Hi Everyone

Introduce yourself to your fellow forum members - what was your journey into the Sinclair world?
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Baggey
Posts: 9
Joined: Fri Aug 04, 2023 1:13 pm

Re: Hi Everyone

Post by Baggey »

1024MAK wrote: Mon Aug 07, 2023 2:41 pm I trust that you know that /INT is connected to address line A6?

And that the display code uses the R (refresh) register in an unconventional manner.

This and the circuitry around the /WAIT and /HALT pins are used by the display system.

Mark
No i didn't know any of this. Could you elaborate in more detail if possible. The video may show some errors but its sort of working.

Kind Regards Baggey
Running a PC that just Aint fast enough!? i7 Quad core 16GB ram 1TB SSD. DID Technology stop! Or have we been assimulated!

ZX Spectrum 48k, C64, ORIC Atmos 48K, Enterprise 128K, The SID chip. Im Misunderstood!
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1024MAK
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Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: Hi Everyone

Post by 1024MAK »

Have a read of the Video Tutorial by Wilf Ritger here.

Note: by default the pages at the linked to web site may not display correctly, so switch your character set to "western" for correct display.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp

:!: Standby alert :!:
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Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer being good this year.
dr beep
Posts: 2231
Joined: Thu Jun 16, 2011 8:35 am
Location: Boxmeer

Re: Hi Everyone

Post by dr beep »

Baggey wrote: Tue Aug 08, 2023 11:13 am
My Display isn't working correctly and the aliens aren't dropping to the floor? This could be because im not triggering interrupts or because the display timing isn't correct they may be linked to this.
The dropping on the screen is not a part of displaying the screen.
If the aliens must drop it is part of the game.

You might have a wrong emulated opcode.

As for perfect display: you need to read Wilf Rigters page about the screen.

Timing of the code is relevant (each opcode must be calculated) and then the display of the data pointed by I and R
in highmemory is the only display part.

Timing is crucial if you want to run my 1K hires games.
dr beep
Posts: 2231
Joined: Thu Jun 16, 2011 8:35 am
Location: Boxmeer

Re: Hi Everyone

Post by dr beep »

1024MAK wrote: Tue Aug 08, 2023 1:43 pm Have a read of the Video Tutorial by Wilf Ritger here.

Note: by default the pages at the linked to web site may not display correctly, so switch your character set to "western" for correct display.

Mark
Here is another link you can select your language
https://8bit-museum.de/heimcomputer-2/s ... ay-system/
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Baggey
Posts: 9
Joined: Fri Aug 04, 2023 1:13 pm

Re: Hi Everyone

Post by Baggey »

Thanks for the Links! So i try and throw a ZX80 Rom in and it dosent work!?

Just realized VARS is different and there appears to be no CDFLAG. So does the ZX80 run in FAST all the time ie 65000 instead of the 16000 that the ZX81 does? :oops:

Currently searching for descent links on the ZX80 :geek:

Ive read the Hi-Res stuff but i cant find anywhere were the screen DFILE starts and what layout it's in?

Manic Miner loads and i can see the Screen in my live Memory Mapper which helps a lot of the time i can zoom in and get the DFILE address that way but is it just rastered? I think not. Im confused but im understanding that the I register points to the CHARS but we should only read 8 pixels but im not glueing how it's laid out. is it line by line or character by character etc..

Any help much appreciated :roll:

Kind Regards Baggey
Running a PC that just Aint fast enough!? i7 Quad core 16GB ram 1TB SSD. DID Technology stop! Or have we been assimulated!

ZX Spectrum 48k, C64, ORIC Atmos 48K, Enterprise 128K, The SID chip. Im Misunderstood!
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1024MAK
Posts: 5238
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: Hi Everyone

Post by 1024MAK »

The ZX80 does not have a ‘SLOW’ mode. So yes, it’s effectively running in ‘FAST’ mode. This is because it does not a NMI generator. Hence why you will find descriptions about the display flickering every time you press NEW LINE…

The 4K byte ROM also knows nothing about the extra video functionality from the ZX81 ULA.

The link in my first post in this topic does provide some ZX80 information. Please read through the linked web page.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer being good this year.
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