PAL-to-NTSC issues on ECS Amigas?

[marcfrick2112]

Hey guys, well... I really should stay off of AtariAge, LOL! There's a little discussion about ST's, and a person mentioned this:

Just so we are clear, a PAL Amiga 500/1000/2000 can not generate a 60hz  true NTSC game environment because the entire chipset is a different  speed (7.14mhz vs 7.09mhz). If it is written for the DMA bus frequency  it will not work as smoothly due to the colour clock being different. It  all relates to the genlock native abilities of all Amigas.

So few NTSC only A500 games exist most people on forums go for PAL  machines with US power bricks etc to guarantee compatibility.

A1200/4000/CD32 has a truer NTSC mode via AGA                                          

Is this even REMOTELY true? No one on AA seems to believe me, but I have run hundreds of PAL games, and an app (ProTracker, LOL) on my NTSC Amiga 500.... In fact, on 3 different 500's. Granted, for some games, I needed 1MB chip enabled.... but some of the comments I read there, just don't make sense.... First off, there weren't many NTSC games... cuz NTSC is mainly used in USA and Japan...neither country had anywhere near the userbase of Europe...



I thought that Agnus generated the Master Color Clock on all Amiga's, regardless of the processor's clock speed...
All stemming from this:

One thing you will find that's pretty nice about the Atari ST series (in  comparison to Amiga's) is that they do a pretty good job of switching  between NTSC and PAL modes for most games. And there are 60to50Hz apps  to force PAL games to run correctly on NTSC machines.

Yea, I only have about 15 different programs for NTSC-to-PAL switching, not too mention WHDLoad's and MCP's tooltypes...
Man, even back in my ECS days, I had NO issues with either PAL or NTSC.

(Check my Theatre of Death thread)

So, great Amiga sages: What say you?
I really love to prove this wrong, and ... umm, rub it in the dude's face! :laughing:

[ChaosLord]

Just so we are clear, a PAL Amiga 500/1000/2000 can not generate a 60hz  true NTSC game environment because the entire chipset is a different  speed (7.14mhz vs 7.09mhz). If it is written for the DMA bus frequency  it will not work as smoothly due to the colour clock being different. It  all relates to the genlock native abilities of all Amigas.

There are no 7.14Mhz Amigas.  NTSC Amigas run at 7.15909 Mhz.  So I will call Shenanigans on the whole above comment. :roflmao:

So few NTSC only A500 games exist most people on forums go for PAL  machines with US power bricks etc to guarantee compatibility.

100% Bogus.  No wait, 10000% bogus.

The statement violates the causality principle.

Anything happening today cannot ever affect anything in the past.

99% of all A500s ever sold were sold before any internet forums existed.  

A1200/4000/CD32 has a truer NTSC mode via AGA                                          

What?  If you believe the first statement then this statement makes no sense.  If you do NOT believe the first statement then this statement no sense.

but I have run hundreds of PAL games, and an app (ProTracker, LOL) on my NTSC Amiga 500.... In fact, on 3 different 500's.

Me too.  We all have.  I have certainly done over 1000.

[/COLOR]

One thing you will find that's pretty nice about the Atari ST series (in  comparison to Amiga's) is that they do a pretty good job of switching  between NTSC and PAL modes for most games. And there are 60to50Hz apps  to force PAL games to run correctly on NTSC machines.

[/COLOR]100% Bogus.

On the Amiga any game that wants to open a PAL screen can just do it.
Any game that wants to open a NTSC screen can just do it.

For example I live in USA and ALL of my Amigas are NTSC Amigas.
Yet all the games I have written for Amiga are PAL games.  No need to run any PALboot util.  AmigaOS lets me open any screen I dam well please and I please to open a PAL screen.  You don't have a choice in the matter.  If you play one of my games you play in PAL no matter if you have a PAL or NTSC Amiga.

[marcfrick2112]

Thanks ChaosLord!

Yea, I really thought all that was bogus.....

Was afraid I was losing my mind...
Hmm, better post there, and then just stay away from the thread....

[marcfrick2112]

ChaosLord, I KNEW it!!

I was thinking... why would the Amiga's clock speed be 7.14, when the NTSC color subcarrier frequency is 7.15???

Hmm, a coincidence that both are the same frequency? LOL, nope...

[paul1981]

I try and stay out of Amiga/Atari wars.  It was 20 years ago LOL.  My advice is just enjoy your machine, whether it be Amiga, Commodore, Acorn, Amstrad, Spectrum, Apple or Atari (listed in no particular order of course). :roflmao:

[Matt_H]

As long as you have a 1MB Agnus or newer, you can switch between NTSC and PAL in software with zero compatability issues.

[Zac67]

For 100.00% hardware compatibility you'll need to swap the oscillator (required for genlocking, external video stuff, many TBCs, A2024, ...). This is also true for AGA since there are no timing differences between OCS, ECS and AGA.
However, for software compatibility this doesn't matter a bit (as long as you don't hear the music keys being off ~1%).

[marcfrick2112]

I try and stay out of Amiga/Atari wars.  It was 20 years ago LOL.  My advice is just enjoy your machine, whether it be Amiga, Commodore, Acorn, Amstrad, Spectrum, Apple or Atari (listed in no particular order of course). :roflmao:

Yea, Paul.. I think I will heed that advice now...It just bothered me, cuz as an Amiga owner, I didn't go to that thread to bash Atari ST's, in fact I posted that I would like to own one someday, and I would..

Zac67, thanks for that info, BTW..

[psxphill]

Just so we are clear, a PAL Amiga 500/1000/2000 can not generate a 60hz true NTSC game environment because the entire chipset is a different speed (7.14mhz vs 7.09mhz).

Quite a lot of computers can't generate a true NTSC (or PAL) signal, instead they produce something close enough that TV's could cope. The first VIC chip output 64 colour clocks per line instead of 65 for instance.
 
Amiga's can only switch between 50 & 60hz, they can't change between PAL and NTSC. The only thing that changes is the number of lines, which is good enough to make the refresh rate change but can still cause slight differences.
 
As everything is run from a single clock it probably makes no real difference in practise. I don't know what the tolerance is on the oscillator, but it might have drifted a little by now anyway.

[marcfrick2112]

Quite a lot of computers can't generate a true NTSC (or PAL) signal, instead they produce something close enough that TV's could cope. The first VIC chip output 64 colour clocks per line instead of 65 for instance.
 
Amiga's can only switch between 50 & 60hz, they can't change between PAL and NTSC. The only thing that changes is the number of lines, which is good enough to make the refresh rate change but can still cause slight differences.
 
As everything is run from a single clock it probably makes no real difference in practise. I don't know what the tolerance is on the oscillator, but it might have drifted a little by now anyway.

Thanks psxphill!
And yea, you are technically right... Exactly as the Sega Mega Drive is neither PAL or NTSC, but 50 or 60hz....(which may be why a good 85% of MD games can be gotten to work on an NTSC Genesis)

I believe it's Agnus that handles the master clock, right? *grr, now regret selling my A500 service manual... *


Really interesting thread, I am always learning new things here! :afro:

[psxphill]

I believe it's Agnus that handles the master clock, right? *grr, now regret selling my A500 service manual... *

page 2-5
 
http://www.1000bit.it/support/manuali/commodore/a500plus_sm/amiga500plus_sm.pdf
 
PAL & NTSC amigas have a slightly different 28mhz clock, which is divided by 4 to get the CPU clock speed. Everything runs off this & it isn't affected by changing the screen refresh rate.