Clipsal C-Bus User's Guide download pdf (Page 11)

CHAPTER 2

Hacking

Information about using the hardware and software.

2.1 Ofﬁcial documentation

Ofﬁcial serial protocol documentation is available from Clipsal’s website:

http://training.clipsal.com/downloads/OpenCBus/OpenCBusProtocolDownloads.html

You should generally implement software in conjunction with reading these guides. This library provides a fairly low

level API for parsing and generating CBus packets, and understanding what is happening on a lower level is needed

when understanding use of this library.

There is a large amount of documentation in there that says “these items are deprecated and shouldn’t be used”. I’ve

noticed a lot that C-Gate and Toolkit will interact with the hardware in these “deprecated” ways...

This doesn’t mean implement the library to talk this way. You should implement it properly. Just be aware than when

working with implementing a fake PCI or parsing out packets that Clipsal’s software generated, be aware they’ll do

strange and undocumented things.

2.1.1 Geoffry Bennett’s reverse engineering notes (2001 - 2004)

Geoffry Bennett gave a talk at a LinuxSA meeting in 2001 and at Linux.conf.au 2004 about his experiences with

reverse engineering C-Bus. At the time there was no ofﬁcial protocol documentation available.

The Linux.conf.au 2004 notes cover a lot more information, includes some information about dumping and reverse

engineering the contents of NVRAM in units, a Perl client library, and an emulator used for older versions of the

Clipsal programming software.

2.2 CNI / network protocol

The C-Bus Toolkit software has a CNI (network) interface mode. This is really just the serial protocol over a TCP

socket. Note that libcbus does not currently implement a CNI client. There’s a further discovery protocol, however

this requires special implementation which has not been done.

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Clipsal C-Bus User's Guide Page 11