `Failed to start Aliro: 1`	Follows the above. `AliroStart()` starts the NFC transport first and returns on failure, so BLE advertising never starts either and the reader is silent on air even though Matter still works.
`dwt_probe failed: -1, raw DEV_ID=0xffffffff`	No SPI conversation with the DW3110. Expected when the EVB is absent. Otherwise check the power-select jumper first, then the EVB's seated contacts on D7 to D13.

Broader SPI and ranging failure modes: troubleshooting.md.