[Coco] Any news on the so called CoCo4 or NextCoCo projectthatBjork was heading?

jdaggett at gate.net jdaggett at gate.net
Wed Nov 17 10:47:26 EST 2010

I maybe weighing on this a bit late due to to many other commitments and irons in the fire. 

>From a hardware engineer's point of view I see a COCO4 or what ever it is to be called

1) FPGA route is pretty much the modern way to go. Saying that there probably is no one 
board out there that is 100% everything needed to do a COCO4.

2) Software emmulation still requires a board of some type. Whether PC base or FPGA 
based. Either case the cost will be upwards to $400+. 

3) A dedicated FPGA board just for our needs may sound real nice but also has it flaws. One 
is price. A second is a potential to lock into a design that may not be as flexible in the near 
future. Therefore, bocomes to costly to upgrade or modify.

So what to do?

One suggestion that I would throw out that has already been suggested. Instead of one board 
do all have several boards that plug into a main board. I would entertain a suggestion that 
there be a main board about the size of the Arduino Mega (2.1 inch by 3.9 inch). The one 
constant that proliferates any design is the CPU, (John Kent's CPU09). This can sit in one 
small FPGA with enough IO to interface to other boards. A GIME chip stripped of the video 
section takes up 50 slices of a XC3S250E, 85 FFs and 81 4-LUTs. That is coded but 
untested. It can somewhat be ported to Alterra if needed.  

John Kent's CPU09 utlizes 53% of the slices of a XC3S250E, 51% of the 4-LUTs and 4% of 
the Fs. That leaves plenty of room for the GIME chip and some other circuitry. To split 
functionality up into two or more FPGAs is not all that more in cost of silicon. The major cost 
adders will be PC Boards and how many. I just processed a set of five boards through Batch 
PCB for another project I am doing and the quality is as good as any I have seen in my past 
jobs. Cost is reasonable, about $2.50 per square inch in single quantity two layer with solder 
mask and top silk screen. All holes are plated. The five boards totalled ~26square inches and 
cost me far less than $100 shipped. Process time is slow, 15 to 20 business days. There is 
also a means of distribution of any board(s) design through their market place.  

Again I like the idea of the Arduino style with adaptor boards or shields or wings or what ever 
you wish to call them. A design can be some what compact and a design that is as flexible or 
more flexible that some development boards. 

just my thoughts.   

On 20 Oct 2010 at 21:31, Paul Fitch wrote:

> I think the FPGA route is the only realistic method available to do this
> in hardware.  I'm just not that interested in a hardware project.  Doing
> it in emulation (the Coco4) however, has had me wishing very hard that I
> could program at that level.  I just don't see spending hundreds of
> dollars on duplicating hardware that in most any matchup would be inferior
> to the stuff found on every bargin basement Windows 7 starter computer
> available today for under $400.00.  And that's just the brand new stuff.

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