QL-VGA

[mk79]

Since the NTSC flag in the 8301 allows 60Hz output, would that simplify things? Or is the 60Hz tied strictly to different resolutions?

If you've got some 60Hz output you can probably get away with just using a line doubler (like OSSC) and have a standard compliant output, too. But then you have all the problems that a 60Hz poll on a QL would imply, most software was never really designed for this.

[Dave]

As far as I know, there isn't a version of the 8301 ULA that actually implements this. It was obviously planned but may never have been implemented.

Actually I tried "POKE hex('18063'),64" on my German issue 6 or something QL and the display gets weird and the poll frequency changes to 60Hz, so I think NTSC with the 8301 is a thing

Yep.

[Nasta]

As far as I know, there isn't a version of the 8301 ULA that actually implements this. It was obviously planned but may never have been implemented.

Actually I tried "POKE hex('18063'),64" on my German issue 6 or something QL and the display gets weird and the poll frequency changes to 60Hz, so I think NTSC with the 8301 is a thing

Inreresting, I've seen several versions of the 8301, but none had that. Does the NTSC flag work on both MODE4 and MODE8? It would have to limit the number of display lines so in 60Hz there would be a lot of vertical overscan.
Can you check some more so I'll add it to the 8301 documentation thread? Can you tell me what the markings on your 8301 are?

[papanillu]

Hi
I should buy one of these, (or maybe two) if they become avaiable.

[mk79]

Interesting, I've seen several versions of the 8301, but none had that. Does the NTSC flag work on both MODE4 and MODE8? It would have to limit the number of display lines so in 60Hz there would be a lot of vertical overscan.
Can you check some more so I'll add it to the 8301 documentation thread? Can you tell me what the markings on your 8301 are?

I didn't check all my ZX8301 (got 10 or so), but the 6 or so I did check all have date codes from 1985:

The line timings don't change at all, it just displays less lines to meet the 60Hz. PAL mode (pink is CSYNC, blue is BLUE with a completely white picture):

Same view with NTSC. Apparently there are now about 192 white lines (the counter is a btit jumpy between 190 and 192):

The vsync front porch is apparently 32 lines:

The back porch curiously seem to be 34 lines

All a bit weird but that's what my scope says at least. Mode 4 and mode 8 seem to be identical timing wise.

Cheers, Marcel

[NormanDunbar]

Hi Marcel,

I always hated you for being so young, talented and for having a brain the size of a planet, but now I find out that you have a Rigol scope too.

I have to make do with a EspoTek Labrador. https://espotek.com/labrador/product/es ... dor-board/

However, I have two!

Cheers,
Norm

PS. Joking of course!.

[janbredenbeek]

Interesting, I've seen several versions of the 8301, but none had that. Does the NTSC flag work on both MODE4 and MODE8? It would have to limit the number of display lines so in 60Hz there would be a lot of vertical overscan.
Can you check some more so I'll add it to the 8301 documentation thread? Can you tell me what the markings on your 8301 are?

I didn't check all my ZX8301 (got 10 or so), but the 6 or so I did check all have date codes from 1985

On my D15 QLs, the POKE has no effect. But your 8301 is a CLA2345, this is different from mine (CLA2310, date code 8453).
(I have two issue 5 QLs and two issue 6, all are plain UK models but some have a 220V power supply rather than 240V).

Jan

[mk79]

I always hated you for being so young, talented and for having a brain the size of a planet, but now I find out that you have a Rigol scope too.

Now, if I had done this using one of the scopes at work, ranging from some 4000€ Agilents to 15000€ LeCroys, I would understand the envy, but the Rigol? It's less than 400€ nowadays, what are you waiting for Of course mine was a business expense and paid for by QL-SD sales, so thanks everybody

Cheer, Marcel

[mk79]

On my D15 QLs, the POKE has no effect. But your 8301 is a CLA2345, this is different from mine (CLA2310, date code 8453).
(I have two issue 5 QLs and two issue 6, all are plain UK models but some have a 220V power supply rather than 240V).

Interesting. I only have German QLs, which automatically seems to imply that I only have issue 6 QLs. I've shot a few ULAs during my experiments, but the replacement chips were all CLA2345, too. Do your issue 6 QLs also have the 2310?

Cheers, Marcel

[janbredenbeek]

On my D15 QLs, the POKE has no effect. But your 8301 is a CLA2345, this is different from mine (CLA2310, date code 8453).
(I have two issue 5 QLs and two issue 6, all are plain UK models but some have a 220V power supply rather than 240V).

Interesting. I only have German QLs, which automatically seems to imply that I only have issue 6 QLs. I've shot a few ULAs during my experiments, but the replacement chips were all CLA2345, too. Do your issue 6 QLs also have the 2310?

Yes, these are Issue 6 QLs with (originally) JS ROMs.
But AFAIK the German QLs were made by Samsung (SG-xxxxxx serial numbers with Issue 7 boards)?

There's a lot of info on build standards on Urs König's page here: http://www.sinclairql.net/build_standards.html

cheers, Jan.