[Coco] Dual UART with FIFO Card for the CoCo

[Gene Heskett]

On Sunday 13 June 2010, sales at gimechip.com wrote:
>On CoCo3.com, I asked for project ideas and requests. One request was for
> a Dual UART card w/FIFO. I thought this would be a good one, so I spent
> yesterday studying the datasheets and then, this morning I created a
> preliminary design using E.A.G.L.E. The complete project is now posted
> here:
> http://www.coco3.com/community/2010/06/a-dual-uart-with-fifo-card-for-the
>-coco Let me know if you spot any potential problems with the design.
>Thanks - John

The only problem I see is the additional i/o addresses it needs.  8 per chip 
sure beats the original 16450's 16 per chip, but with the coco's very 
limited I/o mapping, at least in os9, finding that space is going to be fun.

In my own situation, I do have a dual port ACIA, addressed adjacent to each 
other from FF64 to FF6B (iirc), which meant I had to hack Rogers BT pack to 
use FF60-63.

I would like to ask how much trouble it would be if we could figure out a 
way to isolate the first $40 of page $FF by more fully decoding the two 
PIA's it uses, so they would not see a /cs except at $FF00-03, and $FF20-23.

That would clear out and make usable a considerable amount of i/o address 
space, allowing this to be addressed at $FF10-1F for instance.  That would 
still leave room for 6 more 4 bit wide devices.

So basically, we first need a kit that will fix all of our coco's, freeing 
up this very sorely need i/o space. 

I looked at that myself but about 2 decades ago, so any ideas I may have had 
then are moot now.  And I of course am not the least bit allergic to 
plugging in my iron and fixing it as long as I can adequately see what I'm 
doing.  Diabetes is trying to fix that for me now.  But, I'm still a C.E.T., 
so I'd be willing to be a test site, I have more than 1 coco3 here.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
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