Re: C-64 joystick port, pin 7

From: David Wood (jbevren_at_starbase.globalpc.net)
Date: 2003-06-17 16:41:03

But you CAN draw so much that the system becomes mysteriously unstable ;-)
Bear in mind also that the 5v regulator is behind a fuse inside your brick
psu that blows before the current limit on the 5v regulator is reached.

-David

On Tue, 17 Jun 2003 wlevak@cyberspace.org wrote:

> 
> The +5 volts comes from a 7805 voltage regulator, which has built in
> current limmiting.  You can't overdraw it.
> 
> 
> 
> 
> On Mon, 16 Jun 2003 Gianmario.Scotti@nokia.com wrote:
> 
> > Hello!
> > 
> > 
> > I got hold, through a purchase of some old junk, of an Amstrad joystick. I boldly proceeded to try it out on my C-64, but noticed something is not quite right. Note that the C-64 didn't reset.
> > 
> > So then I went to check out the Amstrad joystick port pinning, and found out that it uses pin 7 for the Fire 1 button. This deviation from the Atari "standard" is rather alarming, since on the C-64 pin 7 is connected to +5 Vcc. Further analysis of my Commodore showed that the joystick port is still intact and functional. 
> > 
> > How can this be? According to the  C-64 schematic (this part of the schematic should be common to all revisions) http://www.funet.fi/pub/cbm/schematics/computers/c64/250469-rev.A-left.gif pin 7 goes directly to the system's +5 Vcc. So when I pressed the Fire 1 button, I should have fried one of the fuses, or at least reset the system - which didn't happen.
> > 
> > 
> > thanks in advance
> > 
> > 
> > 
> > mario
> > 
> > 
> > 
> >        Message was sent through the cbm-hackers mailing list
> > 
> 
> 
>        Message was sent through the cbm-hackers mailing list
> 


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