Terra customization: Arduino Mega Basic customization

In this page we present a customization, called TerraIno, that is a very light customization for Arduino Mega Board using only simple radio communications and GPIO.

TerraIno - Basic Operations

This Terra customization mainly provides only very basic "send" and "receive" events, GPIO operations, and a specific DHT11 Temperature/Humidity Sensor interface. Table 1 presents the current TerraIno events interface and Table 2 presents the functions interface.

Some code examples are presented at the end.

The local operations comprises operations to access input and output devices of the microcontroller. Terra encapsulates all these operations in a component called Local Operations providing them as input and/or output events. Timers, on the other hand, are handled directly by the Céu-T language with the await time command.

The SEND() command is a basic send command where only the nodes in the radio range may receive the message. If the field target is set to BROADCAST value, all nodes in the range will receive the message. On the other hand, if this field is set to a specific node identifier, only this node will receive the message (if the node is in the radio range). A SEND_DONE() event indicates that the send request was processed by the radio. The RECEIVE event returns a received message. A variation of the SEND() command is the SEND_ACK() command that requests an acknowledgement from the target mote. In this variation the SEND_DONE_ACK() event return a boolean value indicating the acknowledgement. Additionally, TerraIno implements a simple message queue to support message buffering needs.

The user must define the radio message data structure before create a message variable.

Events definitions

Available functions

Constant definitions

Code samples

Digital Pin - Blinking the board Led - D13/PortB.7

#include "TerraIno.defs"
pinMode(PORTB,7,OUTPUT);  // also may use: pinMode(D13,OUTPUT);
loop do
    await 500ms;          // Waits 0,5 seconds
    pinToggle(D13);       // Toggle LED value
end

DHT11 Sensor - Counting temperature value

Connect the DHT data pin to D21/PortD0/Int0.

#include "TerraIno.defs"
pinMode(PORTB,7,OUTPUT);    // also may use: pinMode(D13,OUTPUT);
var dhtData_t data;         // Data variable to store result
var ubyte count;            // Blink LED counter
loop do
    emit REQ_DHT(INT0);     // Request a DHT11 read
    data = await DHT();     // Waits the data
    count=data.temp;        // Count the Temperature or the Error code
    if data.stat != 0 then count=data.stat; end
    loop i, count do        // Loop to blink the LED
        pinWrite(D13,HIGH);
        await 150ms;
        pinWrite(D13,LOW);
        await 150ms;
    end
    await 500ms;
end

Interrupt Pin - Trigger a pin interruption

Connect a push button to GND and D20. The LED will toggle once when you press the button. Do nothing when releasing it.

#include "TerraIno.defs"
pinMode(PORTB,7,OUTPUT);    // also may use: pinMode(D13,OUTPUT);
pinMode(D20,INPUT_PULLUP);  // Int1 pin as input
intConfig(INT1,INT_FALLING);// Interrupt from 1 to 0.
intEnable(INT1);            // Enable the interrupt
intClear(INT1);             // Clear, if necessary, the interrupt flag.
loop do
    await INT_FIRED(INT1);  // Waits for an interrupt Int1
    intClear(INT1);         // Clear the IntFlag
    pinToggle(D13);         // Toggle the LED status
    await 30ms;  			// Debouncing: Waits some time before next Int1.
end