Arduino Nano 33 BLE (Sense)

Overview

The Arduino Nano 33 BLE is designed around Nordic Semiconductor’s nRF52840 ARM Cortex-M4F CPU. Arduino sells 2 variants of the board, the plain BLE [1] type and the BLE Sense [2] type. The “Sense” variant is distinguished by the inclusion of more sensors, but otherwise both variants are the same.

The Sense variant of the board

Hardware

Supported Features

The package is configured to support the following hardware:

Interface	Controller	Driver/Component
ADC	on-chip	adc
CLOCK	on-chip	clock_control
FLASH	on-chip	flash
GPIO	on-chip	gpio
I2C0	on-chip	i2c
I2C1	on-chip	i2c
MPU	on-chip	arch/arm
NVIC	on-chip	arch/arm
PWM	on-chip	pwm
RADIO	on-chip	Bluetooth, ieee802154
RTC	on-chip	system clock
SPI	on-chip	spi
UART	on-chip	serial
USB	on-chip	usb
WDT	on-chip	watchdog

Other hardware features have not been enabled yet for this board.

Notably, this includes the PDM (microphone) interface.

Connections and IOs

The schematic [3] will tell you everything you need to know about the pins.

The I2C pull-ups are enabled by setting pin P1.00 high. This is automatically done at system init. The pin is specified in the zephyr,user Devicetree node as pull-up-gpios.

Programming and Debugging

This board requires the Arduino variant of bossac. You will not be able to flash with the bossac included with the zephyr-sdk, or using shumatech’s mainline build.

You can get this variant of bossac with one of two ways:

Building the binary from the Arduino source tree
Downloading the Arduino IDE
1. Install the board support package within the IDE
2. Change your IDE preferences to provide verbose logging
3. Build and flash a sample application, and read the logs to figure out where Arduino stored bossac.
4. In most Linux based systems the path is $HOME/.arduino15/packages/arduino/tools/bossac/1.9.1-arduino2/bossac.

Once you have a path to bossac, you can pass it as an argument to west:

west flash --bossac="<path to the arduino version of bossac>"

For example

west flash --bossac=$HOME/.arduino15/packages/arduino/tools/bossac/1.9.1-arduino2/bossac

On Windows you need to use the bossac.exe from the Arduino IDE [7] You will also need to specify the COM port using the –bossac-port argument:

west flash --bossac=%USERPROFILE%\AppData\Local\Arduino15\packages\arduino\tools\bossac\1.9.1-arduino2\bossac.exe --bossac-port="COMx"

Flashing

Attach the board to your computer using the USB cable, and then

west build -b arduino_nano_33_ble samples/basic/blinky

Double-tap the RESET button on your board. Your board should disconnect, reconnect, and there should be a pulsing orange LED near the USB port.

Then, you can flash the image using the above script.

You should see the red LED blink.

Debugging

You can debug an application on the board with a debug adapter that supports CMSIS-DAP. This board has the SWD connector for debugging but exposes it as a test pad pattern (not a connector) on the back side of the PCB. So, It needs bit of difficult soldering. At a minimum, SWDIO and SWCLK need soldering (As shown in the picture). GND, 3.3V, and RESET are also available in the DIP connector, therefore it may be easier to connect using the DIP connector instead of soldering to them.

After connecting the debug adapter, you can debug it the usual way. Type the following command will start debugging.

# From the root of the zephyr repository
west build -b arduino_nano_33_ble samples/basic/blinky
west debug

Debugging with TRACE32 (GDB Front-End)

Lauterbach provides GDB Debug version TRACE32 for Arduino Nano 33 BLE [4]. That license ties to Arduino Nano 33 BLE hardware serial number, it also works with the ZephyrRTOS.

Follow the instruction of the tutorial for Arduino Lauterbach TRACE32 GDB Front-End Debugger for Nano 33 BLE [5] to install the TRACE32.

After installing the TRACE32, You should set the environmental variable T32_DIR. If you installed TRACE32 into the home directory, run the following command. (It is a good idea to put in the login script.)

export T32_DIR="~/T32Arduino"

The TRACE32 is TRACE32 as GDB Front-End [6] version. Required to run the GDB server before launching TRACE32 with the following command.

west build -b arduino_nano_33_ble samples/basic/blinky
west debugserver

Execute the following command after launching the GDB server to run the TRACE32 and connect the GDB server.

west debug --runner=trace32 -- gdbRemote=:3333

The TRACE32 script handles arguments after the -- sign. You can set the following options.

Name	Required?	Description
gdbRemote	Required	Set the GDB server address or device file of the serial port. It can take <hostname>:<port> or <devicename>. e.g.) `gdbRemote=localhost:3333`, `gdbRemote=/dev/ttyACM0`
terminal	Optional	Set the device file of the serial port connected to the target console. e.g.) `terminal=/dev/ttyACM1`
userScript	Optional	Set user script that runs after system script execute done. e.g.) `userScript="./user.cmm"`