ioNIC Loopback Arduino Guide

This guide explains how to control the W55RP20-S2E module using a Raspberry Pi Pico and implement network loopback functionality.

COMPONENTS Hardware components

Raspberry Pi - Raspberry Pi Pico

x 1

Software Apps and online services

Arduino - Arduino IDE

x 1

PROJECT DESCRIPTION

How to Run Loopback Example

This project uses the Raspberry Pi Pico as the main controller to operate the W55RP20-S2E module. Connect to the W55RP20-S2E module via SPI or UART communication to implement TCP Client, TCP Server, and UDP Loopback functionality.

Supported Communication Methods:

SPI Communication
UART Communication

Supported Loopback Modes:

TCP Client Loopback
TCP Server Loopback
UDP Loopback

Step 1: Prepare Software

Download and install the following software:

Required Software:

Step 2: Hardware Connections

2.1 SPI Mode Connection

When controlling the W55RP20-S2E module via SPI, connect as follows:

Raspberry Pi Pico	W55RP20-S2E Module	Description
GP4 (SPI0 RX/MISO)	GP3 (SPI_MISO)	Master In Slave Out
GP3 (SPI0 TX/MOSI)	GP4 (SPI_MOSI)	Master Out Slave In
GP2 (SPI0 SCK)	GP2 (SPI_SCK)	Clock Signal
GP5 (SPI0 CSn)	GP5 (SPI_CSn)	Chip Select
GP13	GP13 (SPI_INT)	SPI Master Recv data pending pin
GP26	GP26 (UART_SPI_SEL)	UART/SPI interface select pin (High:SPI, Low/NC:UART)
3.3V	3V3	Power Supply
GND	GND	Ground

2.2 UART Mode Connection

When controlling the W55RP20-S2E module via UART:

Raspberry Pi Pico	W55RP20-S2E Module	Description
GP4 (UART1 TX)	GP5 (UART1 RX)	Pico TX → Module RX
GP5 (UART1 RX)	GP4 (UART1 TX)	Pico RX → Module TX
GND	GND	Ground
3.3V	VCC/3V3	Power Supply

Step 3: Arduino IDE Setup

Install Board Support Package

Open Arduino IDE
Go to File → Preferences
Add the following to "Additional Boards Manager URLs": https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json
Go to Tools → Board → Boards Manager
Search for "Raspberry Pi Pico" and install Raspberry Pi Pico/RP2040 by Earle F. Philhower, III
Select Tools → Board → Raspberry Pi RP2040 Boards → Raspberry Pi Pico

Step 4: Code Examples

Each example provides a .ino file to upload to the Pico.

SPI Communication

2. UART Communication

Step 5: Upload and Test

5.1 Select Raspberry Pi Pico

Go to Tools → Board → Raspberry Pi RP2040 Boards → Raspberry Pi Pico
Select Tools → Port → Choose your COM port

5.2 Upload Code

Open the desired example .ino file
Modify IP addresses and port numbers as needed

TCP Server

  void setup() {
  ... 
  at_set("LI192.168.11.2"); // Local IP
  at_set("SM255.255.255.0");
  at_set("GW192.168.11.1");
  at_set("DS8.8.8.8");
  at_set("LP5000");         // Local port
  ...
  }

TCP Client

void setup() {

...
  at_set("LI192.168.11.2"); // Local IP
  at_set("SM255.255.255.0");
  at_set("GW192.168.11.1");
  at_set("DS8.8.8.8");
  at_set("RH192.168.11.100"); // Remote host (server)
  at_set("RP5000");         // Remote port

...
}

void setup() {
... 
  at_set("OP3");            // UDP mode
  at_set("LI192.168.11.2"); // Local IP
  at_set("SM255.255.255.0");
  at_set("GW192.168.11.1");
  at_set("DS8.8.8.8");
  at_set("LP5000");         // Local port
  at_set("RH192.168.11.100"); // Remote host for UDP echo
  at_set("RP5000");         // Remote port
  ...
}

3. Click Upload button or press Ctrl+U

4. Wait for upload to complete