nrf5340-hardware - SKILL.md Agent Skill

name: nrf5340-hardware description: "Nordic nRF5340 dual-core SoC hardware reference: application core (Cortex-M33 128MHz), network core (Cortex-M33 64MHz), 2.4GHz radio (BLE 5.3, Thread, Zigbee, ANT, 802.15.4, proprietary), GPIO/SPI/I2C/UART pinout, power domains, DFU bootloader. Use when designing BCI receiver firmware, configuring radio parameters, or debugging hardware peripherals." trit: 0

nRF5340 Hardware

Nordic Semiconductor dual-core wireless SoC. The BCI receiver target for zig-syrup-bci.

Cores

Core	CPU	Clock	Flash	RAM	Role
Application	Cortex-M33 + FPU + DSP	128 MHz	1 MB	512 KB	User logic, DSP, crypto
Network	Cortex-M33	64 MHz	256 KB	64 KB	Radio stack, BLE, Thread

Cores communicate via IPC (inter-processor communication) with shared RAM regions and hardware mutexes.

Radio

Frequency: 2400-2483.5 MHz (ISM band)
Protocols: BLE 5.3, Thread 1.3, Zigbee 3.0, ANT, IEEE 802.15.4, proprietary 2.4GHz
TX Power: -20 to +3 dBm (1 dB steps)
RX Sensitivity: -98 dBm (1 Mbps BLE), -104 dBm (125 kbps coded PHY)
Data Rates: 125 kbps, 500 kbps, 1 Mbps, 2 Mbps
Direction Finding: AoA and AoD (antenna switching)

Key Peripherals

Peripheral	Count	Notes
GPIO	48 pins (P0.0-P0.31, P1.0-P1.15)	3.3V, 6 mA drive
SPI	4 (SPIM)	Up to 32 MHz, EasyDMA
I2C	4 (TWIM)	Up to 400 kHz
UART	4 (UARTE)	Up to 1 Mbps, EasyDMA, HW flow ctrl
ADC	1 (SAADC)	12-bit, 8 channels, 200 ksps
PWM	4	16 MHz base, 4 channels each
PDM	1	Digital microphone interface
I2S	1	Audio codec interface
QSPI	1	External flash, up to 96 MHz
USB	1	Full-speed (12 Mbps), device only
Crypto	1 (CryptoCell-312)	AES, SHA, RSA, ECC, TRNG

Power Domains

Domain	Voltage	Peripherals
VDD	1.7-5.5V	Main supply (internal LDO/DCDC to 1.1V)
VDDH	2.5-5.5V	High-voltage GPIO, USB
DECN	1.0-1.3V	Network core internal
DECA	1.0-1.3V	Application core internal

Power modes: Active (6 mA), Idle (1 mA), System ON sleep (1.5 µA), System OFF (0.4 µA)

Use DCDC converter for battery operation — drops from ~6 mA to ~3 mA active current.

BCI Receiver Pin Assignment (zig-syrup-bci target)

Pin	Function	Connected To
P0.06	UART TX	Debug console
P0.08	UART RX	Debug console
P0.13	SPI SCK	fNIRS ADC (ADS1299)
P0.14	SPI MOSI	fNIRS ADC
P0.15	SPI MISO	fNIRS ADC
P0.16	SPI CS	fNIRS ADC
P0.26	I2C SDA	IMU (LSM6DSO)
P0.27	I2C SCL	IMU
P1.00	GPIO	LED status
P1.01	GPIO	Button (DFU trigger)
P1.09	ADC AIN5	Battery voltage divider

DFU Bootloader

The nRF5340 uses MCUboot as the default bootloader:

# Build with MCUboot
west build -b nrf5340dk/nrf5340/cpuapp -- -DCONFIG_BOOTLOADER_MCUBOOT=y

# Flash via J-Link
west flash

# DFU over BLE (using mcumgr)
mcumgr --conntype ble --connstring peer_name=nRF5340_BCI image upload app_update.bin

# DFU over USB (using nrfutil)
nrfutil dfu serial -pkg dfu_package.zip -p /dev/cu.usbmodem*

Zephyr RTOS

# Setup
west init -m https://github.com/nrfconnect/sdk-nrf
west update

# Build for application core
west build -b nrf5340dk/nrf5340/cpuapp app/

# Build for network core (BLE controller)
west build -b nrf5340dk/nrf5340/cpunet net/

# Flash both cores
west flash --erase

Key Kconfig Options

CONFIG_BT=y                    # Enable Bluetooth
CONFIG_BT_PERIPHERAL=y         # Peripheral role
CONFIG_BT_DIS=y                # Device Information Service
CONFIG_BT_NUS=y                # Nordic UART Service
CONFIG_BT_CTLR=y               # BLE controller on network core
CONFIG_IPC_SERVICE=y            # Inter-core communication
CONFIG_HEAP_MEM_POOL_SIZE=8192
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

Relevant Datasheets

nRF5340 Product Specification v1.3: infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf5340
nRF5340-DK User Guide: infocenter.nordicsemi.com/topic/ug_nrf5340_dk

Related Skills

Skill	Connection
zig-syrup-bci	BCI receiver firmware target
cyton-dongle	2.4GHz radio comparison (RFDuino vs nRF5340)
opennirscap-build	fNIRS sensor connected via SPI
nrf5340-device-interaction	Software/firmware interaction patterns