Is 32k expansion common among VIC-20 enthusiasts?

[siccoyote]

I like to see the amazing things people are able to do unexpanded, but I have a 32k/35k cart so I like the more expansive games that can put it more in competition with stuff like the speccy.

Not that bothered about using actual disks, even though I have a 1541, prefer to just load it up in the sd2iec. Wish more of the demos were adapted to use with that as my actual blank floppies keep dying.

[Witzo]

$9400-$a000 for the extra 3K in a 35K expansion??

[Mike]

$9400-$a000 for the extra 3K in a 35K expansion??

To cut the story short: no, it's $0400..$0FFF. The same position the +3K RAM expansion takes on its own, as I already wrote.

[Witzo]

$9400-$a000 for the extra 3K in a 35K expansion??

To cut the story short: no, it's $0400..$0FFF. The same position the +3K RAM expansion takes on its own, as I already wrote.

Thanks for pointing it out for me. The thing you already wrote is, I think, "To the same place it'd go on its own.". I misunderstood it at first, sorry if my question bothered you.

My earlier confusion was from forgetting to count that 32KB was already used up with just block 1, 2, 3 and 5; overlooking block 0.

[Mike]

No worries.

For example, my CGA panning viewer requires a +35K RAM expansion. I explicitly pointed out there, that merely +32K isn't sufficient:

+35K RAM are required: yes, that means +24K in BLK1..3, +8K in BLK5 *and* +3K in RAM1..3!

Same thing applies to Kweepa's VIC-Doom. He also uses +35K, and that is the maximum RAM expansion regularily possible on the VIC-20 which doesn't rely on banking.

Following up on Gorf's questions: Some newer cartridges supply RAM also in I/O2 and I/O3 (most notably, Ultimem). This would allow for another extra +2K in the range $9800..$9FFF. Main issue: this address range is intended for use as registers for the respective cartridge firmware, and inconsiderate writes (and even reads!) may have unforeseeable side effects - harmless: 'just' resetting the VIC-20, more strange: re-mapping the extra RAM, eventually leading to crashes as running programs see their memory disappear, even more strange: overwriting preferences/options stored in NVRAM, show-stopping: erasing any Flash-Memory present, be it the cartridge firmware itself or attached SD-Cards, in case the cartridge happens to implement a Flash File System.

If programs ever begin to use that area regularily for the puny amount of an extra 2K RAM, this will lead to a huge amount of annoyance of IEEE-488, 40/80-Column, Mega-Cart, FE3 and Ultimem cartridge users. IMO, the only legit user of the I/O address range is the cartridge firmware.

[siccoyote]

[Witzo]

No worries.

Pfew
I guess my 32KB expansion will suffice for most, and I'll use an emulator for the really big programs.

[orion70]