[Coco] Re: CoCo needs?

[Roger Merchberger]

Rumor has it that jdaggett at gate.net may have mentioned these words:
>Roger
>
>According to the data sheet.

Datasheets are good... ;-)

Also, I'll "assume" that your dyslexia is getting the better of you, and 
you're transposing the central 9's and 7's of the partnumbers, maybe? (I'm 
that way too, it took me 3 reads through to notice that they didn't seem 
right... ;-)

>Pin #25 on the 2971/3 will activate an internal divide by 2 of the clock 
>if the clock is
>2MHz. On the 2975/7 this is side select output.

OK, but how does this compare to the 1773? That's the 40-pin chip used in 
the newer (5V only; FD50[012] controllers and the Distos...) FD controllers.

Also, the gray matter is kinda fuzzy here -- but IIRC the standard CoCo 
controllers could handle a maximum of 4 drives, *if SS*. Didn't OS-9 
"sacrifice" DS3 to enable double-sided functionality, thereby allowing a 
maximum of 3 DS drives? (Please correct me if I'm wrong - as I said, it's 
been a *long* time for some of this! ;-)

So, that said, do we _need_ the side-select as is, or is it better to have 
the /2 line?

[[ If those datasheets are of made of electrons, I certainly wouldn't mind 
a copy... ;-) ]]

>Also the spec states that the 1973 and the 2973 are software compatible.

Hrm, so that sounds a bit promising for the 1773 as well...

>where can one get 2973?  How much? Dip or PLCC?

I'll only tell you if you don't hog 'em all! :-)

Just Kidding. $7 each at www.bgmicro.com. Not sure *how many* in stock, but 
they have several different floppy controller chips listed.

I do know that after *years* (read: almost a decade!) of searching, I 
finally found one "chipmonger" that had a few 1773's in stock... Don't know 
if there was a minimum order, tho. I'll have to look up that email...

I'd guess that said "chipmonger" could quite probably acquire 2793's pretty 
easily if he had 1773's in stock... so there might be hope yet!
;-)

Laterz,
Roger "Merch" Merchberger

--
Roger "Merch" Merchberger   | "Profile, don't speculate."
SysAdmin, Iceberg Computers |     Daniel J. Bernstein
zmerch at 30below.com          |