Well I did say it was dark - didn't realise how dark until I filmed it
Video driver thoughts
Re: Video driver thoughts
Who is awesome
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: Video driver thoughts
I lifted that highlighted pin which, and linked to small wire from it to the BLANKing line...
So when BLANK is high, it selects D-RGB mode, when BLANK is low it selects A-RGB mode...
Technically the A-RGB lines are floating, but at this time of night I did not care, and it works anyway so
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: Video driver thoughts
Brilliant so it was blanking relatedexxos wrote: ↑Thu Nov 29, 2018 9:58 pm
I lifted that highlighted pin which, and linked to small wire from it to the BLANKing line...
So when BLANK is high, it selects D-RGB mode, when BLANK is low it selects A-RGB mode...
Technically the A-RGB lines are floating, but at this time of night I did not care, and it works anyway so
Question now is to compare original circuit against new DAC circuit to see improvement.
Re: Video driver thoughts
Sadly it looks the same
Mostly I was trying to get rid of the vertical noise lines in the drag bar but they are still there... Only now they seem to be flickering a little bit...
I do have some 40R resistors in series with the RGB outputs with 47pF on them.. so its not like its noise there...
Gave myself permission to upload a high res shot to illustrate this...
The thing is, I don't think I saw this on the Falcon video.. and its the same chip now
BTW - the jumper does up the brightness a little, not a great deal...
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
- stephen_usher
- Posts: 5678
- Joined: Mon Nov 13, 2017 7:19 pm
- Location: Oxford, UK.
- Contact:
Re: Video driver thoughts
So, is this a similar issue to the “front porch”/“back porch” video generation issues that the early ZX81 ULAs had?
Basically in that case the ULA didn’t produce a “back porch” on the video signal so the TV/monitor circuitry couldn’t determine the base level of the signal. In the case of the ZX81 color TVs took the “white” level to be black and dimmed the display accordingly.
I guess that in this case the monitor could be taking a floating value as the black level, when the border is white. When it’s black then it emulates a back porch.
Basically in that case the ULA didn’t produce a “back porch” on the video signal so the TV/monitor circuitry couldn’t determine the base level of the signal. In the case of the ZX81 color TVs took the “white” level to be black and dimmed the display accordingly.
I guess that in this case the monitor could be taking a floating value as the black level, when the border is white. When it’s black then it emulates a back porch.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
Re: Video driver thoughts
Well done guys. Looking better and better.
You'll get there with the quality thing Exxos, just take a bit of tweaking is all.
Will lift the pin tomorrow and catch up yet again, lol.
Still didn't fix the floppy drive problem, too busy with Fallout 76.
You'll get there with the quality thing Exxos, just take a bit of tweaking is all.
Will lift the pin tomorrow and catch up yet again, lol.
Still didn't fix the floppy drive problem, too busy with Fallout 76.
If it ain't broke, test it to Destruction.
- stephen_usher
- Posts: 5678
- Joined: Mon Nov 13, 2017 7:19 pm
- Location: Oxford, UK.
- Contact:
Re: Video driver thoughts
It looks like your display is doing a great deal of “sharpening”. Lots of nasty halos!exxos wrote: ↑Thu Nov 29, 2018 10:06 pmSadly it looks the same
Mostly I was trying to get rid of the vertical noise lines in the drag bar but they are still there... Only now they seem to be flickering a little bit...
I do have some 40R resistors in series with the RGB outputs with 47pF on them.. so its not like its noise there...
Gave myself permission to upload a high res shot to illustrate this...
IMG_3626.JPG
The thing is, I don't think I saw this on the Falcon video.. and its the same chip now
BTW - the jumper does up the brightness a little, not a great deal...
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.