---
title: "How to change the GPIO of the UART used by Wizfi360 under the Arduino platform?"
url: "https://maker.wiznet.io/forum/15114"
markdown_url: "https://maker.wiznet.io/forum/15114/md"
type: "Forum topic"
category: "General"
author: "gavinchang"
created: "2024-01-11T02:41:13+09:00"
last_activity: "2024-01-11T02:45:18+09:00"
language: "en"
views: 167
replies: 0
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# How to change the GPIO of the UART used by Wizfi360 under the Arduino platform?

## Question

Asked by gavinchang on 2024-01-11 in General.

On the arduino platform, if you are not using the default GPIO of UART used by the Wizfi360 library, you need to change the definition of GPIO. There are two methods:
Method 1: Change the IO definition of the board. Taking wizfi360_evb_pico as an example, its IO configuration file is located at:
C:\Users\(uaername)\AppData\Local\Arduino15\packages\rp2040\hardware\rp2040\2.6.1\variants\wiznet_wizfi360_evb_pico\pins_arduino.h
You can change the GPIO definition of UART by changing the definition:

```
//Serial
// #define PIN_SERIAL1_TX (0u)
// #define PIN_SERIAL1_RX (1u)

#define PIN_SERIAL1_TX (4u)
#define PIN_SERIAL1_RX (5u)
```

This method is also suitable for W5100S_EVB_PICO. The changed file path is:
C:\Users\(uaername)\AppData\Local\Arduino15\packages\rp2040\hardware\rp2040\2.6.1\variants\wiznet_w5100s_evb_pico\pins_arduino.h

Method 2: Use the software serial port. If the IO used is not the GPIO of the hardware UART, you can only use the software serial port. You need to add the <SoftwareSerial.h> library.
And define GPIO through the following method,

```
   SoftwareSerial SerialUart(3, 2); // IO3 for RX & IO2 for RX
   SerialUart.begin(2000000);
   WiFi.init(&SerialUart);
```

---

Source: https://maker.wiznet.io/forum/15114