Spec core with ZXMMC+

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Re: Spec core with ZXMMC+

Postby Newsdee » Tue Jun 07, 2016 6:20 am

I've written about it in the wiki. Let me know if you have any questions:
https://github.com/mist-devel/mist-board/wiki/Displays

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 8:33 am

I recommend SCART->HDMI Scaler LKV362A. I'm using this scaler. Works with any TV modes (PAL/NTSC) and can output HDMI 720p/1080p 50Hz/60Hz with frame rate conversion if needed.
For example this lot on Aliexpress: http://www.aliexpress.com/item/Up-Scale ... 4cd22735ec
There are other sellers with this scaler.
You will need to make VGA->SCART cable (see MiST Wiki).

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 8:41 am

Newsdee wrote:I've written about it in the wiki. Let me know if you have any questions:
https://github.com/mist-devel/mist-board/wiki/Displays

Wiki has outdated info. XRGB-mini may be good but extremely expensive. I have Gonbes 8220 and could make it work stably. I don't recommend it at all. Also i have cheap MS9282 converter. It's not scaler at all. It just convert video into HDMI without any modifications and require VGA horizontal frequency (i.e. require scandoubler). I don't recommend it as well.

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Re: Spec core with ZXMMC+

Postby Newsdee » Tue Jun 07, 2016 8:49 am

Does this upscaler work with 31khz via SCART as well? Asking because not all cores supports disabling the scandoubler.

I think I wrote the MS9282 doesn't upscale. I'll double check and revise if that's not clear.

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 11:24 am

LKV362A Supports only TV (15KHz) resolutions on SCART input. But supports VGA converted to HDMI video on HDMI input.
Actually my setup is like this:
VGA splitter -> (1) SCART input of LKV362A and (2) MS9282 which output to HDMI input of LKV362A.
Then if i want to test scandoubler then i simply press "input switch" on LKV362A.
This setup is too bulky, but since i develop the cores i need to test both modes.

Unfortunately, there are no universal converters/scalers supporting 31KHz and 15KHz at the same time on the same input. All VGA converters expect 31khz only. Well, at least i didn't find such converters.

VGA output used on MiST is very very big headache actually. Could it be HDMI - there wouldn't be a problem to output 31khz (HDTV) and 15khz (SDTV) to the same TV without any scalers because both modes are standard for HDMI and supported by all HDTV-ready TVs.

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Re: Spec core with ZXMMC+

Postby Newsdee » Tue Jun 07, 2016 12:21 pm

Sorgelig wrote:Unfortunately, there are no universal converters/scalers supporting 31KHz and 15KHz at the same time on the same input.


Yes there is... the XRGB works fine by feeding a 31khz signal through SCART. I use a VGA->SCART converter to connect it. I know its expensive but it handled everything I threw at it... so its reputation is well deserved IMHO.

From reading comments on other boards it seems HDMI is no panacea either, some people forced the clocks of the cores to change slightly to get them to match HDMI, but I suppose that can cause compatibility issues.

I suppose one solution would be to pick a very common (and cheap) HDMI conversion chip, then find a VGA signal frequency that works well with it? Wouldn't upscale but I expect modern TVs would do a better job at upscaling a digital HDMI signal than VGA analog.

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 2:07 pm

I would exclude XRGB from discussion. 320 bucks... c'mon it's not serious to talk about it. Doesn't matter how it's good. It just pure marketing price because actual bone price is the same as Gonbes. It's just very poor firmware used in Gonbes made potential universal upscaler into thrash. (Honestly speaking LKV362A also could accept SCART 31KHz if vendor would like to).

For scandoubler-only output MS9282 should be ok, although it can have very big range of qualities due to very cheap noname manufacturers.
But from my point of view, the main signal should be TV 15KHz because all retro computers made exactly for this signal (well, except Amiga with productivity modes - but it hardly can be counted because it's only for Workbench apps).
Scandoubler is too unnatural for me. It produces signal never used as standard neither in past nor today. Just by some coincidence in universal circuits this strange signal is supported in some monitors.

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Re: Spec core with ZXMMC+

Postby ericgus » Tue Jun 07, 2016 3:13 pm

What if you dont have a SCART cable .. those are pretty rare in the USA.. no devices support SCART here ..

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Re: Spec core with ZXMMC+

Postby Newsdee » Tue Jun 07, 2016 3:50 pm

The XRGB uses an FPGA, it's quite different than the Gombes (perhaps you meant the chips cost the same, but you have to factor in their propietary core to make it work).

I get it's not for everybody but it has a strong following in the arcade world and those that own multiple systems. I certainly don't expect anybody to go buy one for the MIST, but those that have one already would be interested in knowing the MIST works very well with it (I was in that situation and I did wonder).

In principle, how difficult (and cheap/expensive) would it be to make a custom board to upscale the MIST signal? If it could be made around the price of the Gombes it could be sold as a MIST add-on...

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Re: Spec core with ZXMMC+

Postby duhproject » Tue Jun 07, 2016 5:25 pm

ericgus wrote:What if you dont have a SCART cable .. those are pretty rare in the USA.. no devices support SCART here ..


I have a nifty SCART to HDMI converter that was cheap and has performed minor miracles with my Amiga, ZX Spectrum, and VIC20. Might rig something up with the MiST to see what it can do.

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 5:28 pm

I don't know if special DAC chips are required to input VGA into FPGA, or FPGA can handle DAC by itself. If second, then price for such converter will cost of FPGA + SRAM (512k should be fine) chips with PCB and assembling cost.
Actually, i was thinking of simple piggy-back addon on top of VGA resistors. with simple HDMI connector. Just like some jailbrake clip-on chips.
But i'm not sure if VGA output resistors will interfere HDMI signal or not. So, if it possible then it will be just a matter of core where can add HDMI coder module.

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 5:29 pm

ericgus wrote:What if you dont have a SCART cable .. those are pretty rare in the USA.. no devices support SCART here ..

Aliexpress will help you with cables :)

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 5:30 pm

duhproject wrote:I have a nifty SCART to HDMI converter that was cheap and has performed minor miracles with my Amiga, ZX Spectrum, and VIC20. Might rig something up with the MiST to see what it can do.

Tell the name of this converter.

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Re: Spec core with ZXMMC+

Postby ericgus » Tue Jun 07, 2016 7:05 pm

Sorgelig wrote:
ericgus wrote:What if you dont have a SCART cable .. those are pretty rare in the USA.. no devices support SCART here ..

Aliexpress will help you with cables :)


True but then what? .. There are no displays over here that have SCART ports.. cable wont help much with nothing to connect it to.

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Re: Spec core with ZXMMC+

Postby Sorgelig » Tue Jun 07, 2016 7:34 pm

ericgus wrote:True but then what? .. There are no displays over here that have SCART ports.. cable wont help much with nothing to connect it to.

You can connect LKV362A(or similar) scaler.
There are no devices with SCART here as well, btw ;)

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Re: Spec core with ZXMMC+

Postby ericgus » Tue Jun 07, 2016 7:44 pm

Sorgelig wrote:
ericgus wrote:True but then what? .. There are no displays over here that have SCART ports.. cable wont help much with nothing to connect it to.

You can connect LKV362A(or similar) scaler.
There are no devices with SCART here as well, btw ;)


got a picture of how thats wired..? im just trying to envision how that would work.. maybe I am missing something,,

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Re: Spec core with ZXMMC+

Postby duhproject » Tue Jun 07, 2016 8:57 pm

Sorgelig wrote:
duhproject wrote:I have a nifty SCART to HDMI converter that was cheap and has performed minor miracles with my Amiga, ZX Spectrum, and VIC20. Might rig something up with the MiST to see what it can do.

Tell the name of this converter.


It simply says HD Video Converter -- SCART/HDMI to HDMI 720P/1080P. There are no brand names on it. Here's a link:

http://www.ebay.com/itm/Scart-HDMI-to-H ... SwBahVUcth

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Re: Spec core with ZXMMC+

Postby ericgus » Tue Jun 07, 2016 9:45 pm

duhproject wrote:
Sorgelig wrote:
duhproject wrote:I have a nifty SCART to HDMI converter that was cheap and has performed minor miracles with my Amiga, ZX Spectrum, and VIC20. Might rig something up with the MiST to see what it can do.

Tell the name of this converter.


It simply says HD Video Converter -- SCART/HDMI to HDMI 720P/1080P. There are no brand names on it. Here's a link:

http://www.ebay.com/itm/Scart-HDMI-to-H ... SwBahVUcth


so do you go VGA-SCART from the MiST .. then into this box .. then out to HDMI? so you need a VGA to SCART cable then??

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Re: Spec core with ZXMMC+

Postby Sorgelig » Wed Jun 08, 2016 7:29 am

ericgus wrote:got a picture of how thats wired..? im just trying to envision how that would work.. maybe I am missing something,,

It's pretty stright and simple: MiST -> VGA-SCART cable (see MiST Wiki) -> LKV362A -> HDMI cable -> TV (or whatever HDMI display).
Need to mention that audio also will be mixed by LKV362A into HDMI signal.
I don't think you can find SCART cable which will be compatible with MiST, so most likely you will need to re-solder it to match MiST output. May be store where you bought the MiST, has SCART cable as well.

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Re: Spec core with ZXMMC+

Postby ericgus » Wed Jun 08, 2016 7:32 am

Sorgelig wrote:
ericgus wrote:got a picture of how thats wired..? im just trying to envision how that would work.. maybe I am missing something,,

It's pretty stright and simple: MiST -> VGA-SCART cable (see MiST Wiki) -> LKV362A -> HDMI cable -> TV (or whatever HDMI display).
Need to mention that audio also will be mixed by LKV362A into HDMI signal.
I don't think you can find SCART cable which will be compatible with MiST, so most likely you will need to re-solder it to match MiST output. May be store where you bought the MiST, has SCART cable as well.



Turns out Lothrak sells one .. (indeed where I got it from)

http://lotharek.pl/product.php?pid=168

ok thanks .. this helps .. looks like I need to invest in a few items..

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Re: Spec core with ZXMMC+

Postby Sorgelig » Wed Jun 08, 2016 7:33 am

duhproject wrote:It simply says HD Video Converter -- SCART/HDMI to HDMI 720P/1080P. There are no brand names on it. Here's a link:

http://www.ebay.com/itm/Scart-HDMI-to-H ... SwBahVUcth


Looks like the same to LKV362A but in different case. And extra PAL/NTSC button. In LKV362A it uses one button to switch between PAL/NTSC abd 720p/1080p: 720P50/720P60/1080P50/1080P60.
Did you try to feed scandoubler (31KHz) into SCART of this converter?

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Re: Spec core with ZXMMC+

Postby Sorgelig » Wed Jun 08, 2016 7:35 am

ericgus wrote:Turns out Lothrak sells one .. (indeed where I got it from)

http://lotharek.pl/product.php?pid=168

ok thanks .. this helps .. looks like I need to invest in a few items..

Quite expensive, but at least there is an option to get the cable without an extra work.

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Re: Spec core with ZXMMC+

Postby Sorgelig » Wed Jun 08, 2016 2:50 pm

OSSC looks like ultimate scaler:
http://junkerhq.net/xrgb/index.php/OSSC

Opensource and FPGA. Unfortunately, i cannot find pre-assembled boards.

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Re: Spec core with ZXMMC+

Postby duhproject » Wed Jun 08, 2016 3:37 pm

ericgus wrote:
so do you go VGA-SCART from the MiST .. then into this box .. then out to HDMI? so you need a VGA to SCART cable then??


I haven't done this yet, btu I would assume I will need a VGA to SCART setup.

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Re: Spec core with ZXMMC+

Postby duhproject » Wed Jun 08, 2016 3:38 pm

Sorgelig wrote:
duhproject wrote:It simply says HD Video Converter -- SCART/HDMI to HDMI 720P/1080P. There are no brand names on it. Here's a link:

http://www.ebay.com/itm/Scart-HDMI-to-H ... SwBahVUcth


Looks like the same to LKV362A but in different case. And extra PAL/NTSC button. In LKV362A it uses one button to switch between PAL/NTSC abd 720p/1080p: 720P50/720P60/1080P50/1080P60.
Did you try to feed scandoubler (31KHz) into SCART of this converter?


I haven't tried yet -- I'll give it a go when I can.


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