Ultimem BLK6
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- polluks
- Vic 20 Amateur
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Re: Ultimem BLK6
No, the VIC-20 (or more precisely the 6502 CPU) itself does not allow for RAM below ROM (like the C64 does). So you can just use the standard memory-areas that are unused in the VIC-20:
RAM1,RAM2,RAM3 ($0400-0fff)
BLK1 ($2000-$3fff)
BLK2 ($4000-$5fff)
BLK3 ($6000-$7fff)
IO2 ($9800-$9bff)
IO3 ($9c00-$9fff)
BLK5 ($a000-$bfff)
Of course the Ultimem can map it's huge memory pretty much any way you like to these areas.
RAM1,RAM2,RAM3 ($0400-0fff)
BLK1 ($2000-$3fff)
BLK2 ($4000-$5fff)
BLK3 ($6000-$7fff)
IO2 ($9800-$9bff)
IO3 ($9c00-$9fff)
BLK5 ($a000-$bfff)
Of course the Ultimem can map it's huge memory pretty much any way you like to these areas.
- Mike
- Herr VC
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Re: Ultimem BLK6
In the C64, the PLA is responsible for the RAM/ROM mapping. That the mapping is (in part) controlled by the I/O port of the 6510 is more of an insignificant detail here.tokra wrote:or more precisely the 6502 CPU
The 'chip set' of the VIC-20 enforces a fixed mapping, how the internal ROMs (BASIC in BLK6 and KERNAL in BLK7) are set. No way to change that with an external cartridge, and - for that matter - there are no /BLK6 and /BLK7 signals present on the cartridge port, anyway.
I have a strong suspicion *why* you are asking this.
If there was any easier way (i.e. without modification on the mainboard and preferably with some external cartridge) to achieve that feat, I'd have people know about this (same applies to my VFLI mod).
Re: Ultimem BLK6
it would be so nice if you could map the e000-ffff block to ram as you can on c64.... but you cant
I'm just a Software Guy who has no Idea how the Hardware works. Don't listen to me.
- Mike
- Herr VC
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Re: Ultimem BLK6
It's not as if I hadn't entertained that idea once in a while - see the thread "WIP(?): A proposal for a VIC-20 with 60K RAM". That would also allow for RAM "under" the character ROM. With separated access paths for VIC and CPU.groepaz wrote:it would be so nice if you could map the e000-ffff block to ram as you can on c64.... but you cant
Just my focus got devoted to other projects in the meantime.
Re: Ultimem BLK6
i like how that thread (once again) derailed =)
i am not really interested in solutions that involve modding the hardware though... obviously then its possible (or i could just pop a custom rom into it...)
i am not really interested in solutions that involve modding the hardware though... obviously then its possible (or i could just pop a custom rom into it...)
I'm just a Software Guy who has no Idea how the Hardware works. Don't listen to me.
- Mike
- Herr VC
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Re: Ultimem BLK6
Of course it's not all that sensible to modify the mainboard if the intended result could also be achieved by an external solution.
That being said, my proposal in the other thread would have been 'nice to have', but on the other hand it had that smell of: "now that I've got the solution, I only need a problem". That's why I put that project on my low-priority list and ...
That being said, my proposal in the other thread would have been 'nice to have', but on the other hand it had that smell of: "now that I've got the solution, I only need a problem". That's why I put that project on my low-priority list and ...
... went for this route instead.groepaz wrote:or i could just pop a custom rom into it...
- eslapion
- ultimate expander
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Re: Ultimem BLK6
Well, it's possible with mods to the mainboard.groepaz wrote:it would be so nice if you could map the e000-ffff block to ram as you can on c64.... but you cant
Be normal.
Re: Ultimem BLK6
what about "no interested in hw mods" was not clear? OBVIOUSLY you can achieve all kind of things that "do not work" by modding the hardware.
i don't really like designing cartridges for specific things either i'd want to use stock setups, for vic20 probably even without using a floppy drive. the only hardware mod i find acceptable is RAM expansion (since those were incredibly common anyway).Of course it's not all that sensible to modify the mainboard if the intended result could also be achieved by an external solution.
I'm just a Software Guy who has no Idea how the Hardware works. Don't listen to me.
- eslapion
- ultimate expander
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Re: Ultimem BLK6
Honestly, where ? The OP only said...groepaz wrote:what about "no interested in hw mods" was not clear? OBVIOUSLY you can achieve all kind of things that "do not work" by modding the hardware.
That would be 'no'. I don't see any post from the user asking the original question specifying he(she) is not interested in HW mods. It remains the only solution I know of. BTW, I know I wouldn't do it.Does Ultimem support RAM at BLK6?
AFAIK, the vast majority of people using RAM expansion on their VIC-20 do it with a cartridge, not a hardware mod.i don't really like designing cartridges for specific things either i'd want to use stock setups, for vic20 probably even without using a floppy drive. the only hardware mod i find acceptable is RAM expansion (since those were incredibly common anyway).
Be normal.
Re: Ultimem BLK6
you did not reply to the OP, you replied to ME.Honestly, where ? The OP only said...
thanks, captain obviousAFAIK, the vast majority of people using RAM expansion on their VIC-20 do it with a cartridge, not a hardware mod.
I'm just a Software Guy who has no Idea how the Hardware works. Don't listen to me.
- eslapion
- ultimate expander
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Re: Ultimem BLK6
I was replying to that specific post from you.groepaz wrote:you did not reply to the OP, you replied to ME.
Overlooked this one 2 posts lower...
My mistake...i am not really interested in solutions that involve modding the hardware though.
Be normal.
- polluks
- Vic 20 Amateur
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Re: Ultimem BLK6
Nice tryMike wrote:I have a strong suspicion *why* you are asking this.
I was thinking about a GEOS implementation but it would require a jump table at $C000
VC20 [WGA103574] + UltiMem
- Mike
- Herr VC
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Re: Ultimem BLK6
I'd suppose not having room for a jump table at a certain address would be the least problem in attempting a port of GEOS.polluks wrote:I was thinking about a GEOS implementation but it would require a jump table at $C000
- polluks
- Vic 20 Amateur
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Re: Ultimem BLK6
Not really, without this RAM area you will lose compatibility, see Apple II GEOS. Stupid design decision.Mike wrote:I'd suppose not having room for a jump table at a certain address would be the least problem in attempting a port of GEOS.
VC20 [WGA103574] + UltiMem