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Old 25 October 2019, 00:36   #1
slaapliedje
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WHDLoad and PAL vs NTSC?

I have two A4000s now, and it is great that it is the one Amiga that has a jumper for PAL/NTSC (pretty sure all the others you have to either use early startup or a boot loader that switches). So my first A4000 I just stuck on PAL, so that all the games would work. My secondary one I left on NTSC as I believe the Video Toaster requires it.


But that means if I want to play a game (in this case Hudson Hawk), I have to make sure to go into Early Startup and put the system into PAL mode, just switching to a PAL resolution isn't good enough.


So my question is, can't this be done directly with patching the whdload slaves? Seems to me the games mostly require the early boot because they ignire whatever the workbench screen is (in fact it creates its own on top, doesn't it?) Is there just an option I am missing? Any database out there of games that only work in PAL?
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Old 25 October 2019, 02:38   #2
Damion
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The "PAL" and "NTSC" tooltypes for WHDLoad appear to be what you are looking for (can be set global, or per individual slave).
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Old 29 October 2019, 00:32   #3
AmigaHope
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Quote:
Originally Posted by slaapliedje View Post
I have two A4000s now, and it is great that it is the one Amiga that has a jumper for PAL/NTSC (pretty sure all the others you have to either use early startup or a boot loader that switches). So my first A4000 I just stuck on PAL, so that all the games would work. My secondary one I left on NTSC as I believe the Video Toaster requires it.


But that means if I want to play a game (in this case Hudson Hawk), I have to make sure to go into Early Startup and put the system into PAL mode, just switching to a PAL resolution isn't good enough.


So my question is, can't this be done directly with patching the whdload slaves? Seems to me the games mostly require the early boot because they ignire whatever the workbench screen is (in fact it creates its own on top, doesn't it?) Is there just an option I am missing? Any database out there of games that only work in PAL?
Don't use that jumper! Always use the early startup menu or some other tool to switch PAL/NTSC. That jumper seems to work fine at worst, but it causes AmigaOS to expect the correct crystal for that system instead of correcting for the different crystal.

E.g. if you have an NTSC A4000 and jumper it to PAL, it will assume you have a PAL crystal and time everything accordingly, even though you have an NTSC crystal. This will cause some subtle timing errors, in particular your system clock will drift.

If you do want to use that jumper, make sure you swap the crystal as well.
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Old 30 October 2019, 06:06   #4
slaapliedje
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Originally Posted by AmigaHope View Post
Don't use that jumper! Always use the early startup menu or some other tool to switch PAL/NTSC. That jumper seems to work fine at worst, but it causes AmigaOS to expect the correct crystal for that system instead of correcting for the different crystal.

E.g. if you have an NTSC A4000 and jumper it to PAL, it will assume you have a PAL crystal and time everything accordingly, even though you have an NTSC crystal. This will cause some subtle timing errors, in particular your system clock will drift.

If you do want to use that jumper, make sure you swap the crystal as well.
Whoa! I had no idea on that! Well crap, I wonder if that has been mucking with my PPC one then? How do you actually know you have a PAL 4000 or not, because I always thought that was kind of the reason Commodore put that on there, so they could just ship with a jumper set instead of a whole different board. Also, I thought the timing was all based on the crystal on the CPU card.
Edit: Holy crap, so all this time some of the random wonkiness was probably due to that. Freespace actually launched in OS4.1, but was gnarly for sure, under 3.9 it worked great (though I only got as far as loading up the docking bay after creating a pilot name). Gonna have to try some more things, would be wonderful if that fixed all my issues, I had no idea!

Last edited by slaapliedje; 30 October 2019 at 07:22.
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Old 07 November 2019, 13:54   #5
AmigaHope
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Quote:
Originally Posted by slaapliedje View Post
Whoa! I had no idea on that! Well crap, I wonder if that has been mucking with my PPC one then? How do you actually know you have a PAL 4000 or not, because I always thought that was kind of the reason Commodore put that on there, so they could just ship with a jumper set instead of a whole different board. Also, I thought the timing was all based on the crystal on the CPU card.
Edit: Holy crap, so all this time some of the random wonkiness was probably due to that. Freespace actually launched in OS4.1, but was gnarly for sure, under 3.9 it worked great (though I only got as far as loading up the docking bay after creating a pilot name). Gonna have to try some more things, would be wonderful if that fixed all my issues, I had no idea!
The board and chips themselves are exactly the same on PAL and NTSC A4000s (there is no chroma generator on it like on the A1200). The only difference between an NTSC and PAL A4000 is the crystal. The jumper is then set to tell the system that you have an NTSC or PAL crystal installed.

I made the same mistake as you initially, and jumpered my NTSC system to run in PAL by default, and it seemed to work fine at first. Then I noticed the longer I ran it the more messed up some things happened -- e.g. cryptographic connections like SSH and SSL would fail because timing checks were failing. Also timing in some games was off and would even cause some stuff like dropped frames.

Jumpering back to NTSC and just booting into PAL from early startup fixed those problems.

It all goes back to how NTSC crammed its colorburst into the existing 4.5Mhz black and white signal (not to mention slowed it by 1.001 to prevent interference, hence the 29.97fps) while PAL had more room in its 6Mhz bandwidth to fit the colorburst signal. It wound up such that it was pretty much impossible to make a single clock with high enough frequency to convert to the colorburst frequency of both systems with any easily-attainable division by an integer or simple fraction.
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