xAP to C-Bus Gateway Update

Submission by Kevin Hawkins – OK – another update. This is of the Rabbit development system with the following piggyback boards installed – a Rabbit 3200 core attached lower left corner, plus the C Bus SIM upper centre (blue board) and a 4 line graphic lcd display with keypad and LED’s.

The power supply connector is upper right corner and the blue Ethernet cable emerges centre left. The two wires (white and blue) are the C-Bus connection. For those interested the power supply components are top right on the main pcb and the space at the top left is for a secondary Rabbit ‘slave’ processor. Two DB9 connectors on the right hand side offer extra RS232 serial ports.

A very productive week really – I have totally re-coded the web server and the ftp server – I had borrowed some code earlier and I think in later versions of Dynamic C (v8) more extensive libraries now allow me to implement these in a much neater fashion. However I learned an awful lot from the previous code both about how web servers actually work, how to implement pages with dynamic content and about C itself so it was well worth it. So we now have a web server with dynamic pages for C-Bus content, and an ftp server with both anonymous (read only) access and an administrator who can create pages for the web server to use. I am just now looking into the best way to allow people to include their own dynamic content. I have the C based cgi routines working too. The C-Bus side has been running reliably now for some time and only balks at a few of the more complex message streams (ignored). I have still to incorporate some group naming into both the web displays and the xAP messages, this means reverse engineering the C-Bus project files format or manual entry

I have also made progress on my hardware solution. I have got ten boards made up as a partial hand build so no fancy silkscreens/solder masks, plus there will be a couple of link wires on the board. Photos soon when I receive the boards. These look nothing like the photo btw, they are much simpler in design incorporating power supply, Rabbit mounting sockets , extra I/O headers, serial port level converters and C-Bus SIM mounting.

These units will simply offer a C-Bus interface (via a SIM) and a spare RS232 port. I will use this port as a serial to Ethernet xAP bridge (probably not in initial software release ). Actually there is another spare serial port that can either be connected to a C-Bus RS232 computer interface obviating the need for the C-Bus SIM – or in my case I will be using this for a connection to the Galaxy Alarm panel. As few of you need this I >MAY< look at other options, for example connection to a Meteor Caller ID unit or an X10 interface or to provide a basic control protocol (non xAP) for connection to say HomeVision or ACE. We’ll see. This would all be extra functionality, possibly chargeable.

Later on I may have a more capable board with other interfaces but I’ll see how these go first.

So… it looks like I may need some early adopters soon – the board uses a Rabbit 2200 core and needs a SIM too unless you connect directly to your C-Bus PC interface. The cost of the board, including the software will be approx £50 to UKHA’ers. In addition you need a Rabbit core with Ethernet interface at around £45 (2200 – 256/128K)or £65 (2250-512/512K) depending on what size RAM you choose – I stongly recommend the latter. You need also either a C-Bus RS232 interface which you probably have already or a C-Bus SIM which will add another £50. So if you are interested in reserving a board email me now. If I get a very low level of interest I shall probably not make any more. Please note the board is not in any way cased or CE approved and does not come with a power supply either – you need to provide a small wall wart that provides 9-12V DC – I can supply these too if you like. I should have boards available in around 3 weeks or so. I have assumed the sale of 10 units to get a small price break on the cores.

BTW – early on in the products life there are inevitably going to be bugs. You can’t upload new firmware to these units from a PCvia a serial port – either the units will have to come back to me or you will have to buy a programming cable from the UK distributor which costs around £25. If you do the latter I will be posting updates on my website for new features / bug fixes.

Please note that I am making no profit on these early boards and I am not charging for the software either. Accordingly nor am I promising to continue to develop the product either, however I will ensure that the current C-Bus feature set works as it should. Extra features may be chargeable later but it will always be a low cost upgrade. Later on in a commercial release when the product is more mature the C-Bus option may well be chargeable as a software option for the board.

Hope that makes sense I am trying to be as fair as possible, months of work has gone into this from my side and although I don’t want in any way to profit from the UKHA members for this (I did it for my own need) I am not going to expose myself to a loss on building and selling hardware either. You can buy the Rabbit (and programming lead) from the UK distributor and the C-Bus SIM from Clipsal if you prefer, and just the board and software from me at £50.

Cheers Kevin

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1 Comment on "xAP to C-Bus Gateway Update"

  1. HI Kevin
    Just want to know if you have C Bus protocol as i have requirement where i have to send C Bus information from Serial port to make some light on/ OFF. I am planing to use C Bus PC interface.. but do u know electricial details of C Bus protocol ?


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