Re: [stella] PAL/NTSC issues

Subject: Re: [stella] PAL/NTSC issues
From: <kurt.woloch@xxxxxxxxx>
Date: Mon, 18 May 1998 09:54:27 +0200
Chris Wilkson wrote:

>>>1) a difficulty or console switch to toggle.
>>>2) two separate assemblies.

>> profitable, like it was then. So in my opinion, Version 1) would be
>> better nowadays. But that uses up one difficulty or console switch. So
>> the question would be if there's a way for the software to tell whether
>> it runs on PAL or NTSC without requiring the user to tell it to the
>> program.

>Production run wouldn't be affected that much.  Randy makes the carts in
>very small quantities, maybe even to order...I don't know.  There's nothing
>physically different between the formats, just burning different code into
>the EPROMs.  So the stumbling block falls back to the programmer.  If he/she
>wants to create two rom images to save code space, it's his/her choice.  But
>it isn't mandatory.  Just my 2 cents...

So you're doing EPROM's now? I thought most early games were produced on
ROMs? Do you know if any commercial sold games used EPROM's back in the

Another question concerning EPROM's: Could it be that they lose their
memory after, let's say, ten or twelve years? My Mangia and Pitfall II
carts seem to be broken. Could this be the reason for that? (Now that's
a case where downloading the BIN from the Internet IS legal... no?)

>I think this was all discussed before, but I'll mention this one item.  If
>you want to include the option for any format, simply latch the value of
>a console switch.  You still use extra ROM and 2 bits of RAM
>but you don't lose a switch in the process.

Could you please explain further what this (latching a console switch
value) means?

And from Robin Harbron:

>I can't think of a way of getting the 2600 to do it (telling if it runs on
PAL or NTSC), but I'm sure most
>other computers can - the C64 can do it very easily, since the current
>scan line is always located in the high bit of $d011 and all of $d012...
>Those 9 bits will count up to 261 or 262 on an NTSC C64 (depending on
>the VIC revision) and 311 on a PAL C64.  I know Amigas can cope with
>it as well.

Yes, the Amigas can - in most of the cases. Still, sometimes they guess
wrong, and come up with an NTSC screen with the lower 56 lines empty on
a PAL system.

And from Piero Cavina:

>BTW, I haven't yet found a PAL tv which can't sync to the NTSC version of
>Oystron, so this feature could be considered useless.. but it's great fun
>to switch the mode on the fly, and see the TV lose sync for a couple of
>seconds... :-)

It should affect game speed too... since PAL is 50 Hz and NTSC is 60 Hz,
it should run 20% faster on NTSC. Or did you take care of that too?
In this case, I really consider *purchasing* an Oystron cart (as it was
stated in the survey we all should fill out). Is it easy to get one to
Austria (from Italy, or whereever it's produced), or does the paying
issue make it impossible? Has anyone got experience with the paying

A few years ago, I went to a friend who also had an Amiga with some cart
that allowed switching the output signal to 60 Hz. His Amiga 1081
monitor synced to it, too... so I suppose mine also would. The only
trouble could be the VCR I have to use in-between the VCS and the
monitor, cause the 1081 hasn't got a tuner.

With love (and many frames to sync to...)

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