Wiznet makers

What the Project Does

The RFXCOM RFX series communicates with various field devices such as RF sensors, blinds, lights, meters, fans, and motor control devices. The device receives or transmits RF messages and delivers them in a format that can be used by RFXmngr, Home Assistant, Domoticz, or MQTT-based automation systems.

The RFX-433EMC uses the 433 MHz band, while the RFX-868 uses the 868 MHz band. Depending on the firmware configuration, the device can operate through USB, Wi-Fi, W5500 LAN, or MQTT. When operating over LAN or Wi-Fi, the RFXCOM protocol uses TCP port 10001.

In Industrial IoT or commercial building automation, this device can be viewed as an RF-to-IP gateway. Field RF devices communicate with the RFX transceiver, the RFX firmware processes the protocol, and data is then delivered to a server or automation platform through the W5500 LAN path.

Image source: AI-generated

Image source: rfxcom.com

Where WIZnet Fits

The WIZnet product used in this configuration is the W5500 Ethernet Controller. The W5500 connects to the RFX board over SPI and provides a wired Ethernet interface.

The DIY wiring shown in the document is as follows.

W5500  ->  RFX
3V3    ->  3V3
GND    ->  GND
MISO   ->  37
MOSI   ->  35
SCLK   ->  36
SCS    ->  39
RST    ->  40
INT    ->  41

In this wiring configuration, the W5500 is not a simple external LAN adapter. It is an Ethernet controller directly controlled by the RFX board. In addition to the SPI data lines, chip select, reset, and interrupt signals are also used, so the quality of the board-level connection directly affects LAN stability.

The W5500 is an Ethernet controller with an embedded hardware TCP/IP stack. It provides an integrated MAC/PHY, 32 KB internal buffer, and 8 hardware sockets, allowing the main firmware to implement wired networking without handling the full TCP/IP stack in software.

Image source: rfxcom.com

Implementation Notes

The available material is a user guide PDF, and the actual RFXCOM firmware source code is not publicly available. Therefore, the W5500 initialization code or socket handling loop cannot be verified. The verifiable scope is limited to hardware connections, firmware operation method, TCP port usage, configuration procedure, and debugging method.

The overall structure can be summarized as follows.

RFX-433EMC / RFX-868
  ├─ RF transceiver
  │   ├─ RFX-433EMC: 433 MHz
  │   └─ RFX-868: 868 MHz
  ├─ USB-C
  │   ├─ Power supply
  │   ├─ Firmware update
  │   ├─ Debug message monitoring
  │   └─ Recovery command execution
  ├─ W5500 LAN
  │   ├─ SPI-based Ethernet connection
  │   ├─ Uses TCP port 10001
  │   └─ Supports up to 2 simultaneous connections
  └─ Host system
      ├─ RFXmngr
      ├─ Home Assistant / Domoticz
      └─ MQTT-based automation system

LAN configuration is not performed by directly modifying W5500 registers. Instead, the RFX device is connected over USB, debug messages are checked through a terminal, and the user accesses the device IP address in a browser to configure the hostname, local IP, subnet mask, and gateway.

For commercial installations, a static IP configuration is more suitable than DHCP. The automation server must always be able to find the device at the same address, and a fixed IP also makes troubleshooting easier during field maintenance.

Practical Tips / Precautions

Check the supported model first. The W5500 LAN option is described for the RFX-433EMC or RFX-868.

Make sure the 3.3 V power orientation is correct. Since the W5500 operates on 3.3 V, incorrect power pin connection may damage the board.

Using a static IP is recommended. In commercial automation environments, it is important that the device IP address does not change.

LAN debugging is performed through the USB terminal. During setup, it is recommended to keep the USB connection active and monitor the status messages.

A blinking red LED indicates a LAN connection problem. Check the cable, switch port, power, and W5500 installation status first.

Enable only the RF protocols that are required. Disabling unused receive protocols can help improve RF reception stability.

FAQ

Q: Why use the W5500?
A: The W5500 adds a stable wired Ethernet connection to the RFX device. Since it uses a hardware TCP/IP stack, it reduces network processing load on the embedded device and enables a more predictable field network configuration than Wi-Fi.

Q: How is the W5500 connected to the RFX board?
A: It is connected over SPI. MISO, MOSI, SCLK, SCS, RST, INT, 3.3 V, and GND are required.

Q: What is the role of the W5500 in this project?
A: The W5500 acts as the network interface that transfers RFXCOM protocol data over wired LAN. The host application connects to the device’s local IP address and TCP port 10001.

Q: Can beginners follow this project?
A: This is not a complete beginner-level task. The user needs to open the enclosure, identify board pins, and have basic knowledge of SPI wiring, USB terminals, and IP configuration.

Q: Why use W5500 LAN instead of Wi-Fi?
A: Wi-Fi is easier to install, but it requires consideration of wireless interference, AP settings, and connection failure states. W5500 LAN requires wiring, but it provides a stable wired access point based on a fixed IP address, making it more suitable for Industrial IoT and commercial automation environments.