NTSC MiniMig

[Firedawg]

Thanks Alex,  I'm in the process of soldering everything, holding out on the crystals.  I have all the past dialog on the NTSC Minimig subject, which you started, again thanks.  I need to purchase the crystals for the change to NTSC.  When I get to the programming part, that will slow me down some and I will rely on what has been discussed.  Can I use you as a resource when I get to the programming stuff?  I would appreciate it.

Mike
"Firedawg"

[Akira]

Hans_ wrote:
How did the later Amigas support both NTSC & PAL?

I am not sure. I know that it was more than changing the video timing, when you select 60Hz (NTSC) the Amiga bus clock changes too.

As far as I understood, the clock rate would chage, and NOT the video NORM. This was very noticeable: in my PAL Amigas.
when I switched to "ntsc", my NTSC TV would still not catch onto the colors of it or anything. The screen was at 60Hz but the color system remained that of PAL.

On my NTSC A1200, when I switch to "PAL", the machine switches to 50Hz but retains the color system of NTSC, thus giving the strange "PAL-M" combo (50hz with NTSC color system)

So none of the machines wouyld natively support the REAL output of the other. PAL machines switched to NTSC were not giving out really NTSC (more like 60Hz PAL), and NTSC machines were not giving out PAL (only PAL-M or NTSC @ 50 Hz)


I think you are overlooking over what really makes an NTSC or PAAL signal what it is. Not only the clock rate is what defines them, also their color system.

An Amiga that did FULL NTSC -and- FULL PAL would be a godsend!

[Akira]

Crom00 wrote:
For anyone that doesn't have a commodore or 3rd party montior with a 31/15.17 klhz and 50 hz capability you will have a hard time getting Minimig to work.

Most all modern LCD/VGA displays (even multisystem units) display VGA signals starting at 60hz.

The problem is the scan rate and not the sync rate.
LCD TVs that are displaying PAL should do so at a sync of 50Hz (you can't change that  standard) but the problem is that most of these only accept SCAN RATES starting at 30Khz. Not even DoublePAL or DoubleNTSC modes, that go at 28Khz, work on monitors of today. You connected it through RGB?

[alexh]

Not sure I fully understand the subtleties but I dont think MiniMig (or any Amiga) suffers from "colour system" problems when not using RGB. I thought it only affected COMPOSITE or RF? Like I said I don't fully understand.

The problem is the scan rate and not the sync rate.

Nope the problem is the sync rate.

LCD TVs that are displaying PAL should do so at a sync of 50Hz

Yeah, but most LCD MONITORS have a minimum sync of 56Hz.

most of these only accept SCAN RATES starting at 30Khz. Not even DoublePAL or DoubleNTSC modes, that go at 28Khz, work on monitors of today. You connected it through RGB?

MiniMig has an "AMBER" scandoubler and produces 31KHz output.

[jj]

Sorry I can understand what you are trying to achieve cause of the problems with monitors supporting 50hz.  But really do not think NSTC is the way to go.  Its a crap tv standrard.  I dont even know how possible this, but wouldnt PAL-60 be a much better option ?

[Krusher]

PAL-60 could be an option but is not a solution for programs that rely on scanline timings (PAL has 625 lines, NTSC 525)

[alexh]

JJ wrote:
But really do not think NSTC is the way to go.  Its a crap tv standard.  I don't even know how possible this, but wouldn't PAL-60 be a much better option ?

PAL-60 would require ECS AGNUS support which is a big job. Support for 60Hz is only one of lots of the changes between OCS and ECS ANGUS'. We're talking 100's of lines of code and many weeks of test. Going forward, that is the way to go, but not now.

Switching MiniMig from "PAL" to "NTSC" is perhaps 4-5 lines changed in Agnus.v (maybe more in the AMBER) and a different crystal.

MiniMig only outputs RGB, and it's scandoubled so it's not really NTSC (or PAL), is it?

[jj]

Fiar enough, was just wondering is all  :-D

[amigadave]

alexh wrote:

Switching MiniMig from "PAL" to "NTSC" is perhaps 4-5 lines changed in Agnus.v (maybe more in the AMBER) and a different crystal.

MiniMig only outputs RGB, and it's scandoubled so it's not really NTSC (or PAL), is it?

Has anyone successfully converted the Minimig to NTSC?  I have seen some suggestions of what changes might need to be made, but have not seen any report that anyone has done so and made it work.

There must be at least a few Minimig enthusiasts here in the USA, or in other countries where NTSC is the standard instead of PAL. (please, let's not get into any argument about which standard is better, that has been discussed at great length in the past and does not need repeating)