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Arduino Logo.svg

This article applies to Arduino boards only.

See also: Multiplatform Programming Guide

Many Arduino projects have the need to send data to a PC running a program for data aquisition and visualisation. Lazarus is highly suitable for developing such programs, i.e. to build the PC-sided counterpart of an Arduino project.

For Lazarus developers Arduino opens a whole new world of smart physical sensors and actuators for monitoring, control and data acquisition.

The fpc compiler is even capable to compile programs for Arduino boards itself.

Arduino Uno R3.png

FPC on Arduino

Currently (2017) most Arduino boards carry microcontrollers of the AVR family (Atmega). An other popular arduino board carries a STM32 (ARM Cortex). For both microcontroller families there are fpc compilers available. Programming Arduino with FPC of course doesn't mean to use the arduino ecosystem with just a different language. Nevertheless arduino libs (C++) can be used in fpc programms, but mixing languages obviously is an advanced topic. While compilation the fpc creates a .hex-file (binary), this can be loaded to the microcontroller, arduino board respectively, using a programming software by choice. AVRDude e.g. also supports program upload using the Arduino bootloader.

There are further wiki pages for programing AVR microcontrollers: AVR, AVR Programming

There is also a tutorial on how to use Lazarus on a AtMega328p (Arduino Uno/Nano) in German language: AVR Embedded Tutorial/de

Communication between a Lazarus application and Arduino

The following section describes how your Lazarus/FPC application can communicate with Arduino boards, no matter whether fpc or arduino is running on the arduino board.

Serial communication

Here we show how to communicate with your board through serial communication channel.

Lazarus side serial application

There are many ways for serial communication in Lazarus and FPC.

Minimal Lazarus Synaser serial example

We will use Synaser from Synapse library in this example. Create Lazarus application with one form and two buttons. Include Synaser unit and add Synapse package as a new requirement to your project (you do this in Project Inspector). In OnClick event of both buttons put something like this:

procedure TForm1.Button1Click(Sender: TObject);
  ser: TBlockSerial;
  ser := TBlockSerial.Create;
    ser.Connect('COM1'); // write here Arduino COM port number (on linux it's something like '/dev/ttyUSB0')
    ser.config(9600, 8, 'N', SB1, False, False);
    ser.SendString('on'); // button 2 should have 'off' here

Arduino side serial application

You can program your Arduino in several languages.

Minimal Arduino C sketch serial example

You can follow this nice step by step tutorial. In short, you need to add a led with proper resistor to your input pin 13, compile this sketch in your Arduino IDE, and download it to your board:

int led = 13; // Pin 13

void setup()
    pinMode(led, OUTPUT); // Set pin 13 as digital out

    // Start up serial connection
    Serial.begin(9600); // baud rate

void loop()
    String input = "";

    // Read any serial input
    while (Serial.available() > 0)
        input += (char); // Read in one char at a time
        delay(5); // Delay for 5 ms so the next char has time to be received

        if (input == "on")
            digitalWrite(led, HIGH); // on
        else if (input == "off")
            digitalWrite(led, LOW); // off

Minimal Arduino mikroPascal serial example

mikroPascal for AVR can be used to develop Arduino programs. TBD.

Minimal Arduino E-Lab AvrCo serial example

E-Lab AvrCo Multitasking Pascal can be used to develop Arduino programs. TBD.

Minimal Arduino FPC serial example

Yes, your Arduino 8-bit AVR board can be programmed with FPC too. TBD.

Ethernet communication

Here we show how to communicate with your board through ethernet communication channel.

Lazarus side ethernet application


Arduino side ethernet application


Wiki Resources

External Resources