Projects Resume
Fork me on GitHub

LightBus library (I2C)

Introduction

LightBus is a Serial UART communication protocol made for student robot. The purpose of this protocol is to be lighter than others. It sends 2 bytes with Hardware parity (19 bits). At 57600 baudrate, it took 0.3ms to send a function and a data.

The code is split in 2 parts. One for the master and one for the slaves. This ensure to have a lighter code and more space for our usefull code.

PROS & CONS

####PROS

  • Light (2 bytes, over only ONE wire)
  • Cheap (No need for any shield)
  • Easy (Use the common Arduino RX-TX)
  • Hardware
  • Hardware parity check
  • No crypt, we can plug in & debug (Bluetooth RX/TX module is perfect)
  • Opensource
  • I2C is open to use it with Servos (dynamixel)

####CONS

  • Only ONE master (avoid collisions)
  • Only 8 [0:1:7] slaves devices
  • Only 16 [0:1:15] functions
  • Have to unplug RX/TX before sending the sketch
  • NO CRC check (Would take one/two bytes)
  • NOT a differential pair (would need a shield)
  • NO crypt, we can plug in & hack
  • NOT universal
  • NO Aknowlegde / Answers (Possible improvement)

CONNEXIONS

To connect arduinos, you can just connect the TX of the master to every slave’s RX. The TX of slaves is unused in this version of LightBus.

MASTER TX <=> RX SLAVE

PROTOCOL

  • X = adress
  • Y = function
  • D = data

BYTE 1 : 1XXXYYYY

BYTE 2 : 0DDDDDDD

1 adr(3) func(4) 0 data(7)

Improvement

If you want to improve the code, clone it, branch it and contact me : alexis.paques@gmail.com

LICENSE

This program 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.

This program 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 this program. If not, see http://www.gnu.org/licenses/.

Credits

Alexis Paques