Autor Wątek: Karabas-Nano  (Przeczytany 611 razy)

dakidski

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Karabas-Nano
« dnia: 2019.10.20, 16:30:57 »
New ZX Spectrum 128k-clone from Ukraine! Presenting Karabas-Nano rev.C made by Andy Karpov ( https://github.com/andykarpov/karabas-nano ). I reckon it is the world's smallest ZX Spectrum 128k-clone WITH a physical keyboard! I will be testing it during the coming week. (Real ZX Spectrum included for scale.)

More pictures:
https://www.facebook.com/retrogamingdenmark/posts/2179762428990375

Maryjan

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« Odpowiedź #1 dnia: 2019.10.20, 18:54:33 »
I'ts to small.
Not for my eyes :)

"... podobno są dwie szkoły, Falenicka i Otwocka."

trojacek

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« Odpowiedź #2 dnia: 2019.10.20, 19:21:20 »
IMHO, it's been made for fun, not for use.
Yes - too small. Who's gonna use this keyboard? Kids, dwarves? My fingers are too thick for it.
And no edge connector - bummer!
Furthermore, I see only one RAM chip, so I don't suppose any standard contention model is implemented.

Klaud

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« Odpowiedź #3 dnia: 2019.10.20, 20:21:51 »
Bo to blizsze Pentagonowi niż Toastrackowi.
KL
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dakidski

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« Odpowiedź #4 dnia: 2019.10.20, 23:16:38 »
IMHO, it's been made for fun, not for use.
Yes - too small. Who's gonna use this keyboard? Kids, dwarves? My fingers are too thick for it.
And no edge connector - bummer!
Furthermore, I see only one RAM chip, so I don't suppose any standard contention model is implemented.
The keyboard is small, but it's there.
There is actually an edge connector, or ZX Bus. But you need an adapter, which I don't have yet. The ZX Bus is on the middle top, between tape in/out and the power supply. See the schematics here: https://raw.githubusercontent.com/andykarpov/karabas-nano/master/docs/photos/revC-1.png
I'm not clever enough to answer you about the ram contention, but maybe the answer can be found here: https://github.com/andykarpov/karabas-nano

trojacek

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« Odpowiedź #5 dnia: 2019.10.21, 00:15:29 »
The keyboard is small, but it's there.

Yes, but what really counts is usability, IMHO.

Cytuj
There is actually an edge connector, or ZX Bus. But you need an adapter, which I don't have yet. The ZX Bus is on the middle top, between tape in/out and the power supply. See the schematics here: https://raw.githubusercontent.com/andykarpov/karabas-nano/master/docs/photos/revC-1.png

That's a good news, thanks for this link.

Cytuj
I'm not clever enough to answer you about the ram contention, but maybe the answer can be found here: https://github.com/andykarpov/karabas-nano

I am no expert on VHDL, but I have looked at the code on github, and my first impression was that the whole RAM is contended! I will review it once I have a sleepless night :)
What I also noticed, there is an AY implementation for AVR mentioned on github, but no AVR can be found on the PCB. Or maybe it is soldered on the oposite side of the PCB, thus invisible in these pictures above?
« Ostatnia zmiana: 2019.10.21, 01:43:12 wysłana przez trojacek »

Klaud

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« Odpowiedź #6 dnia: 2019.10.21, 07:29:56 »
I would worry about timings that are not compliant with the 128K model at all. The CPU clock is driven by CPLD which divides 28MHz by 8. So the CPU clock is 3.5MHz only. On the first look into the VHDL code, both screen counters (vertical and horizontal) have been set to 48K model values. The extension port is off standards, even not in ZX-UNO style. And on the top of these an emulation of AY chip is based on Atmega8 with 20MHz clock, that does not sound to my taste at all. 

Anyway you guys did an excellent job and created an interesting clone in very small form factor.  :)
« Ostatnia zmiana: 2019.10.21, 09:27:28 wysłana przez Klaud »
KL
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dakidski

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« Odpowiedź #7 dnia: 2019.10.21, 20:06:18 »

Cytuj
That's a good news, thanks for this link.
Actually this is the correct link for the schematics:
https://github.com/andykarpov/karabas-nano/blob/master/docs/karabas-nano-revC.pdf

Cytuj
What I also noticed, there is an AY implementation for AVR mentioned on github, but no AVR can be found on the PCB. Or maybe it is soldered on the oposite side of the PCB, thus invisible in these pictures above?
AY AVR is soldered on the back, see the facebook-link for picture of the backside.

dakidski

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« Odpowiedź #8 dnia: 2019.10.21, 20:09:05 »
Cytuj
Anyway you guys did an excellent job and created an interesting clone in very small form factor.  :)
I did nothing. Andy Karpov created it alone. I was just lucky enough to get my hands on one.

Both the cpld- and avr-code was updated today. I programmed both onto my Nano.