Sophia rev.C - DVI board

[TheMontezuma]

How did you mount/fix the dvi connectorboard on the inside?

 

I have desoldered the RF modulator to make space for the DVI connector.

And i screwed it directly to the enclosure. The hole was a manual work with file tools.

[jowi]

I'm at a loss why the Sophia DVI board with 1280x960 is giving me so much problems? Any suggestions? Would 1280x1024 or 1600x900 a better choice?

Or would it be best (if possible...) to have the board output an actual standard HDTV resolution, 720p50 (1280x720@50hz)?

Edited November 2, 2018 by jowi

[Simius]

I don't think so. The problem lies in the flexibility of the monitor. If don't work with 1280x960 then probably will don't work with any other Sophia's resolution. If the monitor strictly requires a compliance with the VESA standard, it can make a troubles with the Sophia board. The timings possible to obtain from the 8-bit Atari without a frame buffering are only roughly compatible with the VESA standard.

[jowi]

I'm not sure what the Acer monitor expects, but according to the Pioneer Kuro (the Kuro is truly a hi-end television...) manual the Pioneer Kuro should support 1280x960 with Hf:60khz and Vf:60hz... so by the looks of it 1280x960@50Hz is not supported according to the manual, while 720p50 is (1280x720 Hf 37.5khz, Vf 50hz).

 

 

Same issues with the JVX-X7500 4K projector, it sees an incoming signal of 1280x960 (Hf 62,2Khz, Vf 60Hz) but it can't do anything with it. See picture... how cool would this be, playing Atari games on this 120" screen

I would love to figure out some way to get the Sophia board outputting some resolution that can be reproduced by any 'normal' HDTV, not only by some exotic pc monitor that should be matched to the board.

 

Is there anything we can try? i wouldn't mind buying another board if you could e.g. program 720p50 in it, as close as possible to the VESA standard, if that is possible?

Or is there anything else we can test or try?

 

*edit* just read your pm, 720p50 can not be done... too bad.

Edited November 2, 2018 by jowi

[jowi]

Now this is an interesting observation; the DVI board should output 1280x960 (the blue editor with the upper and lower black bar, clearly visible, but sometimes when you turn it on, it also shows a lot more signal... this even looks like it is outputting 1920x??? Or is this just some memory artifact that happens when you reboot the atari too fast? (The yellow is not edited; it is the actual signal)

 

I'm asking this because someone over at AVSForum said that because the 1280x960 is not centered but placed at the top-left, the signal coming from the Atari might even be 1920x1080, which should not be possible. Strange effect nevertheless...

Edited November 2, 2018 by jowi

[jowi]

double post... please delete...

Edited November 2, 2018 by jowi

[bfollowell]

I tried to PM for pricing and availability but I get this message:

 

The member Simius cannot receive any new messages

 

I'm assuming his in-box is overflowing because of the apparent popularity of this board! I'll keep trying.

Edited November 6, 2018 by bfollowell

[jowi]

On Simius' advice i got me an HP LP2465 (2nd hand) and tried the Sophia board... perfection would be nice if the signal was 'easier' so most HDTV's or pc monitors would display it without issues. My goal is still to play games on my Pioneer Kuro HDTV or on the 120" 4K projector... but this will do for now.

 

 

 

 

 

[damosan]

Dumb question - where do you buy one of these? Thanks.

[jowi]

Send Simius a private message.

[_The Doctor__]

being restricted to even less monitor choices is just not a good thing in my mind.....

[jowi]

I agree... i'm looking for a solution, maybe a cheap aliexpress hdmi-hdmi 2K/4K scaler that accepts the input and can re-scale it to a standard 720p/1080p. That would solve it. Maybe scalers are less picky about the incoming signal then monitors and tv's.

I'm not sure what Simius can do with timings, h/v porch settings etc. to make the signals more compatible.

Edited November 15, 2018 by jowi

[Simius]

I cant do the one most significant thing - to change the PAL vertical frequency. It will be always 49.86Hz.

[foft]

Could change it to 50Hz. Need to change the crystal into GTIA to one 50/49.86 * current one :-)

[Simius]

Difference between 50 and 49,86Hz is not a problem because it is less than 0,5%. Problem is that the monitors usually have a range from 56Hz up.

[jowi]

My Pioneer tv does 23.976, 24, 25, 29.97, 30, 50, 59.94 and 60hz... and it does NOT show Sophia's output correctly... neither 1280x960 nor 1280x1024.

I really think it's a porch/timing thing.

Edited November 15, 2018 by jowi

[+slx]

Difference between 50 and 49,86Hz is not a problem because it is less than 0,5%. Problem is that the monitors usually have a range from 56Hz up.

 

Sorry, a bit OT, but where is the 49,86Hz actually documented? Whenever I search the web for PAL frequencies I find 50Hz. Is that an Atari peculiarity or the actual PAL standard?

[Simius]

I wrote about of PC monitors, not TVs. Monitors accept a wide range of the horizontal/vertical frequencies, pixel frequencies and graphics modes. TVs not. Video formats for the TVs are defined with the pixel clock accuracy of +/-0.5%. I examined recently one of my TVs (SONY KDL-47W805) with the picture generated artificially by the FPGA clocked with the high stability DDS generator. Frequency shift by 2% resulted in the lack of an image.

4K UHD TVs seems to be more flexible, but to what extent and whether all - still don't know.

[Simius]

 

Sorry, a bit OT, but where is the 49,86Hz actually documented? Whenever I search the web for PAL frequencies I find 50Hz. Is that an Atari peculiarity or the actual PAL standard?

 

It is very simple. Main clock of PAL Atari is 3.546894MHz. Picture generated by ANTIC has a 228 cycles/line and 312 lines/frame. 3546894/228/312 is 49,86Hz

Edited November 16, 2018 by Simius

[jowi]

I wrote about of PC monitors, not TVs. Monitors accept a wide range of the horizontal/vertical frequencies, pixel frequencies and graphics modes. TVs not. Video formats for the TVs are defined with the pixel clock accuracy of +/-0.5%. I examined recently one of my TVs (SONY KDL-47W805) with the picture generated artificially by the FPGA clocked with the high stability DDS generator. Frequency shift by 2% resulted in the lack of an image.

4K UHD TVs seems to be more flexible, but to what extent and whether all - still don't know.

Thing is, there IS an image, it is just shifted to the left-upper corner of a 1920x1080 image (both with my tv as my monitor)... so the picture *can* be displayed, just not in the right way, hence my suspicion something is wrong with h/v front/backporches.

[+slx]

 

It is very simple. Main clock of PAL Atari is 3.546894MHz. Picture generated by ANTIC has a 228 cycles/line and 312 lines/frame. 3546894/228/312 is 49,86Hz

Thanks, this is very much appreciated!

[Simius]

Thing is, there IS an image, it is just shifted to the left-upper corner of a 1920x1080 image (both with my tv as my monitor)... so the picture *can* be displayed, just not in the right way, hence my suspicion something is wrong with h/v front/backporches.

 

You're wrong. This is not an analog signal, where a sync pulses decide about centering the picture. The borders of an digital image are determined by a separate DE (DataEnable) signal. On my monitors I can even remove the h/v sync pulses at all and the picture is quite normal. Your TV recognizes the image parameters incorrectly and a result is as is.

It is like an human identity recognize - it can be recognize by the face or can be recognize by the clothes. Your TV recognize by the clothes.

Edited November 16, 2018 by Simius

[jowi]

 

You're wrong. This is not an analog signal, where a sync pulses decide about centering the picture.

 

Here's a bit on scaling a digital (DVI) output from a Lumagen Vision HDP scaler:

 

So even in the digital domain, there is an understanding of front and back porches, defined as pixels in this case.

 

You even showed me the exact timings of the signal:

Main parameters of the Sophia's DVI 1280x960 resolution on the PAL system are:

Horizontal pixels = 1280
Vertical pixels = 960
Horizontal frequency = 62.2kHz
Vertical frequency = 49.86Hz
Pixel clock = 113.5MHz
Horizontal polarity = negative
Vertical polarity = negative
Scan type = noninterlaced
Horizontal total time = 1824 pixels
Horizontal address time = 1280 pixels
Horizontal front porch = 112 pixels
Horizontal sync time = 160 pixels
Horizontal back porch = 272 pixels
 
Vertical total time = 1248 lines
Vertical address time = 960 lines
Vertical front porch = 3 lines
Vertical sync time = 3 lines
Vertical back porch = 282 lines

The fact that most (!) pc monitors & tv's do not accept the Sophia board (and even the HDFury Vertex doesn't understand it...) tells me there is some sort of compatibility issue with the timings of signal itself.

 

To be clear, this is not an attack or rant or anything i just want to make this work...

Edited November 16, 2018 by jowi

[jowi]

Potatos potatoes.

Edited November 16, 2018 by jowi

[Simius]

I didn't said that there is no such parameters like the front and back porches in the DVI signal. I said that these parameters don't affect on the position of an image. Your TV, instead of calculating the actual number of pixels/line and lines/frame and centering the image accordingly, treats the picture from the Sophia as 1920x1080. Why? l think when it gets confused, it kind of runs home to mama. Begins to draw an image from the upper left corner. Without any scaling, without any centering. Front and back porches have nothing to do with it.

Sophia DVI board works good with the most of PC monitors on the NTSC systems and with some PC monitors on the PAL systems. For the reason given above. I didn't promise that the Sophia will work with any TV.

Edited November 16, 2018 by Simius