32k benefits and software?

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Its1982again
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32k benefits and software?

Post by Its1982again »

I've just bought a machine with 32k internal RAM to add to my collection. I'm wondeing whatbthe benefits are and if there's any specific software around that makes the most of this. I've got the Quicksilva games on SD and wondered if the HRG would work with the extra memory, or any other games people know about? Cheers guys, Dave.
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1024MAK
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Re: 32k benefits and software?

Post by 1024MAK »

Part of the answer will depend on where this is mapped to.

This topic discusses the address decoding performed by the ZX81/TS1000 ULA.

The vast majority of games use only RAM between 0x4000 to 0x7FFF (16384 to 32767) which is the normal 16k byte RAM area. This area is cleared by BASIC as part of the start-up code.

Some applications use the unused space between the top of the ROM and the normal RAM area. That is 0x2000 to 0x3FFF (8192 to 16383). BASIC ignores this 8K byte area. Additional logic is needed to disable the BASIC ROM and enable RAM in this area.

Above 0x7FFF (32767) RAM can either carry on, or start again at 0xC000 (49152) with a gap in between. Again, extra logic is needed to disable the BASIC ROM and enable RAM in this area, or to only enable the RAM for data (the ‘echo’ of the display file RAM must be allowed to be read by the Z80 for instruction reads otherwise the display system will no longer work). In either case, BASIC will ignore these areas of RAM at startup. If the RAM continues above 0x7FFF (32767) without a gap, you can POKE a system variable so that BASIC will use this RAM.

Or maybe a 32k RAM chip has been used, but only 16k bytes is actually able to be used.

Did the seller say?

Mark
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Its1982again
Posts: 78
Joined: Tue Aug 04, 2020 6:26 pm

Re: 32k benefits and software?

Post by Its1982again »

Just said 32k sram internal mod and HI-RES ready. ??? Also back porched to composite mod off original feranti chip, but I have a standard one comp modded so that's no issue. Cheers for the reply. It should arrive this week so I'll know more then.
ZX80 (white psu)
Issue 1 ZX81
32k comp mod ZX81 filesixty keyboard
Issue 1 Spectrum
Issue 2 Specrum
Toastrack
Issue 3 in Lo-Profile keyboard
Harlequin 128
DivMMC future
vdrive
TZXduino
ZX printer
Alphacom printer
Lardo Boffin
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Re: 32k benefits and software?

Post by Lardo Boffin »

Rudedog Retro? They seem to be about the only people other than me who sells refurbished zeddies regularly.
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ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
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TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Its1982again
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Re: 32k benefits and software?

Post by Its1982again »

Yep. I wanted to see what the extra memory would give me and got it for a decent price. My other standard one is gonna go to Mutant for a fix so I'll have the 32k to mess around with. Still looking for a ZXPand but to no luck yet.
ZX80 (white psu)
Issue 1 ZX81
32k comp mod ZX81 filesixty keyboard
Issue 1 Spectrum
Issue 2 Specrum
Toastrack
Issue 3 in Lo-Profile keyboard
Harlequin 128
DivMMC future
vdrive
TZXduino
ZX printer
Alphacom printer
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mrtinb
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Re: 32k benefits and software?

Post by mrtinb »

If you need a storage solution, and cannot wait for the next batch of ZXpand+s, there's a new cheap storage solution on the German forum.

It's the ZX-Wespi. You just buy an ESP32, and connect 4 wires to your ZX81 PCB. (Plus a tantalum capacitor, and three resistors.) It's a very simple circuit you can make on a perfboard.

When you type the command LOAD"", the ZX-Wespi detects this, and displays a menu with all software stored in it's internal flash. The software can then be loaded with a keypress. It's quite fast, as the menu has a buitin fastloader. Software is loaded in seconds.

Software is added via a webbrowser connected to the Wespi's builtin server.

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Its1982again
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Re: 32k benefits and software?

Post by Its1982again »

Looks a neat thing. I'm good with the TZXduino for now tho. I'l be getting a ZXPand+ once the new batch gets issued.
ZX80 (white psu)
Issue 1 ZX81
32k comp mod ZX81 filesixty keyboard
Issue 1 Spectrum
Issue 2 Specrum
Toastrack
Issue 3 in Lo-Profile keyboard
Harlequin 128
DivMMC future
vdrive
TZXduino
ZX printer
Alphacom printer
User avatar
stefano
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Re: 32k benefits and software?

Post by stefano »

There's also campus lisp ..

viewtopic.php?t=1630
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