Re: NTSC VIC-II timing

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Thu, 22 Jun 2017 08:25:03 +0200 Message-ID: <efc40ee3-f205-20bc-f7a7-2166b9ca53aa@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 06/21/2017 09:02 PM, Segher Boessenkool wrote:
> On Wed, Jun 21, 2017 at 08:51:34PM +0200, Gerrit Heitsch wrote:
>>>>> What about HMOS and NTSC? 8565 is only PAL, right? What's been used on
>>>>> narrow NTSC boards? Or weren't there actually any?
>>>>
>>>> That would have been the 8562 for the C64 and the 8564 for the C128.
>>>
>>> Admittedly never seen any of the two. Can those also be distinguished from
>>> their NMOS counterparts with the collision based detection?
>>
>> No idea, the code I found spoke about PAL... But I would assume that
>> those parts of the circuit would be the same between PAL and NTSC.
> 
> The only difference between PAL and NTSC should be the contents of the
> X and Y comparator arrays.  I've never seen a die pic of any NTSC VIC-II,
> so no idea if that is actually true...  But I cannot think of any other
> difference currently.

Well, the color generator should be a bit different since PAL and NTSC 
differ in that respect. The overall differences are small enough that 
you can make a chip that is switchable between PAL and NTSC as the 8360 
TED proves.

  Gerrit

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