Pseudo HR prototype

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
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stefano
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Pseudo HR prototype

Post by stefano »

I'm trying to add support for Pesudo High Resolution to z88dk.
I must say it is not easy at all but I'm aleady at an average status of the project, even if it there is still a lot to do.
The horizontal resolution is fixed (128) but the vertical one can be changed by adjusting a single parameter and rebuilding the whole library. I chose to keep 96 rows by default.

I'm attaching here a first test program, I need as many people as possible to try it on a real ZX81 on different TV sets. The frequency generation is customized and I'm not convinced it is good for all the configurations existing in the real world!

Any ZX81, standard or modified, should be good for this check. Different ROM versions (e.g. from the latin America) may garble the picture, but it is ok, as long as the picture is stable.
rndsphere.p
(6.91 KiB) Downloaded 267 times
Moggy
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Re: Pseudo HR prototype

Post by Moggy »

I have four types of TV set so will try this tonight and report back.
Last edited by Moggy on Fri Apr 03, 2020 11:04 pm, edited 1 time in total.
Moggy
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Re: Pseudo HR prototype

Post by Moggy »

The first picture is a standard CRT colour TV with a composite input.
The ZX81 is an issue three with 2c210 ULA and a ZXCCB composite video board for output with a standard Sinclair ROM and a ZXpand issue 5.

The second picture Is a small portable B/W CRT TV with a UK standard aerial input.
The ZX81 is an unmodified issue one with a 2c184 ULA , modulator output a ROM marked NEC and a ZXpand +.

The third picture is an LCD TV with a composite input, the ZX 81 is a modified fan cooled issue one fitted with 2c210 ULA , 2 speed BASIC ROM, Andy Rea's UDG board and a ZXpand issue 3.
The UDG board did not effect the display when switched in or out nor did the modified ROM.

Three different TV's three different ULA's and all seems to work ok with slight differences in the pixel distribution.

Any distortions in the picture is down to my sloppy camera work nothing else and the pictures were all stable.

Hope this is of some use.

LATE EDIT.

Added one more picture which shows the modified ZX81 used for the LCD TV but this time fitted with Andy Rea's new ULA replacement.connected to a small portable B/W CRT TV which is unusual as it has a composite input..
Regards.

Moggy.
Attachments
Colour CRT TV composite.
Colour CRT TV composite.
B/W CRT TV with a UK standard aerial input.
B/W CRT TV with a UK standard aerial input.
LCD TV composite input.
LCD TV composite input.
B/W CRT TV composite input.new type ULA
B/W CRT TV composite input.new type ULA
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stefano
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Re: Pseudo HR prototype

Post by stefano »

It's fantastic news, thankyou for the comprehensive tests !
The library should be able to self - adjust the timing in a range between, say 2 to 200 rows.
I'm currently debugging, there's still a lot of bugs and missing things but sure this is encouraging!
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stefano
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Re: Pseudo HR prototype

Post by stefano »

is the picture on top or centered? EO centres it, It's obviously better but I couldn't understand why it happens.
Moggy
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Re: Pseudo HR prototype

Post by Moggy »

stefano wrote: Sat Apr 04, 2020 11:24 pm is the picture on top or centered? EO centres it, It's obviously better but I couldn't understand why it happens.

Hi Stefano.

The pictures are centred as normal, I just clipped them in Photoshop to show the relevant detail, I see them on real zeddy as I would think you see them in emulator.
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siggi
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Re: Pseudo HR prototype

Post by siggi »

Hi Stefano

this is a picture on a good LCD colour monitor, generated by a ZX81NU (no ULA), having a BIGBANG-ROM. The pixels seem to be identical, so maybe the
rom region, which is used as "character generator" by your program, is not modified compared to the original Sinclair rom. The picture ist stable and does not flicker
IMG_6260_1024x768.JPG
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Siggi
My ZX81 web-server: online since 2007, running since dec. 2020 using ZeddyNet hardware
http://zx81.ddns.net/ZxTeaM
bola_dor
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Re: Pseudo HR prototype

Post by bola_dor »

Looks very promising,,
I have Two CZ1000 that are 2k TS1000 ISS3 but at 50Hz designed to run on PAL-N channel 2 or 3, Sadly the one with the original RF modulator is not working (yet) but I can test on the other one with a buffer composite mod, I don´t have a CRT TV either,, as I said these are 50HZ so I don´t expect much different result as you already have,, I´ll find the time on weekend..promise..
EO 60HZ.png
EO 60HZ.png (6.41 KiB) Viewed 5403 times
this is Eighty One at 60HZ,,
50hz looks ok but I think you already new.
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come :D
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stefano
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Re: Pseudo HR prototype

Post by stefano »

the library development is being harder than expected, I've been debugging putsprite for a couple of weeks and still I don't see what's wrong!
same for plotting and line drawing. . I'm suspecting a memory leak or corrupted registers because there is no direct connection between the bugs and the changes I make in the test programs.
It is surprising the hardware check went so well, I should prepare something to test a different number of lines, to be sure I'm using a correct formula, but I'll take care of it in the future.
I'm thinking to complete the buffers allocation first, to try to avoid odd memory conflicts and add a little bit of useful and working code : people is already using this crap to write games!
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stefano
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Re: Pseudo HR prototype

Post by stefano »

Pushing the library at its maximum: 200 rows could still work. :twisted:
rndsphere_200.p
(3.92 KiB) Downloaded 253 times
Program looks smaller because it is now able to allocate the screen buffer automatically (lowering SP).
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