[Coco] ADOS-3 (was: 26-3029 floppy disk controller.

[Arthur Flexser]

On Tue, 17 Jan 2006, Roger Merchberger wrote:

> Art,
> 
> What is the availability of Extended ADOS-3 & how much does it cost?
> 
> It's one of those things I'd always wanted back when I had no money and now 
> that I'm [1] getting back into the CoCo (looking for a desk for the CoCo3 & 
> CM8 right now...) it's something I'd really be interested in.
> 
> I have an EPROM burner & (I hope) a controller that can handle a 16K 
> image... altho one Disto Mini-Controller I have won't boot at all with a 
> ROM installed... odd. :-/
> 
> To the list:  Will an FD502 take a 16K ROM? IIRC, it was the only RS 
> controller that could take a 27c64 28-pin chip, but I don't know what it 
> would take to get a 27c128 shoehorned into one...

I no longer sell Extended ADOS-3 (or ADOS-3, which is required by Ext. ADOS-3),
having disposed of all my CoCo stuff when I moved from Florida to New Jersey
last summer.  Feel free to pirate a copy from anyone who will give you one.

The FD502, as I recall, will take a 27128 if you run a wire between the pin
corresponding to the highest address line of the chip over to the corresponding
pin of the edge connector.  Tandy for some reason grounded this pin of the chip,
so you also have to cut the trace connecting the pin to ground.  Instructions
are given in the Ext. ADOS-3 docs, which I don't have a copy of handy.  (This
modification doesn't affect the controller's compatibility with 8K ROMs.)  The
FD502 is thus the easiest Tandy controller, by far, to use with Extended ADOS-3,
though third-party controllers are better still, requiring no modification.

Art