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Re: STE video chip

Posted: 26 Oct 2023 20:25
by exxos
I've done a quick video to explain all this in a nutshell.



Yes I have a cold. Yes I'm half asleep. Yes I need a better cam. And no I don't care :P

Though if I ever get my workshop straight. I may invest in a better recording setup.

Re: STE video chip

Posted: 26 Oct 2023 20:47
by JezC
Nice video - and, no I'm not being sarcastic!

Explains the problem & shows the difference very nicely.

So I need to check which version of the shifter is in my STEs & only test those with the 1712 shifters (if I have any)

:thumbup:

Re: STE video chip

Posted: 26 Oct 2023 20:49
by exxos
JezC wrote: 26 Oct 2023 20:47 So I need to check which version of the shifter is in my STEs & only test those with the 1712 shifters (if I have any)
It's worth checking the 588 just to verify the graphics only fail on the 1712.

Re: STE video chip

Posted: 26 Oct 2023 21:09
by JezC
exxos wrote: 26 Oct 2023 20:49
JezC wrote: 26 Oct 2023 20:47 So I need to check which version of the shifter is in my STEs & only test those with the 1712 shifters (if I have any)
It's worth checking the 588 just to verify the graphics only fail on the 1712.
Ok...I'll get ready to download & transfer the files over to floppy...

Re: STE video chip

Posted: 26 Oct 2023 21:11
by chronicthehedgehog
Mine's a 1712, I'll give it a test. I do get the odd weird error.

Re: STE video chip

Posted: 26 Oct 2023 21:26
by chronicthehedgehog
IMG_20231026_211826.jpg
IMG_20231026_211821.jpg
Definitely a bit of a mess

EDIT:

Audio crackle as well

Re: STE video chip

Posted: 26 Oct 2023 21:29
by exxos
Just done a bit more testing.

The "default" behaviour is this:

default.PNG

BUT. Turning the pot to a total of 50R solves that problem. But not much after (still turning the pot) it results in the "wobble" issue.

wobble.PNG

Going to 130R total the image is fine again.


Interesting the 32MHz and 16MHz are now synced to the rising edges for it to work best. Though in my original tests with the 588 shifter, they were synced on the falling edges.

IMG_1573.JPG

But I have a inverter on my test board now. So I guess I need to switch that back out to see if the syncs then change again or not...

EDIT:

IMG_1574.JPG

So with the buffer back in , the pot is still on the extreme 130R point, but the image seems fine, but I can't adjust anymore for rising edges to be in sync.

So I think ill switch to the inverter & buffer combo as as I did more tests with that in place.

Really needs more tests to figure out what the hell is going on with all this but someone else can do that work ;)

Re: STE video chip

Posted: 26 Oct 2023 22:08
by exxos
chronicthehedgehog wrote: 26 Oct 2023 21:11 Mine's a 1712, I'll give it a test. I do get the odd weird error.
Like what exactly ?
chronicthehedgehog wrote: 26 Oct 2023 21:26 Definitely a bit of a mess
Looks like your not getting that expected diagonal lines but it does look more structured than mine :shrug:
Audio crackle as well

viewtopic.php?p=78844#p78844

Re: STE video chip

Posted: 27 Oct 2023 00:09
by chronicthehedgehog
exxos wrote: 26 Oct 2023 22:08 Like what exactly ?
Well it's probably just some general timing problem thinking about it, but about 50% of the times I load Lethal Xcess (the DBUG crack) the graphics are corrupt - quad vision like the bit planes are of sync is the only way I can describe it. It's strange that it's intermittent - especially after a cold boot

Re: STE video chip

Posted: 27 Oct 2023 00:29
by exxos
chronicthehedgehog wrote: 27 Oct 2023 00:09 Well it's probably just some general timing problem thinking about it, but about 50% of the times I load Lethal Xcess (the DBUG crack) the graphics are corrupt - quad vision like the bit planes are of sync is the only way I can describe it. It's strange that it's intermittent - especially after a cold boot
Yeah sounds like the same problem. @Steve had problems with the we were demo, but don't think it was documented exactly what was wrong.

I guess we need more test programs to diagnose the issues. But not sure what stuff generally breaks. Maybe right timing demos. I guess you could try the closure demo as that pushes everything..