ao486 Config for a Plain Old CRT TV

[thorr]

-if you feel like tweaking it all further, go ahead - I think I'll take a break and play some games finally Guybrush still looks a bit chunky but I think it's cuter this way. And 1.42 is pretty close to 1.33 already...

Here are two new modes for you to try. The original is on the bottom. Try the top one first. If it is still higher than 1.33 let me know and I can go further. If it is under 1.33, try the second one.

video_mode=1280,173,140,266,240,11,0,19,30086 ; slightly bigger borders on left and right compared to next line
;video_mode=1280,164,140,255,240,11,0,19,29760 ; slightly bigger borders on left and right compared to next line
;video_mode=1280,159,140,248,240,11,0,19,29568 ; For 320x200 games

[flynnsbit]

I did some more tweaking. I think this is my final version. It is extremely close to 4x3 aspect ratio and has the smallest border I could get and keep it at 59.94Hz and stay in sync.
[ao486]
; Set it to "Variable" in the ao486 core instead of 60Hz
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode=1280,152,140,261,240,15,0,19,30105 ; 4x3 for 320x200 games, 16.42kHz, 59.94Hz

Some TV's may have trouble syncing at 16.42kHz. My settings in the previous post might work if this post doesn't, as they are slightly less aggressive, or you can try reducing the 30105 number, but you will lower the 59.94Hz and might get tearing in games.

(Right click and Open Image in New Tab (in Firefox) and click on it to see the full resolution.)

For your reference and comparison, this is how I set up my CRT geometry with the SNES. This is the Grid at 256x224. I have minimal borders on the top and bottom. The upper right corner is slightly cut off and I need to open the CRT to try to fix that.

That looks really good!

[thorr]

Every new post and modeline gives me hopes and i try again, only to find the same problem:

Rolling vertical image. (Some modelines scroll slow and others do it fast)

I always get the vertical rolling screen when forcing modelines and turning off direct_video

direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode=1440,40,136,176,240,3,10,6,27000

I get ultra clear picture with that ini, but it scrolls up slowly. What parameters should i fine tune??

PS: Maybe i should note that i'm using an HDMI to VGA adapter. Then VGA to RGBs custom wiring. (Works a charm with other cores)

_javi_ Assuming my previous post did not help you with trying the new last number in the modeline that almost works for you, I am pretty sure I know exactly what the issue you are having is because I had the same problem. Read this post: viewtopic.php?p=13600#p13600 At the end, I had problems when the scaler was turned on, and it worked find with direct_video=1. The issue is occurring with the device(s) between the HDMI port and your TV. Are you using component inputs? Unfortunately, finding a perfectly working HDMI to component conversion product is next to impossible. I found one, but they don't make them anymore. There is a super easy solution though! Get an analog IO board for your MiSTer. I can almost guarantee it will work for you.

I just found this, and I have not tested this model, so it might just work. There are only 4 left: https://www.ebay.com/itm/274398685500

[_javi_]

Thanks for your attention to my problem, thorr and akeley.

Although i keep trying to improve my set up, tuning parameters, i cant afford to import new hardware. I'm from Argentina, so shipping and local customs taxes kill my pocket. And not to mention the dollar to argentine peso exchange rate..
My MiSTer is the poors-man version. I bought the bare nano10 from digikey, and the usb hub and hdmi to vga locally (and surprisingly they work perfect!).

For the video wiring part: I modded a Sony CRT TV (KV21-FE12A, BA-5 chassis, composite-in only) to accept R/G/B/S, adding a DB9 conector. The internal tv wirings are ok: 1k ohm on sync line, terminated R,G and B to ground, and all the recomended stuff. This setup worked fine with an Amiga500 and its original video cable. I tried a PS2 (RGB option in Settings, custom wiring) and it showed ok too. There i discovered that the horizontal centering of the image, coming from different video sources, was going to be an issue.

I use a homebrew DB9-DB15 cable with the HDMI/VGA adapter. It works fine with "all" the mister cores, and even with an N-Go board (ZX Next clone, DB15 connector, RGB mode). I dont know the internal chipset of the hdmi adapter.

Recently I found another Sony KV21-FE12A, on sale for 20usd. I'm getting it today. I guess i can use it as 2nd set, tuned with a proper Service Menu setting to center the screen as needed for the AO486 core (again with direct_video = 1).

It feels a bit like giving up on modelines testing, but its cheaper and faster than importing new gear.

[akeley]

@thorr: thanks mate, the latest one is now at 1.40 (vs 1.42 of the previous one). It's not a big difference, but it's already fine, don't worry about it. I might try tweaking them myself with that calculator one day at some future date.

My MiSTer is the poors-man version. I bought the bare nano10 from digikey, and the usb hub and hdmi to vga locally (and surprisingly they work perfect!).

Same here, only with 64 SDRAM. Why spend more money when it all works great for 99% of the stuff anyway?

If you modded the TV for RGB yourself you sure have some skills - nice! I don't think your problem here is down to modelines themselves, it's more likely to be either other settings (only other ones I can think could affect it are vsync/vscale ones) or some little thing with the cable or the TV itself. CRTs aren't all cut to size and might have slightly different tolerances for such tinkering. So maybe best would be trying to find a VGA CRT monitor for ao486, or indeed utilise that new Sony you're getting. Good luck!

[thorr]

I dont know the internal chipset of the hdmi adapter.

I think this HDMI to VGA adapter may be the issue. If you can crack it open, you can know for sure what the chipset is. From what I can tell both of these statements are true:
- Your TV works with everything you plug into it, except the MiSTer when direct_video=0
- Your TV never works when direct_video=1 no matter what modeline/resolution you try for any core

This tells me two things:
- There is likely something wrong with the scaler FPGA code that mucks up the video signal in some kind of way that makes the device doing the HDMI conversion do some clean up of the bad signal. I had the same issue when I was testing one of the bad component converters. I plugged in the direct_video=1 Menu timings into the scaler. The same timings worked with direct_video=1 but did not work with direct_video=0.
- The electronics in your TV are fine. The HDMI to VGA (or less likely, your ini settings) is the issue. I would verify the chipset of the adapter and buy another one with the AG6201 chipset.

Also I think a scrolling has to do with the sync signal. You could try adjusting the resistor value with a potentiometer and see if you can get the scrolling to stop (in your VGA to RGBS chain).

[thorr]

@thorr: thanks mate, the latest one is now at 1.40 (vs 1.42 of the previous one). It's not a big difference, but it's already fine, don't worry about it. I might try tweaking them myself with that calculator one day at some future date.

It's super easy to do. Plug the existing numbers into the calculator and click calculate (don't forget to put a decimal after the first two digits for the last number since it is MHz in the calculator). You should see 16.18kHz and 59.94Hz. Take the fourth H number and increase it by like 50 (based on what you told me of going from 1.42 to 1.4). Click calculate again. The 16.18 and 59.94 go down. Increase the MHz number and click calculate until it matches 16.18 and 59.94 again. Try it on your screen. It won't be centered but should be wider. Use the left or right buttons in the calculator to show how it affects the second and forth H number. One goes up, and the other goes down by 8, depending on left or right, but they are opposites. You can manually increase and decrease by any number instead of 8. This will not change the 16.18 and 59.94 when you click calculate if you did it right.

[thorr]

I have been playing with the settings some more and have some new timings.

For the menu, I had some shimmering with my previous settings. These ones work perfect for me and fit the screen edge to edge with no shimmering. I configured it for 60Hz.

[Menu]
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=1
video_mode=640,54,56,106,224,16,0,28,13764 ; Best 7-24-2021 - No Shimmering, No Border

For ao486, I have a new mode that works well with 320x240 (mode x) games (same as the menu timing above).
[ao486]
; Set it to "60Hz" in the ao486 core instead of "Variable" unless you are running Second Reality
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=1
video_mode=640,54,56,106,224,16,0,28,13764 ; Best for overall mode. Widescreen for 320x200, full-screen for DOS and Mode X games like Epic Pinball - use with vscale_mode=1

For 320x200 games, I created a 640x200 mode, but it isn't really any different than my previous 1280x240 mode. It pushes the frequency limits so it may not work for some people. I modified the 1280x240 mode to be 60Hz instead of 59.94.
video_mode=640,55,90,131,200,34,0,40,15058 ; 4x3 with small border for 320x200 games, 16.44kHz, 60Hz. Use with vscale_mode=3
or
video_mode=1280,132,140,281,240,15,0,19,30133 ; 4x3 with small border for 320x200 games, 16.44kHz, 60Hz. Use with vscale_mode=3 (see my previous 1280x240 timings if this doesn't work)

[FoxbatStargazer]

Every new post and modeline gives me hopes and i try again, only to find the same problem:

Rolling vertical image. (Some modelines scroll slow and others do it fast)

I always get the vertical rolling screen when forcing modelines and turning off direct_video

So just to confirm you may not be totally crazy.

I've been using several vga_scaler modelines in multiple cores, connected with VGA->component breakout with SoG on, on a Sony KV-32FS100 just fine. But I have yet to get one that will sync with a KV-27FS120, even though it works fine with every NTSC core analog output. You'd think these TVs would be practically the same, but apparently not.

[ski9k]

Heya all,

Thought it might be worth adding my 2 cents..... I tried about 30 different video mode settings before I found one that "95%" works for my SD tv (via component) thought i'd share my settings below in case it benefits anyone else.

[ao486]
video_mode=640,65,60,108,224,16,0,26,13919
vsync_adjust=1

* also make sure ao486 settings are set to 60hz refresh rate... NOT VARIABLE

- only issues ive encountered are slight "jittering" very occasionally in some games and the image is slightly too far to the left (maybe by about 5 pixels or so) with a slight black border to the right.

Hope this might be able to help someone out there if they are stuck like I was. Also if anyone could advise me what numbers to change to shift the image slightly right or at least stretch the image slightly to the right only by a few pixels I would greatly appreciate it!!

[siskavard]

I have pixel perfect games on my CRT TV. Dos text is not perfect because the resolution is too high, but games are great. Try these settings:
[ao486]
; Set it to "Variable" in the ao486 core instead of 60Hz
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode= 1280, 170, 140,244,240, 2, 0, 22, 29020 ; Best for ao486

I managed to get this to work on my Toshiba, however the image is cut off quite a bit. Still very cool to see it work on my TV nonetheless!

PXL-20211212-222819676.jpg (287.66 KiB) Viewed 20562 times

[thorr]

I have pixel perfect games on my CRT TV. Dos text is not perfect because the resolution is too high, but games are great. Try these settings:
[ao486]
; Set it to "Variable" in the ao486 core instead of 60Hz
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode= 1280, 170, 140,244,240, 2, 0, 22, 29020 ; Best for ao486

I managed to get this to work on my Toshiba, however the image is cut off quite a bit. Still very cool to see it work on my TV nonetheless!

Great! I posted some other timings you can try as well. If they are all cut off, you probably need to adjust your TV's geometry settings using the service menu. I used the SNES rom for setting up the geometry with the 224 vertical resolution option.

[FoxbatStargazer]

Resurrecting this thread because I stumbled on something that it seems may not have been considered: running DOS games in their native 70hz on 15khz! I was playing around with an SC1224 version 2 NTSC monitor, a JVC tube custom made for the Atari ST. It accepts both RGBHV and RGsB as long as you adapt to its proprietary 13-pin connector. Anyway this 15khz monitor was made primarily for 60hz and secondarily for 50hz, but I also found a modeline that made 70hz perfectly stable and great looking. The key was to just limit the resolution to 200p and to substantially increase the vertical blank so it had enough time to return to the top. Once done I could set ao486 menu refresh rate to variable (instead of 60hz) and vsync_adjust=1 or 2. I wondered whether something similar might work on PVMs at least? Anyway here's a line to try (with aspect ratio=full and hv integer, and low res=native)

Code: Select all

video_mode=720,84,64,128,200,3,9,12,15620

[thorr]

Just saw this, I will have to try it when I get back from vacation!

[mrchrister]

These settings are working on my PVM 2030. Make sure to set Aspect Ratio to Full Screen in Audio and Video Section of the core

Code: Select all

[ao486]
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode=1440,40,136,176,240,3,10,6,27000

[eobet]

These settings are working on my PVM 2030.

OMG, I think I've tried every config posted in these 5 pages, and literally yours (ie the last one) was what finally worked on my JVC TM-H150CG.

Thank you!

[mrchrister]

Great to hear.
You can play around with the values a little. In my case, changing it to:

Code: Select all

video_mode=1440,140,160,190,240,3,10,6,27000

made it fit even better (centered) on my setup.

The three values are Horizontal front porch (140), Sync (160) and back porch (190). which control the width and centering of the picture. Adjusting vertical sync is a lot trickier and you won't have as much room to play with as horizontally

[Barone]

Great to hear.
You can play around with the values a little. In my case, changing it to:

Code: Select all

video_mode=1440,140,160,190,240,3,10,6,27000

made it fit even better (centered) on my setup.

The three values are Horizontal front porch (140), Sync (160) and back porch (190). which control the width and centering of the picture. Adjusting vertical sync is a lot trickier and you won't have as much room to play with as horizontally

This post was very helpful to have my setup properly configured.
These are the settings that work best with my setup:

Code: Select all

[ao486]
; Set it to "60Hz" in the ao486 core instead of "Variable"
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode=1440,120,220,220,240,3,10,6,27000

It works perfectly with these two 15 kHz CRT TVs:
Philips 29PT6566 (chassis L04LAB SL6).
Philips 29PT5642 (and this specific unit is one of those which use the same tube that is used by some of the JVC I'Art 27¨) modded to use a later chassis (L04LAB SL7).

[eobet]

Just in case anyone else runs into this... I'm using PVMs, but want the old TV look, so I got a composite adapter and discovered that these video_modes which start with high numbers like 1440 etc produce weird colors via the adapter...

Orange colors using the "wrong" video mode on a composite adapter...

IMG_3696.jpg (399.43 KiB) Viewed 17565 times

So, I had to start over in the thread and try various configurations again, and this one seems to work out best on the composite adapter so far. The picture it produces on both my PVMs is too wide so it's a bit cut off (worse on the Sony than the JVC), but at least it's in color!

[thorr]

I just configured a new mode for my Panasonic TV in my arcade cabinet and it nearly fills the screen with a small border all the way around. It is basically perfect for this particular TV. The core MUST be set to Variable, not 60 Hz. It has a 66.01Hz sync rate, so this may not work on all TV's. Also, it only works with DOS text and 320x200 games. The resolution is 640x200 and the scaler can't downscale higher vertical resolutions.

[ao486]
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode=640,73,56,119,200,8,0,24,13600 ; 15.32KHz 66.01Hz - Core must be on Variable, and only works on 320x200 games

Here's a pic. You can see the gray around the edges to see that it nearly fills the screen. (Right Click, Open Image in New Tab)

GBnXeMh.jpeg (4.15 MiB) Viewed 4660 times

[FoxbatStargazer]

How can it be 66 hz with vsync_adjust=1? That should bump up the refresh to match the core output, which would be closer to 70 for 200/400p?

[thorr]

How can it be 66 hz with vsync_adjust=1? That should bump up the refresh to match the core output, which would be closer to 70 for 200/400p?

Good question! Maybe the vsync_adjust setting only gets used when you specify a resolution number and not a modeline for the video_mode.

Edit: Holy cr@p! It is working at 70.1Hz! I never noticed any tearing, and now I know why!

LbgF5bK.jpeg (4.46 MiB) Viewed 9548 times

[mist-rich]

For those with 15khz monitors, I finally got ao486 working perfectly on my PVM with this line (suggested earlier in the thread):
video_mode=640,6,56,66,224,14,8,18,1200

It looks absolutely perfect, like it's the proper native resolution (320x200). I also changed the setting to use the native aspect ratio so that the screen isn't stretched slightly vertically (fonts look a bit off when stretched).

Thank you, I am using same PVM and that helped me get an image. I still need to adjust sizing a little but its looking really nice HD screen will have to wait (not too bothered about it with this core) as I need direct_video for it to work but then crt will not output.

This has also made me realise exactly what we are doing and how adaptive the the Mister (and its users) are at getting around issues.
I mistakenly thought before that as the Mister has a VGA out , getting an ao486 image would be as easy as just inserting the cable. But a CRT is not a monitor as in 'PC monitor' (vga-vga), the signal is RGB Sounds obvious but I only realise that now.
What was the reason a VGA port was used on the Mister to output RGB? (this is not a criticism of the Mister in anyway, i'm really impressed by it) Why not keep that separate for VGA to VGA and then have another RGB output for consoles. Would it then be possible to have the best of all words and allow a HDMI monitor + CRT/PVM + VGA monitor all running at the same time (would that ever be possible?)?

[eobet]

Just in case anyone else runs into this... I'm using PVMs, but want the old TV look, so I got a composite adapter and discovered that these video_modes which start with high numbers like 1440 etc produce weird colors via the adapter...

IMG_3696.jpg

So, I had to start over in the thread and try various configurations again, and this one seems to work out best on the composite adapter so far. The picture it produces on both my PVMs is too wide so it's a bit cut off (worse on the Sony than the JVC), but at least it's in color!

Well, I've now switched to the more "officially supported" MiSTer FPGA YC Active Encoder Board from Misteraddons and now I'm back to having black and white again, even though I've set the vga_scaler to 0... anyone running AO486 with the newer composite support and having any luck?

[riblad_om]

Just in case anyone else runs into this... I'm using PVMs, but want the old TV look, so I got a composite adapter and discovered that these video_modes which start with high numbers like 1440 etc produce weird colors via the adapter...

IMG_3696.jpg

So, I had to start over in the thread and try various configurations again, and this one seems to work out best on the composite adapter so far. The picture it produces on both my PVMs is too wide so it's a bit cut off (worse on the Sony than the JVC), but at least it's in color!

Well, I've now switched to the more "officially supported" MiSTer FPGA YC Active Encoder Board from Misteraddons and now I'm back to having black and white again, even though I've set the vga_scaler to 0... anyone running AO486 with the newer composite support and having any luck?

I was just looking into this bc I was trying to get color to my composite-only set and I can't find any evidence that the core supports yc, unless I'm hopefully missing something. No YC ao486 core from Mike's YC downloader, either.

[eobet]

I was just looking into this bc I was trying to get color to my composite-only set and I can't find any evidence that the core supports yc, unless I'm hopefully missing something. No YC ao486 core from Mike's YC downloader, either.

It's looking pretty grim because both of the (so far) involved developers seem to be of the opinion that this should not work, and both have no interesting in getting it to work, but worse they also seem to completely ignore that it did in fact used to work (as evident by this thread).

Here's where I wish there would be a system where people could pool some money together and put a bounty up to fix this to get it working again.

[akeley]

"All-in-all ao486 is not for TV" - classic Sorg

Meanwhile:

https://postimg.cc/gallery/vBZnJ1w

[Antoine.WG]

"All-in-all ao486 is not for TV" - classic Sorg

He does have a point, though. By the time 486's came out, costs had come down considerably, PCs had become mainstream, dedicated VGA monitors had become the norm and very few people were using a TV as their main monitor or even attempting to.

[akeley]

"All-in-all ao486 is not for TV" - classic Sorg

He does have a point, though. By the time 486's came out, costs had come down considerably, PCs had become mainstream, dedicated VGA monitors had become the norm and very few people were using a TV as their main monitor or even attempting to.

Well, obviously, but it has nothing to do with what people would like to do in A.D. 2024. And as you can see above, it looks rather good.

[Bas]

Sorg definitely has a point. I was quite alive during the CGA/EGA/VGA/SVGA timeframe and spent part of that time in professional IT supporting PC's at businesses. None of these options ever had regular consumer TV's as mainstream options for a display. Nobody I knew at the time even considered it, except one case: schools that would wheel around TV/VCR/PC combinations on carts between classrooms. And those would plug in separate hardware dongles that would translate the VGA signal out into something the PAL TV could manage. It would look bad for productivity applications, most of the time, but it was awesome to play Doom on.