Processor; Wifi/Bt Communication Module - Arduino Nano 33 IoT Product Reference Manual

Ref. Description
Ref. Description
SJ1 Open solder bridge (VUSB)
TP Test points

3.2 Processor

The Main Processor is a Cortex M0+ running at up to 48MHz. Most of its pins are connected to the external
headers, however some are reserved for internal communication with the wireless module and the on-board
2
internal I C peripherals (IMU and Crypto).
NOTE: As opposed to other Arduino Nano boards, pins A4 and A5 have an internal pull up and default to be used
2
as an I C Bus so usage as analog inputs is not recommended.
Communication with NINA W102 happens through a serial port and a SPI bus through the following pins.
SAMD21 Pin SAMD21 Acronym
13 PA08
39 PA27
41 PA28
23 PA14
21 GPIO19
24 PA15
20 GPIO22
22 PA13
21 PA12
31 PA22
32 PA23

3.3 WiFi/BT Communication Module

Nina W102 is based on ESP32 and is delivered with a pre-certified software stack from Arduino. Source code for the
firmware is available [9].
NOTE: Reprogramming the wireless module's firmware with a custom one will invalidate compliance with radio
standards as certified by Arduino, hence this is not recommended unless the application is used in private
laboratories far from other electronic equipment and people. Usage of custom firmware on radio modules is the
sole responsibility of the user.
Some of the module's pins are connected to the external headers and can be directly driven by ESP32 provided
SAMD21's corresponding pins are aptly tri-stated. Below is a list of such signals:
SAMD21 Pin SAMD21 Acronym
48 PB03
14 PA09
8 PB09
7 PB08
8 / 18
Ref.
Ref.
SJ4
xx
NINA Pin
19
27
7
28
UART RTS
29
UART CTS
1
36
23
22
NINA Pin
8
5
31
35
Arduino® Nano 33 IoT / Rev. 01 - 06/12/2021
Arduino® Nano 33 IoT
Description
Description
Closed solder bridge (+3V3)
Lorem Ipsum
NINA Acronym
RESET_N
GPIO0
GPIO33
GPIO5
GPIO18
GPIO21
GPIO12
GPIO3
GPIO1
NINA Acronym
GPIO21
GPIO32
GPIO14
GPIO13
Description
Reset
Attention Request
Acknowledge
SPI CS
SPI CLK
SPI MISO
SPI MOSI
Processor TX Nina RX
Processor RX Nina TX
Description
A7
A6
A5/SCL
A4/SDA