12 replies to this topic

[Tschibo00]

Hi guys,
after completing the super video, basic switch and SIO2PC upgrade I now installed a hard-reset button (found the schematics on the net) to my 130XE. Here are the schematics:



But you already guessed it: It doesn't work :-(
The thing consists of a mono-flop (74LS123) which simply pulls up pin 8 of the MMU for about 2 seconds. Simultaneously the normal reset button is triggered.
As far as I understand it, the mono-flop shall ensure, that the memory is cleared. Is pin 8 of the MMU the right pin for this?
Or is it just a problem with that pesky 74LS123 which gives only about 3,4V, which shall be something like a High

I also played around with the RC values, resulting in almost anything from a total hang to a soft-reset.

Could you please help me?
Thank you!
Hopper/SquoQuo
aka
Christoph

Edited by Tschibo00, Mon Mar 27, 2006 12:01 PM.

[MEtalGuy66]

Tschibo00, on Mon Mar 27, 2006 11:58 AM, said:

Hi guys,
after completing the super video, basic switch and SIO2PC upgrade I now installed a hard-reset button (found the schematics on the net) to my 130XE. Here are the schematics:



But you already guessed it: It doesn't work :-(
The thing consists of a mono-flop (74LS123) which simply pulls up pin 8 of the MMU for about 2 seconds. Simultaneously the normal reset button is triggered.
As far as I understand it, the mono-flop shall ensure, that the memory is cleared. Is pin 8 of the MMU the right pin for this?
Or is it just a problem with that pesky 74LS123 which gives only about 3,4V, which shall be something like a High

I also played around with the RC values, resulting in almost anything from a total hang to a soft-reset.

Could you please help me?
Thank you!
Hopper/SquoQuo
aka
Christoph

Hmm. never heard of that mod. Ive done Bob Woolley's Frezer reset button many times. It uses a 74xx86 (XOR) to toggle the status of the cartridge present register. It causes a cold reset WITHOUT clearing the contents of your extended RAM. And it does work.

http://atrey.karlin....ri/freezer.html

[classics]

Your mod is trying to trigger the software interlock and crash the OS, then reset.

This will only work if the OS VBI is enabled and running, you have BASIC disabled and no cartridge is inserted.

It could also damage an inserted cartridge, depending on how its wired. I havent actually seen this installed.

You are much better off just installing a normally closed pushbutton inline with the 5v+ power supply.

Steve

Edited by classics, Mon Mar 27, 2006 1:59 PM.

[Bryan]

What about this idea:

A simple OS mod that responds to the actual reset NMI input on Antic (unused in the XL/XE) and performs a coldstart?

-Bry

[classics]

Bryan, on Mon Mar 27, 2006 9:05 PM, said:

What about this idea:

A simple OS mod that responds to the actual reset NMI input on Antic (unused in the XL/XE) and performs a coldstart?

-Bry

True, but if your going to modify the OS you can just add a soft-boot provision, like holding down Select+Reset to cause a coldstart.

Steve

[Bryan]

classics, on Mon Mar 27, 2006 5:32 PM, said:

Bryan, on Mon Mar 27, 2006 9:05 PM, said:

What about this idea:

A simple OS mod that responds to the actual reset NMI input on Antic (unused in the XL/XE) and performs a coldstart?

-Bry

True, but if your going to modify the OS you can just add a soft-boot provision, like holding down Select+Reset to cause a coldstart.

Steve

Well....you're no fun!

[classics]

Bryan, on Mon Mar 27, 2006 11:20 PM, said:

Well....you're no fun!

A hardware only reset would be fun to build. Something with a RAS interrupt that disrupts the first read of the magic ram values after /reset perhaps?

Steve

[Bryan]

classics, on Mon Mar 27, 2006 6:32 PM, said:

A hardware only reset would be fun to build. Something with a RAS interrupt that disrupts the first read of the magic ram values after /reset perhaps?

Steve

You could probably do it with a GAL that latches itself when it "sees" the address check, and clears itself on reset.

-Bry

[Osbo]

I did a simple reset on my space 800XL, I had to connect a wire to one of the chips, to the switch from there to the ground, it worked ok, but I never got to do a complete cold reset...

I found the link

http://www.myatari.c...aug2002/usa.htm

I also been trying to do a switch to enable/disable the BASIC without holding option every time.

Edited by Osbo, Mon Mar 27, 2006 6:22 PM.

[classics]

Bryan, on Tue Mar 28, 2006 12:07 AM, said:

You could probably do it with a GAL that latches itself when it "sees" the address check, and clears itself on reset.

Yep, probably will fit in a 22v10.

Steve

[Bryan]

classics, on Mon Mar 27, 2006 7:53 PM, said:

Bryan, on Tue Mar 28, 2006 12:07 AM, said:

You could probably do it with a GAL that latches itself when it "sees" the address check, and clears itself on reset.

Yep, probably will fit in a 22v10.

Steve

You don't even have to decode the whole address. Just distinguish it from all previous ones.

-Bry

[Rybags]

You can do a hard-reset on a completely un-modded XL.

Just press reset a second time, you have to get the timing just right.

The OS clears all of page 3 during warmstart, which means that the magic numbers at $33D-F get cleared (temporarily).

Pressing RESET again in that small time period will cause a cold-start. Once you get the timing right you can get it to work better than 1 in 10 attempts.

[Tschibo00]

Thanx everybody so far!
What I will try this evening is Rybags suggestion. Because I already have a working mono-flop I could use this to re-trigger the reset button after a given delay.
Maybe this will work fine.
What keeps me from doing the Freezermod-Reset is that I have to unsolder a pin of the GTIA, but if the other idea doesn't work maybe I will try this...