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Switchless JiffyDOS kernal switcher?

Posted: Mon Apr 08, 2024 3:25 pm
by 8bitDenial
My C64 was bought from the same seller as my recent Vic-20 purchase.

However, the 64 came fitted with a switch-less kernal switcher which starts the C64 in JiffyDOS, but changes to the standard kernal if powered on with the Restore key held down.

I purchased the Vic-20 JiffyDOS kernal overlay images and would like to add JiffyDOS, making it behave in the same way as the C64 (i.e. JiffyDOS kernal by default, hold down the Restore key on power-on to get the standard Vic-20 kernal).

Would the same switcher as fitted into my C64 work in the Vic (assuming I burn the correct ROM) and if so, where could I buy a switch-less kit to place an EPROM into?

Re: Switchless JiffyDOS kernal switcher?

Posted: Tue Apr 09, 2024 12:00 am
by srowe
The RESTORE key handling in the C64 is quite different to the VIC, it goes through a 7474 flip-flop if I recall. Do you have a photo of how this is wired up in the C64?

Re: Switchless JiffyDOS kernal switcher?

Posted: Wed Apr 10, 2024 7:20 pm
by 8bitDenial
Thank you.

I'll check and upload a photo.

Re: Switchless JiffyDOS kernal switcher?

Posted: Sat Apr 13, 2024 9:48 am
by srowe
If it's this device

https://github.com/bwack/C64-Switchless ... 56-adapter

Then it uses the EXROM signal from the PLA. There's no equivalent of that on the VIC-20.

Re: Switchless JiffyDOS kernal switcher?

Posted: Fri Apr 19, 2024 7:58 am
by MCes

Re: Switchless JiffyDOS kernal switcher?

Posted: Tue May 07, 2024 9:25 am
by 8bitDenial
Having received my PAL JiffyDOS ROM from retrorewind and finding I needed to fit a turned-pin socket, I went the whole 9 yards and re-capped my Vic-20, while I had the soldering iron out.

Video quality improved slightly and JiffyDOS works a treat. When paired with an SD2IEC, it loads games blazingly fast.

However, I’m now left with an aesthetic challenge.

Where to mount the toggle switch?

Where would be the best place to mount it, which wouldn’t spoil the original look of the Vic?

Realising It doesn’t NEED to be a toggle; Has anyone come up with stylish alternatives?

Re: Switchless JiffyDOS kernal switcher?

Posted: Tue May 07, 2024 5:31 pm
by Orangeman96
8bitDenial wrote: Tue May 07, 2024 9:25 am Where would be the best place to mount it, which wouldn’t spoil the original look of the Vic?
Congrats on upgrading to JiffyDOS, 8bitDenial!

If it were me, I would leave the case intact, route the wires out a preexisting opening, and mount the switch as if it were an external peripheral (but I am a bit of a preservationist when it comes to vintage hardware).

OGM