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Author Topic: NTSC/PAL combo A500 -- How did they do it?  (Read 3735 times)

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Offline Kronos

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Re: NTSC/PAL combo A500 -- How did they do it?
« on: October 17, 2011, 08:23:46 AM »
1.3 didn't have a option for switching NTSC/PAL, but since it's really just one bit it's not too hard to do.

Back in the days a typed in a short assembler-listing found in a magazine and put the resulting exe on a bootable floppy.

After booting the A500 would auto-reset (you now had to remove the floppy pretty fast please) and returned in NTSC mode. Pretty nice for WB (couldn't stand 50Hz) or games that didn't use the extra screen real estate offered by PAL.

Note, a PAL-Amiga switched to NTSC is still producing PAL only at 60Hz instead of 50Hz and vice versa.
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Offline Kronos

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Re: NTSC/PAL combo A500 -- How did they do it?
« Reply #1 on: October 18, 2011, 09:41:06 AM »
Quote from: Zac67;663934
They don't. For exact compatibility (genlock, A2024 monitor) you need to swap the oscillator - usually this isn't necessary though.


A2024 works just fine on a PAL Amiga, no matter wether running 50 or 60 Hz
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Re: NTSC/PAL combo A500 -- How did they do it?
« Reply #2 on: October 18, 2011, 09:10:14 PM »
@Zac67

??

When you replaced the NTSC-Agnus with a PAL one, you really done nothing different than switching an ECS-Agnus between PAL&NTSC.

Changing the oscillator made that Amiga a "pure" PAL one (including pixelclock).

My 2024 worked both with Agnus set to PAL and NTSC (with a PAL-pixelcock I assume). The timing difference between NTSC and PAL is so minimal that I would suspect something different.
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1. Make an announcment.
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4. Wait for someone else to do it.
5. Start working on it while giving out hillarious progress-reports.
6. Deny that you have ever announced it
7. Blame someone else
 
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