FOR SALE: "wireless" JiffyDOS for VIC20 (PAL/NTSC)

[MCes]

The first JiffyDOS switching method was a simple mechanical switch that had to be installed making a hole on the case,
but people wasn't happy to hole own VIC20...
A "switchless" solution was developed, it sense the pressure on an original key during the boot-up for choosing between original/jiffy Kernal,
the "switchless" solution imply to connect a pair of wires on motherboards (soldering them or hooking them),
it's better than mechanical solution, but not all can/want to solder wires on motherboard....

Now I'm proposing a "wireless" solution:
it will be sufficient to plug it on kernal socket and it will work without piercing the case and WITHOUT EXTRA WIRES!
It's present also a jumper to choose the system standard: PAL or NTSC.

How to handle switching between kernals?
The VIC20 will boot-up with standard kernal (I prefer always that on standard boot-up the machine seem not modified....)
and for swapping the kernal a RESET has to be performed, Hardware or Software!

Hardware: lowering the /RES line (example: pressing the RESET button on an external card...)
Software: typing "SYS64802"(+"RETURN").

It's easy, it's simple.....

19€ (8$ royalty fees included) + eventual Paypal fees + shipping cost

[brain]

Intrigued. How does it work? I assume it looks for read from reset vector location, but could be wrong...

[MCes]

Intrigued. How does it work? I assume it looks for read from reset vector location, but could be wrong...

your intuition is right: this is the starting point of this little project that can only to use the kernal ROM chip signals to smell the bus activities and the machine states....

On "READY 64" forum I posted on April 2014 the schematic of a my realization that I never seen before: the switchless solution (it was for 4 kernals), I never search deeply, but I never found a similar idea precedentely posted....

I think that also this new project is original, especially because it doesn't imply any microcontroller activity to (decide to) swap the Kernals images...

[Noizer]

Hi MCes, offer sounds interesting. Can you kindly explain how the chip installation have to work properly?
So if I understood right 2 times reset works as normal reset, but what is with short reset E378?
BR

[MCes]

When the VIC 20 is powered on it starts with the normal kernel.

For swapping between the 2 kernals the Reset routine has to be executed, it can be done or lowering the /RESET line or typing "SYS64802"+RETURN.
The reset routine will be executed each time that it is called.
The kernal will swap each time that the reset routine is called.

The complete reset procedure is also useful because the 2 kernals initialize the machine in a little bit different manner.
The $3E78 call (BASIC Cold Start) won't swap the kernals.

[groepaz]

why not AND the state of the restore key to the input of your circuit.... then it would swap only when holding restore when resetting (which may be more practical)

[orion70]

Please, for the following technical discussion go here.

This is a buy and sell thread.