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Discussing the Open Source FPGA Amiga Project
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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Mon Jul 11, 2011 4:54 pm 
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Joined: Tue Jul 27, 2010 12:59 am
Posts: 31
Location: France
@yacube does your monitor meet those 910 clocks per line ?

For info, I own a HP w2408h which support 50Hz but horizontal scrolling are ok, but not perfect :(


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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Mon Jul 11, 2011 7:00 pm 
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Joined: Mon Dec 01, 2008 9:58 pm
Posts: 1568
Location: .de
My Samsung SyncMaster 940BF allow the 910 clocks per line and scrolling appear without pixel crushing.
Still scrolling is not as clean as on a CRT screen.

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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Sat Dec 10, 2011 12:42 pm 
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Joined: Thu Oct 22, 2009 7:20 pm
Posts: 23
Anyone got experience with these small 8" LCDs like PL8006 (http://www.gadmei.com/en/product_show.aspx?id=102)? These things support 50Hz PAL but sometimes when connecting through VGA they refuse to display anything. I have no idea of this LCD though.

I've been looking for a 8" LCD that does PAL/NTSC (and VGA for minimig) and would have both AV & VGA inputs.. Any recommendations?


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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Sun Mar 04, 2012 9:45 am 
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Joined: Thu Sep 24, 2009 8:07 am
Posts: 36
Hi all,

I was glad to find this screen

Acer AL1521

It's small, 4:3, just the perfect thing I was looking for, but. When I plug the Minimig to it, I get the floating "Input not supported" box, ALTHOUGH the display is there. The image is good, I can see a crisp Workbench screen, it seems to work just fine, so why do I get the floating box???

Q1: I'm using the VGA port, could the DVI one possibly yield better results?

Q2: If not, Is there any way I could fool this device and get rid of the stoopid floating box?


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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Mon Mar 05, 2012 10:43 am 
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Joined: Mon Dec 01, 2008 9:58 pm
Posts: 1568
Location: .de
I guess this screen do no support 50Hz refresh rate.
Try Minimig in NTSC Mode (hold down F1 key after power-up or PGM RESET).

This is a common matter due to VGA standard is at least 56Hz of screen refresh rate.
In this case you are happy to still see any picture, most screen just stay blank.

DVI would be an option but only with real DVI hardware. By using an adapter to normal VGA, the analog way will be used and show same result.

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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Mon Mar 05, 2012 3:32 pm 
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Joined: Thu Sep 24, 2009 8:07 am
Posts: 36
Hey boing4000, thanks for your reply.

boing4000 wrote:
DVI would be an option but only with real DVI hardware.

If there is a DVI input plug at the back of the screen, would you call it "real DVI hardware"? If yes, I might hunt for an VGA-->DVI cable on the web... :)

EDIT: mmmmh... looks like I'll have trouble, 'cause I just realized the plug at the back of the screen is DVI-D, that is, it only accepts DVI plugs transporting digital data. And the VGA output of the Minimig is analog, right? :(


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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Mon Mar 05, 2012 5:54 pm 
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Joined: Mon Dec 01, 2008 9:58 pm
Posts: 1568
Location: .de
With "real DVI hardware" I actually mean DVI VGA card in PeeCee or the FPGAArcade Replay board etc.
Any adaption from analog VGA to DVI still is analog and will not gain advantage of the new signal / standard.

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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Mon Mar 05, 2012 7:40 pm 
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Joined: Thu Sep 24, 2009 8:07 am
Posts: 36
Just tried to switch to NTSC as you suggested boing4000, and... TA-DAAA, this works! The annoying floating box of "Input not supported" disappears! Thanks a lot! I never would have had the idea to test this!

This screen has the extreme stripped down version of an OSD for settings (image scaling limited to "clock", in other words "horizontal scale"), but all in all I get what I consider a pretty decent and centered image... for zero quid (screen was donated by a friend)!

The question remains about if this Acer AL1521 can be added to the 50Hz-friendly Monitors list, as NTSC actually is 59.94Hz.

Which brings this question to my mind: when will NTSC mode start to pose problems using the Minimig? Will certain games not run properly when this mode is selected, for instance?


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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Tue Mar 06, 2012 5:19 pm 
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Joined: Mon Dec 01, 2008 9:58 pm
Posts: 1568
Location: .de
NTSC mode in general is more incompatible to existing software (game/demo/cracktro).
Mostly coder act on scanline >200 to do a screen refresh, in this case the title will not work or show a freez image because there only is 200 scanline in NTSC.

Also many title will show speed differences. Mostly the speed is higher due to 60 screens per second but some title may show stocking.

This all is no Minimig issue, any Amiga(500) will act same way.
A real 50Hz PAL compatible screen would be best.

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 Post subject: Re: 50Hz Monitors for MiniMig
PostPosted: Tue Mar 06, 2012 6:35 pm 
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Joined: Wed May 27, 2009 10:51 pm
Posts: 479
i would say, as a summary for the Monitor-50Hz-thing here, it can be said, there are 3 possibilities to be sure, that it works without problems.

1) use a Samsung-Syncmaster, nearly all models from this type, seems to work with 50Hz

2) use a tube-television or tube-monitor (CRT-monitor) in 50Hz- or 100Hz-mode - (german factory METZ still has a very good tube-TV in the product-range. i have one of these and i am very satisfied with this one).

3) use a LCD-/LED-/Plasma-TV (they all can be used in NTSC- and PAL-countries, so they should work)

all other things seems to be risky and problems in scrolling could come when running PAL-games.

to be true, nothing is better then a good tube-TV or CRT-monitor for the Minimig. scrolling is absolutely perfect then, no tearing and no other problems.


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