---
title: "ATXmegaWiznet_module"
url: "https://maker.wiznet.io/Grace_Koo/projects/atxmegawiznet-module/"
markdown_url: "https://maker.wiznet.io/Grace_Koo/projects/atxmegawiznet-module/md"
type: "UCC: User Created Content"
author: "Grace"
author_url: "https://maker.wiznet.io/Grace_Koo/"
original_author: "Grace Koo"
original_url: "https://github.com/marekw1986/ATXmegaWiznet_module.git"
published: "2025-12-09"
language: "en"
hardware: ["WIZnet W5500"]
likes: 0
views: 335
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# ATXmegaWiznet_module

> ATXmega + Wiznet IoT module with MQTT, DHCP, SNTP & SD logging. Production-ready network data logger for Ham radio and industrial use.

Original author: Grace Koo (source: https://github.com/marekw1986/ATXmegaWiznet_module.git)

## Components

- **WIZnet W5500** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5500))

WIZnet parts: W5500 ([Datasheet](https://docs.wiznet.io/Product/Chip/Ethernet/W5500/datasheet?utm_source=maker&utm_medium=project&utm_campaign=w5500), [product hub](https://maker.wiznet.io/products/w5500/))

## Documents and links

- [GitHub: ATXmegaWiznet_module](https://github.com/marekw1986/ATXmegaWiznet_module.git) (code)

## Article

** All images in this article were generated by Gemini.*

## ATXmega W5500 Module Project

![](https://maker.wiznet.io/upload/ckeditor5/201746494%5F1765470483%2Epng)

An IoT-ready network data logger built with the ATXmega128A3U MCU and **WIZnet W5500** Ethernet chip.
By utilizing the W5500’s hardware TCP/IP engine, the system delivers stable and efficient network connectivity even on a lightweight 8-bit MCU.

---

### Project Overview

- Author: marek (marekw1986)

- Platform: ATXmega128A3U + **WIZnet W5500**

- Purpose: MQTT-based remote monitoring and data logging

---

### Key Hardware Components

![](https://maker.wiznet.io/upload/ckeditor5/201746494%5F1765470562%2Epng)

- MCU: ATXmega128A3U running at 32 MHz

- Ethernet: **WIZnet W5500 (hardware TCP/IP stack)**

- Storage: SD card with FatFS

- User I/O: 3 LEDs, 3 buttons

- UART Debug Output: 115200 baud

- Communication: SPI bus for both W5500 and SD card

The W5500’s dedicated TCP/IP offload engine enables reliable network operation without consuming MCU resources, making it ideal for ATXmega-class devices.

---

### Development Environment

- IDE: MPLAB X

- Compiler: AVR-GCC

- Programmer: AVRISP mkII

- Flash command:

```plaintext
avrdude -p x128a3u -c avrispmkII -P usb -U flash:w:code.debug.elf
```

---

### Core Features

![](https://maker.wiznet.io/upload/ckeditor5/201746494%5F1765470578%2Epng)

#### 1. Network Communication (via W5500)

- DHCP automatic IP assignment

- MQTT messaging

- SNTP time synchronization (hourly)

#### 2. Data Storage

- FatFS-based SD card filesystem

- Automatic logging to **test.txt** every 10 seconds

- Local data backup even during network outages

#### 3. System Management

- 200 ms watchdog timer for autonomous recovery

- RTC combined with SNTP for precise timestamps

- UART debug messages for diagnostics

#### 4. User Interface

- LED indicators (1 s / 2 s / 4 s blink patterns)

- Three pull-up buttons for interaction

---

### Project Highlights

- **W5500 hardware TCP/IP stack minimizes MCU load**

- Stable simultaneous operation of DHCP, MQTT, and SNTP

- Local SD card logging for long-term data retention

- Automatic time alignment through SNTP

- Robust long-term operation with watchdog and reconnect logic

- Modular source structure for easy maintenance

---

### Possible Applications

### ![](https://maker.wiznet.io/upload/ckeditor5/201746494%5F1765470027%2Epng)

- **Ham Radio telemetry with MQTT forwarding**

- **IoT sensor nodes with local data backup**

- **Network event data loggers**

- **Industrial equipment monitoring**

---

### Conclusion

This project showcases how the ATXmega128A3U paired with the **WIZnet W5500** can deliver a compact, reliable IoT data logging solution.
With MQTT connectivity, SNTP synchronization, SD card logging, and resilient system management, it is suitable for real-world embedded applications.
It also serves as an excellent reference design for developers exploring W5500-based IoT systems.

---

Source: https://maker.wiznet.io/Grace_Koo/projects/atxmegawiznet-module/