Céu-Arduino supports the development of Arduino applications in the programming language Céu:

• Source Code: https://github.com/ceu-lang/ceu-arduino/

• Chat: https://gitter.im/fsantanna/ceu

Arduino Arduino is an open-source project that created microcontroller-based kits for building digital devices and interactive objects that can sense and control physical devices.

Céu is a reactive language that aims to offer a higher-level and safer alternative to C:

• Home Page: http://www.ceu-lang.org/
• Source code: https://github.com/ceu-lang/ceu/

Céu-Arduino empowers the development of Arduino applications with the following extensions:

• Awaiting events in direct/sequential style.
• Parallel lines of execution with
  • safe abortion;
  • deterministic behavior (in contrast with threads).
• Asynchronous loops for heavy computations.
• Interrupt-driven operation mode (optional and experimental).
• Seamless integration with standard Arduino (e.g., analogRead, random, etc).

Install

Install Arduino

Requires arduino-1.5 or higher:

https://www.arduino.cc/

Install Céu:

https://github.com/ceu-lang/ceu/

Clone Céu-Arduino:

$ git clone https://github.com/ceu-lang/ceu-arduino
$ cd ceu-arduino/
$ git checkout v0.40

Configure:

Edit the Makefile.conf to set your configurations and preferences:

$ gedit Makefile.conf

Clone the Libraries:

$ cd libraries/
$ make clone

Each library provides documentation in separate:

https://github.com/ceu-arduino/

Use

Run make with the file you want to compile & upload:

$ make CEU_SRC=examples/blink-01.ceu

This example blinks the on-board LED every second.

Certify that your Arduino is connected to the USB.

Examples

The examples/ directory contains a number of examples.

Blinking a LED

The example blink-01.ceu assumes that a LED is connected to pin 13.

The program is an infinite loop that intercalates between turning the LED on and off in intervals of 1 second:

#include "out.ceu"              // uses GPIO (OUT_13)
#include "wclock.ceu"           // uses timers (await 1s)

output high/low OUT_13;         // declares OUT_13 an output pin

loop do                         // runs an infinite loop that
    emit OUT_13(high);          //   - turns the LED on
    await 1s;                   //   - awaits 1 second
    emit OUT_13(low);           //   - turns the LED off
    await 1s;                   //   - awaits another 1 second
end                             //   - repeats

Switching a LED

The example button-01.ceu requires a simple circuit with a switch button connected to pin 2.

The program waits for changes on pin 2 (the switch), copying its value to pin 13 (the LED):

#include "out.ceu"
#include "int0.ceu"                 // declares input `INT0` (UNO=D2, MEGA=D21)

output high/low OUT_13;

var high/low v = call INT0_Get();   // gets current value of the pin
emit OUT_13(v);                     // sets the LED to this value

loop do
    await INT0;                     // waits for a pin change event
    v = call INT0_Get();            // gets the new state of the pin
    emit OUT_13(v);                 // sets the LED to this value
end

Blinking in Parallel

The example blink-02.ceu requires two additional LEDs connected to pins 11 and 12.

The program blinks the LEDs with different frequencies, in parallel:

#include "out.ceu"
#include "wclock.ceu"

output high/low OUT_11;
output high/low OUT_12;
output high/low OUT_13;

par do
    loop do
        emit OUT_11(high);
        await 1s;
        emit OUT_11(low);
        await 1s;
    end
with
    loop do
        emit OUT_12(high);
        await 500ms;
        emit OUT_12(low);
        await 500ms;
    end
with
    loop do
        emit OUT_13(high);
        await 250ms;
        emit OUT_13(low);
        await 250ms;
    end
end

Fading a LED

The example pwm-01.ceu assumes that an LED is connected to pin 06.

The program fades the LED from 0 to 255 and from 255 to 0 in two consecutive loops:

#include "pwm.ceu"
#include "wclock.ceu"

loop do
    var int i;
    loop i in [0->255] do
        spawn Pwm(6, i);
        await 5ms;
    end
    loop i in [0<-255] do
        spawn Pwm(6, i);
        await 5ms;
    end
end

Serial Echo

The example usart-01.ceu reads and write strings from and to the serial in a continuous loop:

#include "usart.ceu"

spawn USART_Init(9600);

loop do
    var[20] byte str = [];
    await USART_Rx(&str, _);
    await USART_Tx(&str);
end