RoveComm

The UDP and TCP packet protocol used by MRDT modular microcontrollers

Cloning / Updating

Since the manifest.json is located in a different repository the steps for cloning and updating the repository are a bit different than usual. Everytime the manifest.json is updated, the update command listed below needs to be executed.

• Clone: git clone --recurse-submodules https://gitlab.com/MissouriMRDT/RoveComm_Arduino.git
• Update: git submodule update --init --recursive

Dependencies

The current implementation of RoveComm supports Tiva C and Teensy 4.1 Microcontrollers. The ethernet libraries used are Energia Ethernet for the Tiva C and NativeEthernet for the Teensy 4.1.

Packet Structure

A RoveComm packet header is 6 bytes long:

Field	Size	Description
version	uint8_t	The version of RoveComm this packet was sent from (always 3)
dataId	uint16_t	A number indicating the purpose of this packet
dataCount	uint16_t	How many elements in this packet's data array
dataType	uint8_t	An enum representing the type of the packet's data

The packet then countains a dataCount number of data elements. The size of each element depends on the dataType.

Due to memory limitations, the Tiva can only support 21,845 uint8_ts, 10,922 uint16_ts, 5461 uint32_ts, 5461 floats, or 2730 doubles at once.

Due to memory limitations, the Teensy can only support 32,767 uint8_ts, 16,383 uint16_ts, 8,191 uint32_ts, 8,191 floats, or 4,095 doubles at once.

Use

First, include RoveComm.h and create an instance of the RoveCommEthernet class:

#include <RoveComm.h>
RoveCommEthernet RoveComm;

Before using RoveComm, you must call RoveComm.begin() with the IP address of the board:

void setup() {
    // all known ip addresses are already defined in RoveCommManifest.h
    RoveComm.begin(RC_BOARDNAME_IPADDRERSS);
}

To read any incoming data, use RoveComm.read():

RoveCommPacket packet;
void loop() {
    bool packetWasRead = RoveComm.read(packet);
    if (packetWasRead) {
        // do something with the data
    }
}

It is a common pattern to switch over the dataId:

RoveCommPacket packet;
void loop() {
    RoveComm.read(packet);
    switch (packet.dataId) {
    case RC_BOARDNAME_ACTION1_DATAID:
        peformAction1();
    case RC_BOARDNAME_ACTION2_DATAID:
        peformAction2();
    case RC_BOARDNAME_ACTION3_DATAID:
        peformAction3();
    }
}

Methods for sending data:

Method	Description
RoveComm.write(dataId, dataCount, data);	Send data over UDP to all subscribers
RoveComm.write(dataId, datum);	Send a single datum over UDP to all subscribers
RoveComm.writeTo(dataId, dataCount, data, IPAddress, port);	Send over UDP to the given IP/port
RoveComm.writeTo(dataId, datum, IPAddress, port);	Send a single datum over UDP to the given IP/port
RoveComm.writeReliable(dataId, dataCount, data);	Send data over TCP to all open connections
RoveComm.writeReliable(dataId, datum);	Send a single datum over TCP to all open connections

Examples of how to implement RoveComm on the Tiva C Microcontroller and Teensy 4.1 are here.

Planned Features

• WiFi compatibility (ESP32 boards only)
• Send data to IP/port over TCP with writeReliableTo()