How I found some original Atari ST ASIC designs

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Steven Seagal
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Re: How I found some original Atari ST ASIC designs

Postby Steven Seagal » Tue Dec 05, 2017 8:15 pm

ijor wrote:STFm GLUE considers BLANK as a relevant signal for monochrome as well (even when at board level is not) and applies similar logic as for the color frequencies. Here, according to those schematics, high rez asserts BLANK regardless the horizontal position, as you are saying. Switching to color will not clear BLANK automatically, not until the counter reaches the correct value. So it depends at which point you switched to mono.

Note that SHIFTER blacks the RGB signals at high rez anyway.


Hi, no surprise, the same happens for vertical blank.
As I've started writing the video logic in C, I was wondering if you could give us the high resolution values in comparators for BLANK, horizontal and vertical, on the STF, if you have them?

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Re: How I found some original Atari ST ASIC designs

Postby ijor » Wed Dec 06, 2017 12:40 am

Steven Seagal wrote:As I've started writing the video logic in C, I was wondering if you could give us the high resolution values in comparators for BLANK, horizontal and vertical, on the STF, if you have them?


Give me a few days. If I forget, don't hesitate to remind me :)

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Steven Seagal
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Re: How I found some original Atari ST ASIC designs

Postby Steven Seagal » Wed Dec 06, 2017 7:10 am

Oh no, never mind. It was in case you already had notes for that, it can wait.

EDIT In fact your Shifter insights would be more useful for the moment.

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Re: How I found some original Atari ST ASIC designs

Postby Zarchos » Wed Dec 06, 2017 10:13 am

Steven, sorry if you gave the details before and shame on me I haven't read them, but I am curious to know what is your background, in terms of computer science, for being so, well, excellent at what you do ?
I am, for sure, very impressed.
The ST people, honestly, you have always impressed me by how far you have been into the indepth knowledge of your machines, and the various achievements demonstrated.
Atari 1040 STE+SATAN, 520ST, 800xl, xegs, Amiga 500, 2000 with 68020, Archimedes, RISC PCs + Iyonix, Omega, BBC B, Atom, Electron, ZX 81, Spectrum 48/128/+2/+3, Speccy2010, Russian clones, Sam Coupe, V6Z80P, QL with accelerators, Enterprise 128, Einstein inc 256, Oric Atmos, MSX 1, 2, Thomson MO5, Amstrads inc CPC+, C 16, 64, 128, VG5000, Apple IIGS and more ! Yes I want to create a museum when I retire.

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Steven Seagal
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Re: How I found some original Atari ST ASIC designs

Postby Steven Seagal » Wed Dec 06, 2017 12:39 pm

Hi, maybe it's not the right thread.
I gave the answers you're looking for in an ST demo:

Image
(click for better visibility)
http://ataristeven.exxoshost.co.uk/Steem_demos3.htm#SSE3.5

"Getting somewhat chubby for action movies... Steven Seagal decided to do ST emulation instead"


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