ZX-UNO with 512Kb? How to turn it ON?

Dudas, cuestiones, sugerencias y peticiones en general sobre el proyecto / Questions and requests about the project
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YERZMYEY
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ZX-UNO with 512Kb? How to turn it ON?

Mensaje por YERZMYEY » 18 Jun 2016, 18:29

Hi,

is there any possibility to set up the 512Kb of RAM on ZX Spectrum?

The DAMN turbosound player (WildPlayer) requires 512KB (I don't know why, it's simply stupid) but it's not only the best TurboSound player - it's actually the only reasonable TS player on ZX, so I was wondering - maybe I can turn the 512Kb of RAM on ZX-UNO somehow?

Regards.
Y

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antoniovillena
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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por antoniovillena » 18 Jun 2016, 18:38

Yes. You have access to 512kb with a rooted ROM

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Quest
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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por Quest » 18 Jun 2016, 18:46

But.... the ROM in use reside in the SRAM, correct? so, the whole 512K are not fully available. Or I am mistaken?
http://www.zxuno.com
ZX-Uno · Clon de ordenador ZX Spectrum basado en FPGA

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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por YERZMYEY » 18 Jun 2016, 19:57

Hmmm. I suspect the player wouldn't mind even 256K or even an info about 512Kb (and not entirely accessible RAM in reality) but I cannot test it, as I'm only a regular use, so I even don't know what "a rooted ROM" is, hehe.

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antoniovillena
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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por antoniovillena » 18 Jun 2016, 21:49

A rooted ROM is a ROM with LOCK/MASTERCONF inactive.

http://www.zxuno.com/wiki/index.php/ZX_Spectrum

So you can enter in boot mode and access to 512Kb of RAM, mapped in $C000-$FFFF. In boot mode the ROM is writable, so nobody forbid you to overwrite the ROM and use full 512Kb on your game.

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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por YERZMYEY » 19 Jun 2016, 20:28

If You'd find some time, I would be grateful if You could write for me, step by step, and idiot-guide how to do it, including some links to the files if such would be required.

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antoniovillena
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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por antoniovillena » 19 Jun 2016, 21:26

The 512Kb access is with the ZX-Uno paging. The only software that uses this paging method is the ZX-Uno BIOS. So these 512Kb are only available for new designs. If you try to work with more than 128K with another software like WildPlayer, you need to implement the paging method used in Scorpion or the russian clone in the core. These methods are not implemented yet.

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antoniovillena
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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por antoniovillena » 19 Jun 2016, 21:31

These seems to be the paging methods used by russian clones: Source

Pentagon 512 kB
port 7FFD: (adressation 0xxxxxxx xxxxxx0x )
D0 = bank 0 ;128 kB memory
D1 = bank 1 ;128 kB memory
D2 = bank 2 ;128 kB memory
D3 = videoram
D4 = rom
D5 = disable paging
D6 = bank 3 ;256 kB memory
D7 = bank 4 ;512 kB memory

Pentagon 1024 kB
port 7FFD: (adressation 01xxxxxx xxxxxx0x )
D0 = bank 0 ;128 kB memory
D1 = bank 1 ;128 kB memory
D2 = bank 2 ;128 kB memory
D3 = videoram
D4 = rom
D5 = bank 5 ;1024 kB memory (if D2 of port EFF7=0)
D6 = bank 3 ;256 kB memory
D7 = bank 4 ;512 kB memory
port EFF7: (adressation 1110xxxx xxxx0xxx )
D2 = 1 - set 128 kB mode
0 - enable 1MB memory
(if D2 of port EFF7=1 then D5 of port 7FFD is used for disable paging)
D3 = 1 - disable rom and connect ram page 0 in adress space 0-3FFF

Scorpion 256 kB
port 7FFD: (adressation - 01xxxxxx xx1xxx01 )
(adressation in REALSPECTRUM emul is also different ) :v2_wacko:
D0 = bank 0 ;128 kB memory
D1 = bank 1 ;128 kB memory
D2 = bank 2 ;128 kB memory
D3 = videoram
D4 = rom
D5 = disable paging
D6 = unused
D7 = unused
port 1FFD: (adressation - 00xxxxxx xx1xxx01 )
D0 = 1 - disable rom and connect ram page 0 in adress space 0-3FFF :v2_conf3:
(UNREAL SPECCY emulator set after OUT 1FFD,1 ram page 0 to low 16kB, but REALSPECTRUM emulator set ram page 8 to low 16kB :v2_jawdr: )
D4 = bank 3 ;256 kB memory
D6 = unused
D7 = unused

Scorpion 1024 kB
port 7FFD: (adressation - 01xxxxxx xx1xxx01 )
(adressation in REALSPECTRUM emul is also different ) :v2_wacko:
D0 = bank 0 ;128 kB memory
D1 = bank 1 ;128 kB memory
D2 = bank 2 ;128 kB memory
D3 = videoram
D4 = rom
D5 = disable paging
D6 = unused
D7 = unused
port 1FFD: (adressation - 00xxxxxx xx1xxx01 )
D0 = 1 - disable rom and connect ram page 0 in adress space 0-3FFF
D4 = bank 3 ;256 kB memory
D6 = bank 4 ;512 kB memory
D7 = bank 5 ;1024 kB memory

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antoniovillena
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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por antoniovillena » 19 Jun 2016, 22:28

I think a russian 256Kb can be implemented in ZX-Uno. The question is, what is more extended? Pentagon with 256Kb or Scorpion 256

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Re: ZX-UNO with 512Kb? How to turn it ON?

Mensaje por YERZMYEY » 19 Jun 2016, 22:32

Aaaaaaah, I see - sow for now it's impossible for a regular user.
OK then - so if You guys would be bored enough, You might consider making such an update in the firmware, hehehehehehe. :)

As for the machine, I would definitely go for Pentagon in this case, than Scorpion.

Anyway, thanks for the explanation.

Responder