GEVINO Opto PNP

GEVINO Opto PNP is an affordable, Arduino-compatible industrial PLC built around the Microchip SAMD21 microcontroller (32-bit ARM Cortex-M0+). It is Arduino Zero compatible, so you program it with the standard Arduino IDE / Arduino SAMD core, while getting industrial-grade I/O: opto-isolated inputs, short-circuit-protected PNP outputs, analog inputs, an RS485 bus, an SD card slot and optional Ethernet / Wi-Fi / Bluetooth / RTC / cellular modem modules.

Designed and manufactured by GEVA Elettronica (Italy).

Looking to program the board? Jump to Quick start. Writing firmware with an AI coding assistant? Read AGENTS.md — the LLM/agent programming guide for this board.

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Highlights

• Arduino Zero compatible — program it with the Arduino IDE and the Arduino SAMD core.
• 11 dual-polarity opto-isolated inputs (positive or negative common).
• 4 short-circuit-protected PNP outputs, 40 V / 2.5 A, for resistive, inductive and capacitive loads.
• 2 analog inputs, 20 mA / 1 V / 10 V, 12-bit resolution.
• RS485 bus for parallel connection of up to 255 GEVINO devices, M-Bus or other.
• SD card slot and USB-C programming/debug port.
• Robust by design: protected against inductive loads, electrostatic discharge (ESD) and electromagnetic interference (EMI).
• Optional Ethernet, Wi-Fi, Bluetooth, RTC, RS232, RS485, cellular modem and CE certification.

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Technical specifications

General

Type	Industrial PLC, Arduino Zero compatible
Power supply, inputs and outputs	7 V – 40 V
Protection	Inductive loads, electrostatic discharge (ESD), electromagnetic interference (EMI)

Inputs / Outputs

• 11 opto-isolated inputs, positive or negative common (dual polarity).
• 4 short-circuit-protected PNP outputs, 40 V 2.5 A, for resistive, inductive and capacitive loads.
• 2 analog inputs: 20 mA / 1 V / 10 V, 12-bit resolution. (The two analog inputs can optionally be configured as digital NPN auxiliary outputs 5 and 6 via DIP switch.)
• 1 RS485 port for parallel connection of up to 255 GEVINO devices, M-Bus or other.

Front panel (behind the door)

• SD card slot
• Micro USB-C port
• LEDs for inputs, outputs, serial and power
• Reset button

Processor

• 32-bit ARM Cortex-M0+, 48 MHz (Microchip SAMD21)
• Flash memory 256 KB, RAM 32 KB

Optional modules

• Ethernet RJ45 module (Wiznet W5500)
• Wi-Fi ESP module (ESP8266)
• Bluetooth (SPP-C), RTC, RS232, cellular modem (SIM800/SIM808 class), CE certification

Update and debug

• Update GEVINO firmware over the Internet or from the SD card using a dedicated bootloader.
• Debug via Ethernet Telnet.
• Programming via Ethernet FTP (requires the bootloader on SD).

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Pinout / pin mapping

The board exposes its functions through named macros defined in src/gevino_opto_pnp_io.h. Pin numbers refer to the Arduino SAMD (Arduino Zero) numbering.

Opto-isolated inputs (active level)

Macro	Arduino pin		Macro	Arduino pin
In1	19 (A5)		In7	6
In2	38		In8	7
In3	2		In9	8
In4	3		In10	9
In5	4		In11	45
In6	5

In1 … In11 return true when the input is active (the macro already negates digitalRead).

Outputs

The 4 main outputs are PNP; the 2 optional auxiliary outputs (Out5/Out6, on the analog pins) are NPN.

Macro	Arduino pin	Type	Notes
Out1	A3	PNP
Out2	A4	PNP
Out3	42	PNP
Out4	27	PNP
Out5	A0 (Ana1)	NPN	Aux; only if enabled via DIP switch (Ana1_is_Output5)
Out6	A2 (Ana2)	NPN	Aux; only if enabled via DIP switch (Ana2_is_Output6)

Analog inputs

Macro	Arduino pin	analogPolling() result
Ana1	A0	analogResult[0]
Ana2	A2	analogResult[2]

System / bus pins

Macro	Arduino pin	Function
Rs485_TxEn	A1	RS485 transmit enable (half duplex)
SD_CS	12	SD card chip-select
ETH_CS	10	W5500 Ethernet chip-select
ETH_RES	11	W5500 Ethernet reset
LedRx_name	25	RX LED
LedTx_name	26	TX LED
LED_BUILTIN	—	yellow front LED

Serial ports

Port	Use
SerialUSB	USB-C native port — debug / programming console
Serial1	RS485 half-duplex bus (use set_Rs485_TxEn / res_Rs485_TxEn)
Serial	Bluetooth SPP-C module or Wi-Fi ESP8266 (AT commands), depending on the fitted module

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Repository contents

Path	Description
src/	The single-header support library (gevino_opto_pnp_io.h).
examples/	Ready-to-flash Arduino sketches.
docs/	Hardware manual (PDF), CE declaration and the enclosure-opening guide.
AGENTS.md	Programming guide for LLMs / AI coding agents.
llms.txt	LLM-friendly map of the repository (llmstxt.org convention).
keywords.txt	Arduino IDE syntax highlighting.
library.properties	Arduino library metadata.

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Requirements

• Arduino IDE (or arduino-cli).
• Arduino SAMD core ("Arduino SAMD Boards" / a core compatible with the GEVINO board).
• Select the board as Arduino Zero (Native USB Port).

The library is self-contained — it requires no external dependencies. It needs C++17 (the default on recent Arduino SAMD cores) because of the inline variables and functions in the header.

Installation

1. Download the ZIP from GitHub, or clone the repository.
2. In the Arduino IDE: Sketch → Include Library → Add .ZIP Library…
3. The examples then appear under File → Examples → GEVINO.

Quick start

#include "gevino_opto_pnp_io.h"   // the only include you need

void setup() {
  SerialUSB.begin(115200);        // USB-C debug console
  gevino_io_setup();              // configures all the board I/O (do NOT init pins yourself)
}

void loop() {
  if (In1) setOut1;               // mirror input 1 onto output 1
  else     resOut1;
}

Write non-blocking, state-based code (prefer switch/case, avoid delay() in loop()). See AGENTS.md for the full programming method, RS485/Modbus, Ethernet, SD and analog recipes.

API reference

Inputs

In1 … In11 — true when the input is active.

Digital outputs

• Read state: Out1 … Out4
• Set: setOut1 … setOut4
• Reset: resOut1 … resOut4
• Out5 / Out6 (setOut5, resOut5, setOut6, resOut6) are NPN auxiliary outputs, available only when enabled via DIP switch on Ana1/Ana2 (Ana1_is_Output5, Ana2_is_Output6).

LEDs and RS485

setLed / resLed (yellow front LED), setLedRx / resLedRx, setLedTx / resLedTx, set_Rs485_TxEn / res_Rs485_TxEn.

Functions

Function	Description
gevino_io_setup()	Configures pins, drive strength, LEDs, RS485 and resets the Ethernet module. Call it in setup().
testLeds()	LED / output power-up sequence for bench testing and photos.
analogEnable()	Starts the first non-blocking ADC conversion.
analogPolling()	Non-blocking analog read; updates analogResult[]. Call it often in loop().

Non-blocking ADC

analogPolling() avoids the multi-millisecond freeze of the standard analogRead(). Results land in analogResult[] (analogResult[0] = Ana1/A0, analogResult[2] = Ana2/A2). Advanced ADC configuration helpers (analogReadExtended, analogGain, analogReference2, analogCalibrate, analogPrescaler, analogReset, analogDifferential, …) are bundled in the same header.

Timer

A lightweight non-blocking software timer class (Timer) based on millis() is included — see the Timer example.

Examples

Example	What it shows
ADC	Non-blocking analog reading with analogPolling().
Timer	Non-blocking blink using the Timer class.
Aux_As_Output	Using the analog pins as NPN auxiliary outputs 5/6.
GEVINO_opto_PNP_Test	Full factory test: SD, RTC, FRAM, Ethernet, CAN, LoRa, ESP, SIM, inputs/outputs.

Documentation

The hardware manual and the CE declaration (PDF) are in docs/. See also Opening of GEVINO Opto — how to open the enclosure without snapping the fragile hooks (only needed for internal modifications; the SD card is reached from outside).

Buy / contact

GEVINO PLCs are designed and produced by GEVA Elettronica.

• Website: https://www.gevaelettronica.it
• Email: info@gevaelettronica.it

License

MIT — see LICENSE. The bundled SAMD21 ADC helpers are derived from Blake Felt's ATSAMD21_ADC and retain their original attribution in the source header.