[net.micro.cbm] c64 reset switch

cng@burdvax.UUCP (02/28/84)

<>

Does anyone have a method for connecting a reset switch to the C64?  I've
become pretty frustrated with having to turn the thing off every time it
visits the Twilight Zone.

Homebrew and/or commercial kit would be acceptable.

Tom Albrecht
-- 
	Burroughs Corp.		...{presby|psuvax|sdcrdcf|bpa}!burdvax!cng
	P.O. Box 235		(215) 269-1100
	Downingtown, PA  19335

porter@inuxd.UUCP (J Porter) (02/29/84)

There is a reset line on the serial bus and on the user port
if I am not mistaken.  Simply connect a normally open momentary
push button switch to ground.

Jeff Porter  (inuxd!porter)

miller@uiucdcs.UUCP (miller ) (03/02/84)

#R:burdvax:-152300:uiucdcs:36100057:000:518
uiucdcs!miller    Mar  1 16:40:00 1984

If you want to get fancy, rather than simply connecting reset to ground as Jeff
suggested, you can connect your switch to a one shot.  You can look in the back
of the Programmer's Reference Guide for where/how to add this as they have the
diagrams back there.

A little known side note: the restore key *alone* causes a nonmaskable
interrupt on your c64.  No, not run/stop and restore - just restore alone.
Once the NMI has occured, the software checks to see if the run/stop key is
down.

A. Ray Miller
Univ Illinois

daemon@decwrl.UUCP (03/02/84)

From: pogo::lawrence
Pin #3 on the user port is reset.  Connect a momentary contact switch
from this pin to ground to reset the Commodore.

				Jim Lawrence
				Colo Springs

cuda@ihuxf.UUCP (Mike Nelson) (10/17/84)

I remember reading about a reset switch in one of the various c64
magazines earlier this year.  It was in response to an article which
mentioned shorting pins 1 and 3 of the I/O connector to cause a cold
restart by grounding the reset line.  This particular reset switch had a
diode, a couple resistors, and a cap or two.  The guy that sent it in
said that just shorting the reset line to ground could damage the 
computer.  Questions:

1) Has anyone had trouble with just shorting these two pins?  (outside
of shorting the wrong two together.)

2) Does anyone know what I am talking about?  (Do I?)

I think I've found the article the guy responded to.  It is in the Dec.
or Jan. Compute's Gazette in the Horizon 64 ( or 64 Horizon ) section.
I've looked through all of my other CGs and can't find the schematic
of the suped-up switch.  Thanks.

Happy Hunting
			    Mike Nelson
			    AT&T Bell Labs
			    ihuxf!cuda

miller@uiucdcsb.UUCP (10/19/84)

My c64 has a one-shot which drops the RESET line low.  This provides a warm
start so that you can recover from a fatal crash without turning your machine
off & thus losing what's in memory.  I've known others, however, who simply
shorted the RESET line to ground (active low as I recall).  They haven't had
any problems, but I wouldn't hold the switch down too long if I had that
configuration on my machine.  The back of your PRG will have a circuit which
you can modify if you want to do this.  Their junk is for power up, but can be
changed a bit.  Just trace the RESET line back out & notice where it triggers
it.

A. Ray Miller
Univ Illinois