Wiznet makers

📌 A DIN-Rail Stepper PLC Where Ethernet Is a Plug-In W5500 Module

GEVA Elettronica is a small electronics manufacturer in Almese, outside Torino, Italy, whose about page opens with "Geva is a small company founded in 1993, born from the desire to combine passion, innovation, and quality of life" and names founder Giorgio Evangelista as the designer at the helm. The company builds access control and hotel automation systems plus a family of Arduino-compatible PLCs called GEVINO, sold from its own store at shop.gevaelettronica.it.

The GEVINO Motor is the motor-control member of that family: a DIN-rail PLC built on a Microchip SAMD21 (Arduino Zero compatible) with a Toshiba TB67S128FTG driver that runs one stepper or two brushed DC motors at up to 50 V and 5 A per phase. Wired networking is not on the base board. Ethernet arrives as a separately purchased plug-in module, and the vendor's own manual identifies it in three words: "Ethernet module: W5500 chip" (GEVINO Motor v1.0 Manual, page 7). With that module fitted, a EUR 74.80 stepper controller gains Modbus TCP, a Telnet debug console and FTP firmware loading.

The GEVINO Motor on a 35 mm DIN rail with an Ethernet cable fitted. Photo: GEVA Elettronica shop, letterboxed to 4:3 for this card.

Vendor, Availability, and Price

The legal manufacturer on the CE declaration inside the GitHub repository is "GEVA di evangelista giorgio", Via Navili 1, 10040 Almese (TO), Italy, and the same address and phone number (011 935 2635) appear in the store footer. The declaration covers EMC directive 2014/30/UE and RoHS under EN 61000-6-2:2019 and EN 61000-6-4:2019, the industrial immunity and emission standards, and it is a manufacturer self-declaration rather than third-party certification.

On 28 August 2026 the store listed the GEVINO Motor at EUR 74.80 under SKU GEVA-MOTORE and EAN 0687848194063, in stock with 87 units of the default build and 286 units across all versions, with the offer marked valid until 12 September 2026. The page's embedded pricing data records EUR 74.80 as a tax-excluded figure, with Italian IVA at 22 percent listed separately, and volume pricing drops the unit to EUR 72.93 at five pieces and EUR 71.06 at ten. The buying path is a direct cart purchase, not a request for quote.

That EUR 74.80 buys the base configuration: the board in the default 22.5 mm green enclosure, with no network module. The store sells the enclosure in three thicknesses, a slim 17.5 mm black case for the bare board, the 22.5 mm green case sized for accessories such as Ethernet, RTC, Wi-Fi and Bluetooth, and a 35 mm black case for RS232 or a Li-Po battery. The accessories category lists a CE-marked "Ethernet Module v2" built on the W5500 at EUR 15.00, with 70 units in stock on the same date; that accessory page is worded for the GEVINO Opto and Civile boards, and the Motor page itself does not link a Motor-specific Ethernet SKU, so a buyer should confirm the module choice with GEVA when ordering.

What the Base Board Does Before Any Network Is Fitted

The board pairs the 48 MHz SAMD21 (256 KB flash, 32 KB RAM) with the TB67S128FTG over SPI at up to 24 MHz, giving constant-current control, microstepping from full step down to 1/128, ADMD (Advanced Dynamic Mixed Decay) and anti-stall. The manual states maximum step rates of 90 kHz microsteps per second with the library's own MicrostepUp command and 58 kHz through AccelStepper setSpeed(), both at 24 MHz SPI.

The PLC beside the class of motor it drives, one stepper or two brushed DC. Vendor photo, cropped to remove a store banner overlay.

Around the motor core sit industrial I/O: 5 PNP inputs, 4 short-circuit-protected PNP outputs rated 40 V 2.5 A, and 3 analog inputs jumper-selectable between 10 V, 1 V and 20 mA ranges at 12 bits, plus two ADC channels that read the motor phase currents. An RS485 half-duplex bus connects up to 255 GEVINO devices in parallel (vendor figure), and a front door hides a micro-SD slot, USB-C port, status LEDs and reset button. Supply is 7 to 40 V for logic and 7 to 44 V for the motor, over a working range of -40 to +85 degrees Celsius.

The LED legend behind the front window, with the RJ45 socket of the Ethernet option occupied. Photo: GEVA Elettronica shop.

⚙️ Where the W5500 Sits: Chip-Select 10 on a Crowded SPI Bus

The store product page never mentions W5500 or WIZnet; every chip-level fact lives in the GitHub repository github.com/geva-elettronica/GEVINO-Motor, published in a single commit on 9 June 2026 under the MIT license. The README lists "Ethernet RJ45 module (Wiznet W5500)" among the optional modules, the manual's page 2 pin map marks the module footprint "Ethernet W5500 eth SPI + D11 + D10", and the library header src/gevino_motor.h fixes the pins as ETH_CS = 10 and ETH_RES = 11.

Page 2 of the v1.0 manual (revision "Manual v2") with the W5500 module footprint drawn on the board outline. Diagram: GEVA Elettronica.

The board initialization routine is W5500-aware even before any network code runs: gevino_motor_setup() pulses ETH_RES low for 300 ms and back high, so a fitted module always starts from a clean reset. The programming guide then keeps the software story deliberately standard, two lines from AGENTS.md:

#include <Ethernet.h>
Ethernet.init(ETH_CS);   // ETH_CS = 10, defined in gevino_motor.h

Because the firmware uses the stock Arduino Ethernet library, TCP and UDP run on the W5500's hardwired protocol sockets rather than a software stack in the SAMD21's 32 KB of RAM. The factory test sketch examples/GEVINO_motor/GEVINO_motor.ino, whose header carries the date 22/08/2020 and Giorgio Evangelista's name, brings the port up with Ethernet.begin(mac) and starts an EthernetServer on port 80 alongside stepper, RS485, SD, RTC, CAN and LoRa tests. For fieldbus work, AGENTS.md prescribes ArduinoModbus over Ethernet for Modbus TCP, while the README adds "Debug via Ethernet Telnet", "Programming via Ethernet FTP" and program updates over the Internet through a dedicated SD-card bootloader.

The one real constraint is bus sharing. The W5500 is one of several peripherals on the single SAMD21 SPI bus, and the option modules overlap on the same two pins:

Ethernet, CAN and LoRa all claim D10 and D11, so the board carries one of the three at a time. An ESP Wi-Fi or Bluetooth module rides the separate Serial port instead, but no vendor document shows wired and wireless networking operating together.

Generated technical diagram: the shared SPI bus and the network features the EUR 15.00 W5500 option adds. Pin data from gevino_motor.h and manual pages 2, 5 and 7.

A Vendor Repository Written for AI Coding Agents

The repository is unusual for a small industrial vendor: besides the single-header library and eleven sine tables for microstepping, it ships an AGENTS.md programming guide addressed explicitly to "LLMs and AI coding agents (Claude Code, Cursor, Copilot, etc.)" and an llms.txt index following the llmstxt.org convention. The guide encodes house rules, non-blocking state-machine code, one translation unit, no manual pin init, and spells out the same two-line Ethernet.init(ETH_CS) recipe for the W5500 module.

The Ethernet section of AGENTS.md as rendered on GitHub, captured 28 August 2026. Screenshot: github.com/geva-elettronica/GEVINO-Motor.

The product itself predates the repository by years, as the 2020 date in the factory test sketch shows; what happened on 9 June 2026 is that GEVA published its whole controller family on GitHub in one sweep, each repo with the same AGENTS.md treatment. As of 28 August 2026 the GEVINO-Motor repo stands at 5 stars with no issues yet, so the value today is documentation depth rather than community traction.

One Optional W5500 Across the Whole GEVINO Family

The same Ethernet design repeats across the family, each time verifiable in that product's own README on the geva-elettronica GitHub account:

For WIZnet readers the pattern is the takeaway: one Italian vendor standardized a low-cost W5500 add-on as the wired-network path for four different Arduino-compatible controllers, always on plain SPI with the stock Ethernet library, and now documents that choice in machine-readable form for AI coding assistants.

Where It Fits, and What Is Not Published

The GEVINO Motor suits machine axes, pumps, gates and lab automation where a stepper needs industrial I/O and a network drop more than it needs a full-size PLC rack. Positioned against configurable smart relays of a similar price class, its differentiators are the 1/128 microstepping driver and the fact that the entire programming surface is the open Arduino ecosystem, with OpenPLC and Cursor named as supported workflows on the store page.

The honest gaps: Ethernet is not standard equipment, the store page does not name the W5500 (the GitHub repo and manual do), schematics are not published, and no independent review or field report of the Motor could be found as of 28 August 2026. The CE declaration is self-issued, and the RS485 fan-out and step-rate figures are vendor numbers.

Related WIZnet Maker Projects

GEVINO Civile: Ethernet Smart Building Controller covers the building-automation sibling from the same GitHub publication wave; the Civile switches relays and reads room sensors, while the Motor board profiled here is a different product that adds the TB67S128FTG power stage for motion.

GEVINO Opto is the earlier general-purpose GEVINO PLC on the Maker site; it shares the enclosure system and the same W5500-on-D10 Ethernet option, and shows how long the family has been in GEVA's catalog.

STM32F103 Multi-Axis Motion Controller with W5500 Ethernet and Industrial I/O solves the same motion-plus-Ethernet problem as an open hardware board; it integrates the W5500 permanently instead of as an option, which makes a useful contrast in system partitioning.

How Does Senbrino Turn AI-Edited Ladder Logic Into an Arduino Sketch on a W5500 PLC Board? approaches AI-assisted PLC programming from the toolchain side; GEVA approaches it from the documentation side with AGENTS.md and llms.txt, and both land on Arduino code driving a W5500.

❓ FAQ

Q. Does the GEVINO Motor ship with the W5500 Ethernet port on board? No. The EUR 74.80 base price covers the PLC in its default 22.5 mm green enclosure without any network module, and the W5500 Ethernet module is a separately purchased option that the green enclosure is sized to accept.

Q. Where is the W5500 documented, since the store page never mentions it? In the vendor's own GitHub repository: the manual states "Ethernet module: W5500 chip" on page 7, the page 2 pin map labels the footprint "Ethernet W5500 eth SPI + D11 + D10", and the README lists "Ethernet RJ45 module (Wiznet W5500)".

Q. How does firmware talk to the W5500 module? Through the standard Arduino Ethernet library with Ethernet.init(ETH_CS) on chip-select 10, so TCP and UDP sockets run in the W5500 hardware. The factory test sketch serves HTTP from EthernetServer on port 80, and AGENTS.md recommends ArduinoModbus for Modbus TCP.

Q. Can the Ethernet module be combined with LoRa or CAN on the same board? No. The W5500, the MCP2515 CAN controller and the RA02 LoRa radio all use D10 for chip-select and D11 for reset or interrupt, so only one of the three fits at a time. ESP Wi-Fi and Bluetooth modules use the separate Serial port.

Q. What motors can the TB67S128FTG driver actually run? One stepper motor or two brushed DC motors, at constant current up to 50 V and 5 A per phase with 10 A peak, microstepping down to 1/128 step, with ADMD decay control and anti-stall built into the driver.