Arduino Nano is back with WiFi ! – Nano 33 IoT

The Nano form factor has been a crowd-pleaser amongst makers for years due to its small footprint and ease of integration into any project. As announced at Maker Faire Bay Area, the Nano 33 IoT is part of the new 3.3V variant of the family with an Arm Cortex-M0+ microcontroller and a pre-certified ESP32-based WiFi and Bluetooth module from u-blox that brings sophisticated connectivity to its tiny package. The inclusion of an ECC608A crypto chip means it also offers IoT security features not usually available at such a low price point.

Today, we sat down with Dario Pennisi, Arduino hardware and firmware development manager, to learn more about the Nano 33 IoT.

Key Features

  1. Secure WiFi and Bluetooth connectivity with a 6-axis IMU.
  2. Pre-certified module with an external processor ensures maintaining RF compliance when writing application code versus ESP32 modules where modifying code impacts certification.
  3. On-board DC-DC power supply enables the board to be powered up to 21V maintaining high efficiency and offering a lot of current to external devices without overheating. This is a big improvement over other products on the market that have LDO and heat up quite a bit when powered at high voltages.



Applications

  1. Add WiFi and Bluetooth connectivity with strong security to all the existing Arduino Nano applications.
  2. On-board IMU can be used to wirelessly monitor vibration, orientation, and rotational speed of small objects thanks to its lightweight and compact form factor.
  3. Run directly from high voltages from lead or multi-cell Lithium-ion batteries providing 3.3V power supply to peripherals at significant output current.

Which Arduino board is the most similar to the Nano 33?

The Nano 33 IoT is essentially a MKR WiFi 1010, but sacrifices a battery charger and shield compatibility in favor of a miniaturized footprint (45×18 mm) and lower cost. The Nano 33 IoT is built around the ESP32, which is primarily aimed at WiFi but supports Bluetooth as well, although with higher power consumption than the Nano 33 BLE.



TECH SPECS

This board is based on the SAMD21G18A microcontroller.

Clock up to 48MHz
Flash 256KB
SRAM 32KB

Please note: Arduino Nano 33 IoT only supports 3.3V I/Os and is NOT 5V tolerant so please make sure you are not directly connecting 5V signals to this board or it will be damaged. Also, as opposed to Arduino Nano boards that support 5V operation, the 5V pin does NOT supply voltage but is rather connected, through a jumper, to the USB power input. To avoid such risk with existing projects, where you should be able to pull out a Nano and replace it with the new Nano 33 IoT, we have the 5V pin on the header, positioned between RST and A7 that is not connected as the default factory setting. This means that if you have a design that takes 5V from that pin, it won’t work immediately, as a precaution we put in place to draw your attention to the 3.3V compliance on digital and analog inputs. 5V on that pin is available only when two conditions are met: you make a solder bridge on the two pads marked as VUSB and you power the NANO 33 IoT through the USB port. If you power the board from the VIN pin, you won’t get any regulated 5V and therefore even if you do the solder bridge, nothing will come out of that 5V pin. The 3.3V, on the other hand, is always available and supports enough current to drive your sensors. Please make your designs so that sensors and actuators are driven with 3.3V and work with 3.3V digital IO levels. 5V is now an option for many modules and 3.3V is becoming the standard voltage for electronic ICs. The communication on WiFi and Bluetooth is managed by a NINA W102 ESP32 based module. The module is connected to the SAMD21 microcontroller with an SPI BUS and a serial port through the following pins:

SAMD21 Pin SAMD21 Acronym NINA Pin NINA Acronym Description
13 PA8 19 RESET_N Reset
39 PA27 27 GPIO0 Attention Request
41 PA28 7 GPIO33 Acknowledge
23 PA14 28 / 21 GPIO5 / GPIO19 SPI CS / UART RTS
24 PA15 29 / 20 GPIO18 / GPIO22 SPI CLK / UART CTS
22 PA13 1 GPIO21 SPI MISO
21 PA12 36 GPIO12 SPI MOSI
31 PA22 23 GPIO3 Processor TX -> Nina RX
32 PA23 22 GPIO1 NINA TX -> Processor RX

Some of the NINA W102 pins are connected to the 15+15 pins headers/pads and can be directly driven by the module’s ESP32; in this case, it is necessary that the SAMD21 corresponding pins are aptly tri-stated. Below is a list of such signals:

SAMD21 Pin SAMD21 Acronym NINA Pin NINA Acronym Description
48 PB03 8 RESET_N A7
14 PA09 5 GPIO0 A6
8 PB09 31 GPIO33 A5/SCL
7 PB08 35 GPIO5 / GPIO19 A4/SDA

The IMU is a LSM6DSL and it is managed through I2C. The crypto chip is an ATECC608A and has a supporting library that is used by the WiFiNINA library. The board has a two 15 pins connectors – one on each side -,  pin to pin compatible with the original Arduino Nano.



Pin Function Type Pin Description
1 D13 Digital GPIO
2 +3V3 Power Out Internally generated power output to external devices
3 AREF Analog Analog Reference; can be used as GPIO
4 A0/DAC0 Analog ADC in/DAC out; can be used as GPIO
5 A1 Analog ADC in; can be used as GPIO
6 A2 Analog ADC in; can be used as GPIO
7 A3 Analog ADC in; can be used as GPIO
8 A4/SDA Analog ADC in; I2C SDA; Can be used as GPIO (*)
9 A5/SCL Analog ADC in; I2C SCL; Can be used as GPIO(*)
10 A6 Analog ADC in; can be used as GPIO
11 A7 Analog ADC in; can be used as GPIO
12 VUSB Power In/Out Normally NC; can be connected to
VUSB pin of the USB connector by shorting a jumper
13 RST Digital In Active low reset input (duplicate of pin 18)
14 GND Power Power Ground
15 VIN Power In Vin Power input
16 TX Digital USART TX; can be used as GPIO
17 RX Digital USART RX; can be used as GPIO
18 RST Digital Active low reset input (duplicate of pin 13)
19 GND Power Power Ground
20 D2 Digital GPIO
21 D3/PWM Digital GPIO; can be used as PWM
22 D4 Digital GPIO; can be used as PWM
23 D5/PWM Digital GPIO; can be used as PWM
24 D6/PWM Digital GPIO
25 D7 Digital GPIO
26 D8 Digital GPIO
27 D9/PWM Digital GPIO; can be used as PWM
28 D10/PWM Digital GPIO; can be used as PWM
29 D11/MOSI Digital SPI MOSI; can be used as GPIO
30 D12/MISO Digital Digital SPI MISO; can be used as GPIO

(*) As opposed to other Arduino Nano boards, pins A4 and A5 have an internal pull-up and default to be used as an I2C Bus so usage as analog inputs is not recommended. Opposed to Arduino Nano boards that support 5V operation, the 5V pin does NOT supply voltage but is rather connected, through a jumper, to the USB power input. On the bottom side of the board, under the communication module, debug signals are arranged as 3×2 test pads with 100 mil pitch. Pin 1 is the bottom left one with the USB connector on the left and the test pads on the right

Pin Function Type Pin Description
1 +3V3 Power Out Internally generated power output to be used as voltage reference
2 SWD Digital SAMD11 Single Wire Debug Data
3 SWCLK Digital In SAMD11 Single Wire Debug Clock
4 UPDI Digital ATMega4809 update interface
5 GND Power Power Ground
6 RST Digital In Active low reset input

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