Project: HDMI/DVI out for STFM

Progress on our FPGA cores.
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exxos
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Re: Project: HDMI/DVI out for STFM

Post by exxos »

Smonson wrote: 01 Sep 2018 08:52 I can't guarantee that the buffer will be fast enough for the 32MHz clock though, I recommend checking it on a scope before depending on it.
OK, what chip did you use ?
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Re: Project: HDMI/DVI out for STFM

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exxos wrote: 01 Sep 2018 10:34 OK, what chip did you use ?
74LVC245A
https://assets.nexperia.com/documents/d ... CH245A.pdf
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Re: Project: HDMI/DVI out for STFM

Post by poobah »

Smonson wrote: 01 Sep 2018 10:52
exxos wrote: 01 Sep 2018 10:34 OK, what chip did you use ?
74LVC245A
https://assets.nexperia.com/documents/d ... CH245A.pdf
Have you guys looked at the IDT QuickSwitch devices?
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exxos
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Re: Project: HDMI/DVI out for STFM

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poobah wrote: 02 Sep 2018 15:41 Have you guys looked at the IDT QuickSwitch devices?
I'm using them :)
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Re: Project: HDMI/DVI out for STFM

Post by troed »

Smonson wrote: 01 Sep 2018 10:52
exxos wrote: 01 Sep 2018 10:34 OK, what chip did you use ?
74LVC245A
https://assets.nexperia.com/documents/d ... CH245A.pdf
Seems plenty fast according to that spec sheet, unless I'm misunderstanding something.
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exxos
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Re: Project: HDMI/DVI out for STFM

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troed wrote: 02 Sep 2018 16:37 Seems plenty fast according to that spec sheet, unless I'm misunderstanding something.
I think it was just a suggestion..Nothing wrong with those of course.

For my stuff, I am pushing every MHz out of everything, so the IDT switches have pretty much zero delay, which is what I need. In case of the FPGA stuff, a few ns isn't going to make any odds. Though I guess the IDT stuff may be easier to solder as they (IIRC) are larger packages.
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Re: Project: HDMI/DVI out for STFM

Post by poobah »

exxos wrote: 02 Sep 2018 16:57 ... Though I guess the IDT stuff may be easier to solder as they (IIRC) are larger packages.
Yup, I solder them by hand fairly easily.
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Re: Project: HDMI/DVI out for STFM

Post by Smonson »

The only reason I mention the buffer is that the one I used for the 16MHz line (M74VHC1GT125DF2G) can't hack it at 32MHz. Since 16MHz is not too fast by today's standards I didn't worry about it when selecting buffers.
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rpineau
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Re: Project: HDMI/DVI out for STFM

Post by rpineau »

May I suggest the NB3N551 for clock buffering :

https://www.mouser.com/datasheet/2/308/ ... -83648.pdf
Working ones : MegaSTE (68020) / TT030 / Falcon with AB040 & Eclipse / 1040STF
Need testing : Falcon with CT2
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Smonson
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Re: Project: HDMI/DVI out for STFM

Post by Smonson »

Suggestions are welcome. But from the datasheet it looks like this device is only guaranteeing to produce a 2.4v high. Dunno if the Atari would be too happy with that.

But this is definitely the kind of thing I should have used in the first place

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