[Coco] is there any existing 6847 output to RGB ? (for coco2)

[Zippster]

Ah, now feeding the clock to the 6847 from a flip-flop makes sense.
They are actually pausing it while inserting the extra lines.

- Ed


> On Feb 21, 2015, at 12:54 AM, didier derny <didier at aida.org> wrote:
> 
> Finally I have an explanation on the use of 525 lines chip on a 625 line tv
> 
> http://users.on.net/~clockmeister/VZ300/VZ300-tech-ref-man.pdf
> 
> check page 6, they are doing a 525 lines to 625 lines conversion
> the same way as on the Alice (and probably the mc 10 PAL)
> 
> this conversion is done by the chips  Z18/Z19/Z20
> 
> this information comes from mc10/alice lovers on a French forum
> 
> --
> didier
> 
> 
> -----Message d'origine-----
> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Zippster
> Envoyé : jeudi 19 février 2015 22:13
> À : CoCoList for Color Computer Enthusiasts
> Objet : Re: [Coco] is there any existing 6847 output to RGB ? (for coco2)
> 
> Probably "close enough”.  Does it say anywhere in the files you found what ic Z20 is?
> Weird way to run a clock to the 6847.
> 
> - Ed
> 
> 
>> On Feb 19, 2015, at 3:02 PM, didier derny <didier at aida.org> wrote:
>> 
>> Btw apparently on the alice the clock is not 3.5795... but 3.55
>> 
>> -----Message d'origine-----
>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Zippster 
>> Envoyé : jeudi 19 février 2015 21:54 À : CoCoList for Color Computer 
>> Enthusiasts Objet : Re: [Coco] is there any existing 6847 output to 
>> RGB ? (for coco2)
>> 
>> Not familiar with the SECAM standard, but the flip-flop is clearly used to adjust the sync.
>> 
>> - Ed
>> 
>> 
>>> On Feb 19, 2015, at 2:50 PM, didier derny <didier at aida.org> wrote:
>>> 
>>> When this machine was sold, it was not so common to find a TV with 
>>> PAL Most were only SECAM, PAL+SECAM were really expensive
>>> 
>>> Later PAL+SECAM TV around 1990 where very common
>>> 
>>> 
>>> 
>>> -----Message d'origine-----
>>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Luis 
>>> Antoniosi (CoCoDemus) Envoyé : jeudi 19 février 2015 21:43 À :
>>> CoCoList for Color Computer Enthusiasts Objet : Re: [Coco] is there 
>>> any existing 6847 output to RGB ? (for coco2)
>>> 
>>> It's flip-flop. It must be used to convert the NTSC sync to PAL sync.
>>> 
>>> 
>>> Luis Felipe Antoniosi
>>> 
>>> 
>>> 
>>> On Thu, Feb 19, 2015 at 3:36 PM, didier derny <didier at aida.org> wrote:
>>> 
>>>> The schematics I discovered:  http://6809.eu/schema_alice4k.png
>>>> The mc10 schematics:          http://6809.eu/schema_mc10.png
>>>> 
>>>> --
>>>> didier
>>>> 
>>>> -----Message d'origine-----
>>>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de 
>>>> Zippster Envoyé : jeudi 19 février 2015 21:28 À : CoCoList for Color 
>>>> Computer Enthusiasts Objet : Re: [Coco] is there any existing 6847 
>>>> output to RGB ? (for coco2)
>>>> 
>>>> Yes, if it’s just a bunch of transistors (no comparators or adc) 
>>>> then it must be mixing the component signals to RGB while keeping it all analog.
>>>> 
>>>> I’m working on one (Digitize —> RGB —> DAC —> VGA) but have a way to 
>>>> go yet.
>>>> 
>>>> - Ed
>>>> 
>>>> 
>>>>> On Feb 19, 2015, at 2:16 PM, Luis Antoniosi (CoCoDemus) <
>>>> retrocanada76 at gmail.com> wrote:
>>>>> 
>>>>> Well I do have a coco2 peritel with a RGB output for SCART TVs. It 
>>>>> does everything on transistors, actually a transistor plantation...
>>>>> 
>>>>> I think it does a YCbCr -> RGB conversion. The VDG outputs YCbCr.
>>>>> 
>>>>> 
>>>>> Luis Felipe Antoniosi
>>>>> 
>>>>> 
>>>>> 
>>>>> On Thu, Feb 19, 2015 at 3:04 PM, didier derny <didier at aida.org> wrote:
>>>>> 
>>>>>> Is there any existing 6847 output to  rgb board / schematics
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> I've just seen the pinout of a RGB video connector
>>>>>> 
>>>>>> But the video in the machine is done by a 6847
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> The schematics are hard to read  and there are a lot of 
>>>>>> transistors
>>>>>> 
>>>>>> Between the video signal on the 6847 and the connector.
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
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>>>>> 
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