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Memory upgrade for ZX Spectrum 16/48

velesoftvelesoft
edited April 2011 in Hardware
This is external memory upgrade for ZX Spectrum models with 16kB ram. Can be connect also to 48kB models, but need remove 8 dram chips (from sockets ideally).

zx48_to_128-EASY_6a.jpg

First prototype will work during 14 days.

Features of this upgrade:
+ connect external memory to adress space 32768-65535 in your ZX Spectrum
+ memory upgrade to 48kB,128kB,512kB or 1MB ram
+ paging port #7FFD at 90% compatible with ZX128 / Pentagon 128,512,1MB
+ switch for enable/disable extra memory (128kB / 1MB)
+ possibility use one or two SRAM 512kB chips (Pentagon 512kB / Pentagon 1024kB)
+ ram page 2 is mirrored to adress space 32768-49151 as on orig. ZX128
+ all external ram pages are fast (ULA no slow down CPU and code in high 32kB ram run always at full 3.5MHz as on Pentagon ZX clones)

- paging port #7FFD can't select second videoram, only first videoram is used.
- ram page 5 is not mirrored with first videoram (16384-32767), it's only classic ram page
Post edited by velesoft on
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Comments

  • kgmcneilkgmcneil
    edited March 2011
    Wow!... Will be keeping an eye on this one... ;)
  • TupinTupin
    edited March 2011
    Awesome, now my 48k+ has the option of becoming a 128k. Any idea on cost?
  • jegs2jegs2
    edited March 2011
    Looks cool - wonder if it would work on a T/S 2068 with twister board?
  • velesoftvelesoft
    edited March 2011
    jegs2 wrote: »
    Looks cool - wonder if it would work on a T/S 2068 with twister board?

    Yes, but you must disable internal ram from 32768-65535. (remove dram chips from socket or disable memory on port 244 before start basic = need modified ZX rom)
  • velesoftvelesoft
    edited March 2011
    Tupin wrote: »
    Awesome, now my 48k+ has the option of becoming a 128k. Any idea on cost?

    Will exist one version of board, but more variants of used components (more configurations):

    a) upgrade to ZX128 memory = 28 EUR

    b) upgrade to ZX128/Pentagon 512 memory = 33 EUR

    c) upgrade to ZX128/Pentagon 512/Pentagon 1024kB memory = 40 EUR

    Different configurations need different firmware for GAL chip.

    Next configurations:

    d) upgrade to ZX128 memory + 32kB rom = 35 EUR

    e) upgrade to ZX128/Pentagon 512 memory + 32kB rom = 39 EUR
  • fogfog
    edited March 2011
    Tupin wrote: »
    Awesome, now my 48k+ has the option of becoming a 128k. Any idea on cost?

    still beeper though..

    but it looks cool :) .. does it have pins to go into the 4116 slots underneath?

    I saw some dram pc thing, that worked that way. but it wasn't a board as such.
  • velesoftvelesoft
    edited March 2011
    fog wrote: »
    still beeper though..

    but it looks cool :) .. does it have pins to go into the 4116 slots underneath?

    I saw some dram pc thing, that worked that way. but it wasn't a board as such.

    It's external memory upgrade (your ZX don't need modification if contain only 16kB ram). This upgrade will similar as this:
    mb02mem-2.jpg

    Exist also next way for modify ZX16/48 to 128kB ram with both videorams, but it need hardware modifications on ZX board (use different dram chips and add next components).
  • Alien 8Alien 8
    edited March 2011
    fog wrote: »
    still beeper though..

    but it looks cool :) .. does it have pins to go into the 4116 slots underneath?

    I saw some dram pc thing, that worked that way. but it wasn't a board as such.

    So the AY magic would be the perfect companion piece.
  • zxbrunozxbruno
    edited March 2011
    If I remember correctly (from all the topics where it was mentioned before), there is no interface that will turn a 16K or 48K Spectrum into a "128K" which will work exactly like a standard 128K, not without the necessary internal modifications. I think that's what Velesoft is trying to say.

    The 128K upgrades that I've seen on several websites look like a big mess of wires and internal mods.

    Again, if I understand correctly, buying something like this will not allow a 16K, 48K or TS2068 user to suddently be able to run 128K-only software. I wish it was that simple...
  • Alien 8Alien 8
    edited March 2011
    Would it not operate in that 128K hybrid mode, with flashing K cursor, but access to 128K? If an AY magic is also present, as long as the Sound is programmed in machine code, it should be able to run 128K sofware, shouldn't it?
  • velesoftvelesoft
    edited March 2011
    Alien 8 wrote: »
    Would it not operate in that 128K hybrid mode, with flashing K cursor, but access to 128K?

    Yes, after connect upgrade(version without rom chip), then after power-on start ZX to 48 basic, but with enable 128 kB paging = same as USR 0 mode on original ZX128. In combination with Divide interface is possible use software for ZX128.

    If you use upgrade version with rom chip, then ZX start to 128 menu as original ZX128.
    Alien 8 wrote: »
    If an AY magic is also present, as long as the Sound is programmed in machine code, it should be able to run 128K sofware, shouldn't it?

    Yes.
  • Alien 8Alien 8
    edited March 2011
    I thought that would be the case. I asked if a 16K/48K could be upgraded to a 128K last year, and everybody (maybe not you) said no. Then somebody showed how they had done it internally. Well done for this extaernal add on. I don't need it, but I'm sure plenty of others do.
  • velesoftvelesoft
    edited March 2011
    External 128kB ram paging versus original ZX128 memory:

    Original ZX128 memory

    ZX memory adress space:
    0-16383=rom
    16384-32767=page 5
    32768-49151=page 2
    49152-65535=ram paging (pages 0-7)

    page 0 - fast ram
    page 1 - slow ram
    page 2 - fast ram, mirrored with zx ram 32768-49151
    page 3 - slow ram
    page 4 - fast ram
    page 5 - slow ram, mirrored with zx ram 16384-32767 (videoram 1)
    page 6 - fast ram
    page 7 - slow ram (videoram 2)



    128kB upgrade

    ZX memory adress space:
    0-16383=rom
    16384-32767=videoram 1
    32768-49151=page 2
    49152-65535=ram paging (pages 0-7)

    page 0 - fast ram
    page 1 - fast ram
    page 2 - fast ram, mirrored with zx ram 32768-49151
    page 3 - fast ram
    page 4 - fast ram
    page 5 - fast ram, this is new ram page (no mirrored with videoram 1)
    page 6 - fast ram
    page 7 - fast ram

    Theoretically is possible modify firmware for GAL to implement mirroring page 5 with adress space 16384-32767(videoram 1) and 99% of software for ZX128 will work on this upgrade. Only writing to page 5 in adress space 49152-65535 can't be visible in first videoram on TV, but software will work perfect.
  • zxbrunozxbruno
    edited March 2011
    So it does allow you to do all that without any internal modification? *very confused* If it does that's some of the greatest news I've heard in a long time!

    If it does, would it be possible to connect an AY interface together with that one?

    Velesoft, any plans on having an online shop where we can add items to the cart and then pay with Paypal?
  • Alien 8Alien 8
    edited March 2011
    zxbruno wrote: »
    So it does allow you to do all that without any internal modification? *very confused* If it does that's some of the greatest news I've heard in a long time!

    If it does, would it be possible to connect an AY interface together with that one?

    Velesoft, any plans on having an online shop where we can add items to the cart and then pay with Paypal?

    Well it looks to me as though the new device has an through connector, but if not, the AY magic certainly does have.
  • velesoftvelesoft
    edited March 2011
    zxbruno wrote: »
    So it does allow you to do all that without any internal modification?

    Yes, on ZX16kB it's :plug and play".
    On 48kB models need remove 8 dram chips from sockets (or disable signal CAS to fast dram chips)

    Photo of ZX Spectrum ISSUE TWO - removed dram chips = downgrade to ZX16kB :)
    issue2-16kB.jpg

    Photo of ZX Spectrum ISSUE 6a - removed dram chips = downgrade to ZX16kB :)
    issue6a-16kb.jpg

    zxbruno wrote: »
    If it does, would it be possible to connect an AY interface together with that one?
    Yes. All is enable.
    zxbruno wrote: »
    Velesoft, any plans on having an online shop where we can add items to the cart and then pay with Paypal?
    Can be. PayPal is now available.
  • rokoroko
    edited March 2011
    Photo of ZX Spectrum ISSUE 6a - removed dram chips = downgrade to ZX16kB
    Also downgraded to ULA 5C112E! This can't work, can it?
  • velesoftvelesoft
    edited March 2011
    roko wrote: »
    Also downgraded to ULA 5C112E! This can't work, can it?

    This is my old broken ZX boards. I only place ULA chip to issue 6a board. Yet is photos correct :)
  • Alien 8Alien 8
    edited March 2011
    I'm more interested in that Didaktik in the background.
  • velesoftvelesoft
    edited March 2011
    Alien 8 wrote: »
    I'm more interested in that Didaktik in the background.

    DIDAKTIK is Czech ZX clone based on russian "square ULA" - signed as ULA 1.

    Some russian ZX clones contain this ULA 1 chip. CPU clock at 4.0 MHz + wait from ULA.
  • Alien 8Alien 8
    edited March 2011
    velesoft wrote: »
    DIDAKTIK is Czech ZX clone based on russian "square ULA" - signed as ULA 1.

    Some russian ZX clones contain this ULA 1 chip. CPU clock at 4.0 MHz + wait from ULA.

    Does it work exactly like a ZX Spectrum? What comes on the screen on boot up?
  • velesoftvelesoft
    edited March 2011
    Alien 8 wrote: »
    Does it work exactly like a ZX Spectrum? What comes on the screen on boot up?

    Yes. Compatibility is very good. Also 48kB music for speaker sound correct. Multicolors work incorrect and port FF return value FF as ZX128+2A. Keyboard use same layout as ZX48 without extend mode...
  • Alien 8Alien 8
    edited March 2011
    velesoft wrote: »
    Yes. Compatibility is very good. Also 48kB music for speaker sound correct. Multicolors work incorrect and port FF return value FF as ZX128+2A. Keyboard use same layout as ZX48 without extend mode...

    And a real keyboard, by the looks of things.
  • velesoftvelesoft
    edited March 2011
    Alien 8 wrote: »
    And a real keyboard, by the looks of things.

    http://velesoft.speccy.cz/other/tesla-sezam1.jpg

    http://velesoft.speccy.cz/other/tesla-sezam2.jpg
  • velesoftvelesoft
    edited March 2011
    velesoft wrote: »
    This is external memory upgrade for ZX Spectrum models with 16kB ram. Can be connect also to 48kB models, but need remove 8 dram chips (from sockets ideally).

    zx48_to_128-EASY_6a.jpg

    First prototype will work during 14 days.

    Features of this upgrade:
    + connect external memory to adress space 32768-65535 in your ZX Spectrum
    + memory upgrade to 48kB,128kB,512kB or 1MB ram
    + paging port #7FFD at 90% compatible with ZX128 / Pentagon 128,512,1MB
    + switch for enable/disable extra memory (128kB / 1MB)
    + possibility use one or two SRAM 512kB chips (Pentagon 512kB / Pentagon 1024kB)
    + ram page 2 is mirrored to adress space 32768-49151 as on orig. ZX128
    + all external ram pages are fast (ULA no slow down CPU and code in high 32kB ram run always at full 3.5MHz as on Pentagon ZX clones)

    - paging port #7FFD can't select second videoram, only first videoram is used.
    - ram page 5 is not mirrored with first videoram (16384-32767), it's only classic ram page

    zx16to128upgrade7138.JPG

    zx16to128upgrade7139.JPG
  • velesoftvelesoft
    edited March 2011
    First upgrade work correct :) Tested games as ROBOCOP2, NAVY SEALS 1, NAVY SEALS 2, SWIV, TOTAL RECALL, PRINCE OF PERSIA, SPACE CRUSADE 128, SHADOW WARRIORS 128, PANG, LONE WOLF, ESCAPE FROM PLANET OF THE ROBOT MONSTERS, DIZZY 5 (128kB mode).

    http://velesoft.speccy.cz/other/zx16to128upgrade7143.JPG

    zx16to128upgrade7148.JPG
    zx16to128upgrade7149.JPG
    zx16to128upgrade7150.JPG

    Connect to ZX
    zx16to128upgrade7158.JPG
    zx16to128upgrade7160.JPG

    With DivIDE interface
    zx16to128upgrade7159.JPG
  • Mister BeepMister Beep
    edited March 2011
    Fog:
    Just get an AY interface. :)


    Velesoft:
    1) The discussion became a bit messy, so I don't fully get it.
    Could you specify if there will be a version that - connected to 16K ZX-bus - will give me full compatibility with Spectrum 128K software, without any additional internal modifications?
    2) In what speed will it work? ZX16, ZX128 or Pentagon? (Timing and stuff)?
    3) Will it be through/out/in device? I can see only one ZX-bus. I would look for something that is "ready to use" instantly, without wondering about additional interfaces. If possible.
    4) Will the gigasceen work? I mean - does it also provides 2 video-rams (necessary for full 128K compatibility)?

    If so, then I would surely buy this for my ZX16.
    ZX Spectrum 48K BEEPER Music:
    http://mister_beep.republika.pl/
  • velesoftvelesoft
    edited March 2011
    Mister Beep wrote: »
    Fog:
    Just get an AY interface. :)


    Velesoft:
    1) The discussion became a bit messy, so I don't fully get it.
    Could you specify if there will be a version that - connected to 16K ZX-bus - will give me full compatibility with Spectrum 128K software, without any additional internal modifications?
    2) In what speed will it work? ZX16, ZX128 or Pentagon? (Timing and stuff)?
    3) Will it be through/out/in device? I can see only one ZX-bus. I would look for something that is "ready to use" instantly, without wondering about additional interfaces. If possible.
    4) Will the gigasceen work? I mean - does it also provides 2 video-rams (necessary for full 128K compatibility)?

    If so, then I would surely buy this for my ZX16.

    1) External upgrade to ZX128 compatible memory is enable, but compatibility is about 85-90%. This interface can be connect to ZX16 without internal modifications ! Enable ZX128kB compatible memory but videoram switching is impossible, always shou only first videoram.

    2) Timing is 100% same as on ZX48. Code in all 128kB ram pages work at full speed 3.5MHz (as ram 32768-65535 on ZX48).

    3) Yes, this is only prototype. Through ZX bus can be add on back side.

    4) no, only first videoram are used.
  • MaccMacc
    edited March 2011
    Heres one for you, can I plug this into the expansion port of the Opus discovery? My speccy is pretty much screwed down tight with that now (literally) and if this can enable me to play 128k games using that, im up for it!
  • TMXTMX
    edited March 2011
    Alien 8 wrote: »
    What comes on the screen on boot up?
    starting screen (model '90):
    didmscr.th.jpg
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