AVR-Chat

Hi Chuck,

> - The data bus is pseudo-CAN.  I use a CAN driver but I'll be doing the
> beginning-of-message bus arbitration by bit-banging (PD2, PD3) and then
> switch to the USART for actual data transfer.  In the future I hope to
switch
> to a AT90CAN128 (built-in CAN support) but I wanted to limit the initial
> hardware/software learning curve so I could get the next version out
faster.

I would strongly suggest you NOT do this. If you have any interest in CAN
then you should use proper CAN hardware.

I hadn't got into the detail of your project until today and now that I see
it is a Model Rail Road project I'm now quite interested. 

What you are suggesting in terms of bit-banging the data bus is what
Digitrax LocoNet does - which works but has limitations. I have done several
LocoNet projects over the years and they are available here:
http://embeddedloconet.sourceforge.net However the last few years of MRR
hobby time have been assisting a team of people to develop a new MRR Layout
Control Bus proposal called OpenLCB http://openlcb.org which in due course
may be adopted by the National Model Railroad Association as NMRAnet.

If you were interested in leveraging the OpenLCB codebase and assist in this
development we would certainly appreciate the assistance.

Regards

Alex Shepherd