[Coco] SCART to HDMI project.

CoCo Demus retrocanada76 at gmail.com
Tue Jun 13 17:52:50 EDT 2017


just try first with 1 nor. should work in most cases

On Tue, Jun 13, 2017 at 2:36 PM, Doug Fraser <frase072 at telus.net> wrote:

> Yes, by using 4 NOR gates should produce an XNOR circuit to combine the
> h-sync and v-sync signals off the RGB connector.  That would be a 7402 TTL
> chip. I'll try that because, I  think getting a 74266 XNOR chip will be
> hard to find where I live.
> Doug Fraser
>
>
> Sent from my Samsung Galaxy smartphone.
> -------- Original message --------From: CoCo Demus <
> retrocanada76 at gmail.com> Date: 2017-06-13  14:08  (GMT-08:00) To:
> CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> Subject:
> Re: [Coco] SCART to HDMI project.
> Try a NOR, it should work
>
> On Tue, Jun 13, 2017 at 1:41 PM, Dave Philipsen <dave at davebiz.com> wrote:
>
> > 74266 XNOR is not a very common chip.   I'm sure I don't have one in my
> > parts bin.  But you can do the same logic with a couple of 7400s (which
> is
> > probably *the* most common TTL chip).
> >
> > Dave
> >
> > > On Jun 13, 2017, at 1:43 PM, Salvador Garcia via Coco <
> > coco at maltedmedia.com> wrote:
> > >
> > > I had never heard of an XNOR gate, I had to look it up! 74266 :-)
> > Salvador
> > >
> > >
> > >
> > >      From: Doug Fraser <frase072 at telus.net>
> > > To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> > > Sent: Tuesday, June 13, 2017 1:18 PM
> > > Subject: Re: [Coco] SCART to HDMI project.
> > >
> > > I was just thinking that. I might have a xnor chip in my collection.
> > Good to know about pin 10. Thanks for that. Will investigate and post my
> > findings.
> > > Doug Fraser
> > >
> > >
> > > Sent from my Samsung Galaxy smartphone.
> > > -------- Original message --------From: CoCo Demus <
> > retrocanada76 at gmail.com> Date: 2017-06-13  11:03  (GMT-08:00) To:
> > CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> Subject:
> > Re: [Coco] SCART to HDMI project.
> > > Also should be a XNOR gate, because the signals are inverted on coco3.
> > >
> > > On Tue, Jun 13, 2017 at 11:03 AM, CoCo Demus <retrocanada76 at gmail.com>
> > > wrote:
> > >
> > >> Yes, you need to add a XOR TTL combining h-sync and v-sync and you can
> > >> disconnect the pin-10 and use it on the RGB connector. the pin-10 is
> > used
> > >> only for the cm-8 for a strange detection system, all this
> undocumented.
> > >>
> > >>> On Tue, Jun 13, 2017 at 10:33 AM, Doug Fraser <frase072 at telus.net>
> > wrote:
> > >>>
> > >>> That's possible. A good question is where should we get the h-sync
> and
> > >>> v-sync signals from? The project suggests the centre pin from the
> > composite
> > >>> video to pin 20 on the scart connector (sync in). Is there a way to
> > combine
> > >>> the rgb sync signals to replace the composite sync signal?
> > >>> Doug Fraser
> > >>>
> > >>>
> > >>> Sent from my Samsung Galaxy smartphone.
> > >>> -------- Original message --------From: CoCo Demus <
> > >>> retrocanada76 at gmail.com> Date: 2017-06-13  07:14  (GMT-08:00) To:
> > >>> CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> > Subject:
> > >>> Re: [Coco] SCART to HDMI project.
> > >>> For what you are describing: black and white, black stripes looks to
> me
> > >>> you
> > >>> connected coco3 composite video into a scart luma input.
> > >>>
> > >>> On Mon, Jun 12, 2017 at 11:36 PM, Barry Nelson <
> > >>> barry.nelson at amobiledevice.com> wrote:
> > >>>
> > >>>>> frase072 frase072 at telus.net  <mailto:coco%40maltedmedia.com
> > >>>> ?Subject=Re%3A%20%5BCoco%5D%20SCART%20to%20HDMI%20project.&
> > >>> In-Reply-To=%
> > >>>> 3Ctqar0lch5fyvl7tt6iq19drr.1497324709423%40email.android.com%3E>
> > >>>>> Mon Jun 12 23:31:49 EDT 2017
> > >>>>>
> > >>>>> Just picked up an SCART to HDMI converter to replace my aging CM-8
> > >>>> monitor. After following Barry Nelsons project on hackaday.io I
> have
> > >>> had
> > >>>> partial success with a video image. Partial in that I have a black
> and
> > >>>> white screen and colors are grey scaled and artifacted with vertical
> > >>> black
> > >>>> lines. I'm not sure what is going on with the signal.  Does anyone
> > that
> > >>> has
> > >>>> done this project have any insights as to how to make this work?
> > >>>>> Doug Fraser.
> > >>>> Can you post a picture of the screen? Make sure you connected all
> the
> > >>>> ground wires and that you have 5 volts applied to the 100 ohm
> > resistor.
> > >>>> Double check all your wiring and measure the voltage on pin 16.
> Maybe
> > >>> you
> > >>>> got a bad converter, post a photo of the wiring also please, I may
> be
> > >>> able
> > >>>> to help more after I see the pictures.
> > >>>>
> > >>>> --
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> > >>>>
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> > >>
> > >>
> > >
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