[Coco] [Color Computer] coco ethernet project

[jdaggett at gate.net]

On 23 Apr 2009 at 22:15, James Dessart wrote:

> On 4/23/09, stinger30au <stinger30au at yahoo.com.au> wrote:
> > i just stumbled across this on the net
> >
> >  http://skwirl.com/coco/ethernet/
> >
> >  from 5 years ago
> >
> >  surely it must be built by now
> 
> That'd be nice, wouldn't it? A number of factors conspired to keep me
> from even designing the card, and now my CoCo is too far away to even
> bother.
> 
> However, someone with a modest amount of circuit design skills should
> be able to throw together a design using a CS8900a chip, which is the
> one used in most 8-bit ethernet projects. A driver could easily be
> written to work with uIP, possibly using the C64 driver for The Final
> Ethernet as inspiration.
> 


Hardware is not an issue. One can use a derivative of the Olimex board 
that they and Sparkfun sell for about $35. 

> If such a person were ok with the card taking 32 bytes of IO space,
> the implementation could be quite brain-dead. I wasn't okay with that,
> and my circuit design skills aren't at the point where I'd be
> comfortable putting that together on my own.
> 

Using a FPGA in front of the CS8900 chip one can reduce the I/O 
requirements to say four bytes. Some simple state machine or even the 
programable state machine Picoblaze would be a nice interface to the 
CS8900 chip. 

> Then the question arrives, what are you going to do with it? Once you
> have ethernet hardware and a working IP stack, your options are mainly
> limited by RAM.
> 
Ah yes this is the fun part. what applications are there that can use this? 
better yet who is willing to write applications for it. hardware without 
software is somewhat wasted effort. 

james