[Coco] Embedded coco

[jdaggett at gate.net]

Eric

I checked and I stil have my Ivex tools on the hard drive. I have a fairly good 
extensive library for PCB and Schematic entry. I have the 6809/E and 6821 and 
quite a bit of memory symbols. I have some Natinal Semiconductor DACs and 
ADCs also. Address decoding can be done using TTL logic or a PLD/CPLD. 

I can punch out a quick schematic and have it up on my web page by New Years 
Day.  Maybe even a layout depending on how compact and how many parts. 

Mapped the Ram at the bottom of memory $0000 $1FFF and map the ROM from 
$2000 to $FF00 and then from $FFF0 to $FFFF. Leaving $FF00 to $FFEF as I/O.

I already have the 6809,  6116 and 2716 data and address wired on a achematic. 

To get a barebones schematic up now is just add decode logic and oscillator circuit. 


james


On 18 Dec 2003 at 10:47, peak at mail.polarcomm.com wrote:

> James
> Those are good questions!
> As to what kind of ram I was thinking of static ram because 
> that would eliminate refresh. The size of ram would be 
> optional. For a start I probably would use just one 6116 chip 
> which would give 2KB. As to Rom I would start with a 2716 or 
> 2764 with the Intel pinout.
> 
> As to the coco's expansion port my Idea is to put jumper pads 
> on the ckt board so that a person could add a full coco 
> expansion port if desired.
> 
> The main Idea here is to design a board with optional 
> connectors and interfacing so that individuals might 
> customize it depending on their own desires for embedding 
> a "coco type" computer.
> 
> Layout : I only have "PCB123" layout software at this time so 
> that is what I will use but I also plan on publishing just a 
> schematic so if you wanted a different layout you could.
> I will design this thing with lots of options though. The 
> board could have solder pads for surface mount components as 
> well as the older type plated through hole pads for sockets.
> The sizes of ROM/RAM,number of PIA's,Inclusion of a DAC chip,
> and or Cartridge connector will all be optional.
> 
> I hope this answers your questions and I am open to 
> suggestions. If there is enough interest in a mini-coco then 
> perhaps we could make it a community project and convince 
> cloud 9 or someone to produce a kit. It could be made 
> available as just a bare ckt board or a ckt board with 
> connectors etc.
> 
> Thanks for your input!
> Eric the Technician.
> 
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