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Author Topic: The ultimate VGA to SCART adapter  (Read 363 times)

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gambaman

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The ultimate VGA to SCART adapter
« on: August 13, 2019, 08:35:25 pm »
I have published here an enhanced version of my previous VGA to SCART adapter. Unlike the previous version, the new adapter does not require any external power source nor DC-DC converter to generate the 12V of the SCART status signal thanks to Visenri's indications. Also, the transistors employed to generate the RGB selection signal in the previous version are no longer needed. The adapter has the following pros:

  • It's cheap thanks to the unexpensive PIC16F18313.
  • It automatically detects the polarity of the input VGA sync signals and configures the configurable logic cells (CLC) of the PIC dynamically to generate the SCART composite sync signal correctly.
  • The PIC monitors the input signal and set the composite sync to ground if the frequency of the horizontal sync signal is wrong or if the vertical sync signal does not change. This is useful if you are using it to generate the Csync signal of a very old arcade monitor to protect it. Also, if any of the input sync signal is wrong then the PIC disables the the SCART RGB selection signal and the SCART status signal.
  • Most VGA devices can provide enough power to the PIC so no external power source is required.
  • No external power source nor DC-DC converter is required to generate the 12V of the SCART status signal. It can be generated by the PIC itself as noted by Visenri.
  • Optional aspect ratio selection (16:9 or 4:3).
  • Optional LEDs  to test the power and input sync signals.
  • Optional power source selection.
  • The basic circuit only requires the PIC and a pair of resistors and capacitors.
  • The full circuit fits in a (big) DE-15 enclosure using a single sided PCB and easy to solder through-hole components.



« Last Edit: August 13, 2019, 08:41:59 pm by gambaman »

buttersoft

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Re: The ultimate VGA to SCART adapter
« Reply #1 on: August 13, 2019, 10:06:45 pm »
Good stuff, i love building stuff like this so i'll give it a look.

And the more i look the more i like it. Very neat. And i like that you've included parts sourcing from reasonable places :)

I notice you've got a cable gland on the end of the DE-15 housing. Do you know where it came from?
« Last Edit: August 13, 2019, 10:28:04 pm by buttersoft »

gambaman

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Re: The ultimate VGA to SCART adapter
« Reply #2 on: August 14, 2019, 12:45:47 pm »
I notice you've got a cable gland on the end of the DE-15 housing. Do you know where it came from?

The SCART-SCART cable I employed for that prototype was very short. So, instead of cutting it into halves, I removed one of the male SCART connectors and used its gland for my DE-15. A better alternative is to cut a longer cable into halves. In that way you can use an only cable to make two adapters (one with each half).

Mr. Peabody

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Re: The ultimate VGA to SCART adapter
« Reply #3 on: August 20, 2019, 02:09:22 am »
Is there supposed to be audio in the video?.....

gambaman

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Re: The ultimate VGA to SCART adapter
« Reply #4 on: August 20, 2019, 10:08:55 am »
Is there supposed to be audio in the video?.....

I removed most of it. Only the corresponding to the sound test (minute 5 more or less) is left. I used to think I had the voice of James Earl Jones till I recorded it :(.

gambaman

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Re: The ultimate VGA to SCART adapter
« Reply #5 on: August 30, 2019, 05:44:01 pm »
Good stuff, i love building stuff like this so i'll give it a look.

I'm sorry if you already got the previous version of the PCB (labeled 1.2). I have realized that the DE-15 was hard to fit because its footprint was wrong  :embarassed:. I have just published a fixed version (labeled 1.4), but I haven't tested it yet.  I have ordered a few PCBs of the new version. I will test them and tell you the results as soon as possible.

buttersoft

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Re: The ultimate VGA to SCART adapter
« Reply #6 on: September 01, 2019, 08:44:08 pm »
Hah, no, i didn't order (yet). TBH i have like 6 projects on the go - encoders, SFC mods, CRT repair - and i don't strictly need a scart adapter. I'll get around to it eventually.