I32CTT is a lightweight protocol for control, transport & telemetry for the AT85RF233 and the Teensy.
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Integer 32-bit Control, Transport & Telemetry (I32CTT) Protocol

I32CTT is a state-less protocol developed by the Hackerspace San Salvador to transmit 32-bit messages using packets of data between "nodes".

Each node in I32CTT could take the role of "master" (if the node ask for data) or "slave" (if the node sends data). However, a node could act as both master or slave for other nodes depending on the implementation.

Each node can expose "endpoints", each "endpoint" in a node represents a group of 32-bit records identified by unique addresses. To make the system more human-friendly each endpoint can be identified by three-leter ASCII ID. Each node could implement up to 255 endpoints and 65,536 individual records.

The only underlying condition for the protocol to work is to have a medium wich supports packet messaging. This makes it possible to migrate this protocol for use over UDP or even Point-to-Point links.

How it works?

I32CTT follows a master-slave architecture. And it works making "Queries" and listening for "Replies". However, the protocol is designed to be fully state-less. There is no guarantee of delivery of any message. Implementations should be designed with this characteristic in mind.

The protocol currently supports the following messages:

  • Read(endpoint, address_1 ... address_n): Sent by the master to read records from the specified endpoint.
  • Answer Read(endpoint,(address_1, data_1)...(address_n, data_n)): Response sent by the slave with the data requested for the specified addresses.
  • Write(endpoint,(address_1, data_1)...(address_n, data_n)): Sent by the master to write records on the specified endpoint addresses.
  • Answer Write(endpoint, address_1 ... address_n): Response sent by the slave with the affected records on the node.

The protocol always assumes a point-to-point topology between the nodes, even if the underlying technology allows other topologies. For this reason things like address resolution should be resolved by the underlying "interface".

Supported Hardware

For now I32CTT is only supported on the following hardware:

*Partially supported, requires OpenLabs.co AT86RF233 radios.

Supported underlying interfaces:

  • Null interface (echoes locally)
  • Microchip AT86RF233 (IEEE 802.15.4 radios)
  • UART link


Copyright 2017-2018 Hackerspace San Salvador Contributors: Mario Gómez / Joksan Alvadado

I32CTT is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

I32CTT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with I32CTT. If not, see http://www.gnu.org/licenses/.