[Coco] Question about the PIA RAM Size input

[wdg3rd at comcast.net]

Oh, you spoiled my punch line.  I was just going to say "fry it and see".

Yes, I can be a basty nastard when I drink, especially when I  remember I have to go back to the dead end in the morning.  Poorly paid as I was, tech support for Radio Shack 25 years ago was a lot more fun.
-- 
Ward Griffiths    wdg3rd at comcast.net

The reason folks don't think of installing Windows as a painful experience is roughly the same reason men don't think of childbirth as a painful experience.      Mike, http://www.theregister.co.uk/2007/03/30/letters_3003/

 -------------- Original message ----------------------
From: coco at yourdvd.net
> actually, depending on the coco (1 or 2) you have and the installed
> memory, depends on how it is jumpered, whether it be to gnd, vcc, pb6
> of the keyboard pia, etc. I wouldn't do it - say it is jumpered to gnd,
> and you output a logic 1 to it - or vice versa - probably wouldn't be
> good. Look over some schematics of various coco models - the jumpering
> scheme is different on the three coco 1 and 2 model schematics I just
> glanced at...r
> 
> > -------- Original Message --------
> > Subject: [Coco] Question about the PIA RAM Size input
> > From: "Darren A." <darccml at hotmail.com>
> > Date: Mon, April 30, 2007 8:27 am
> > To: coco at maltedmedia.com
> > 
> > Hi all,
> > 
> > Does anyone know if any harm can be done by reprogramming the Data
> > Direction 
> > Register of PIA 2 such that the RAM Size input becomes an output?  Since 
> > this line is often jumpered to either GND or +5V, what happens when
> > the PIA 
> > is trying to drive the line?
> > 
> > The RAM Size input is on the 'B' side of the PIA, and the 6821 datasheet 
> > says:
> > 
> > "As outputs, these lines are compatible with standard TTL and may also
> > be 
> > used as a source of at least one milliampere to directly drive the
> > base of a 
> > transistor switch."
> > 
> > Darren
> > 
> > _________________________________________________________________
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