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Post by Pyrofer on Jun 1, 2016 21:40:15 GMT
postimg.org/image/zd4i8a1f7/So the resistors need tweaking and it looks a lot nicer in person than this photo but it works! A single chip programmable logic solution that turns the RGBI into RRGGBB to use with a 6bit resistor DAC. The brown fix is integrated as well and there is no blurring or fuzzing of the output due to pull up/down resistors and diodes. The circuit is so simple it's easy as 7 resistors, 6 (2 per colour) for the RGB and a single one for the composite sync output (inverted composite sync is also output). The chip is available as DIP and runs off 5v so no hard soldering or level conversion is needed Once I get the resistor values pinned down I will post some decent pictures of how nice the output looks.
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Post by Pyrofer on Jun 13, 2016 21:19:30 GMT
Another pic here. Dear god the camera does not pick this up well. It looks much nicer in person. The different shades of colours stand out much better on screen than on camera. Still, it works perfectly with a single GAL and 7 resistors. I declare this topic done! s5.postimg.org/4k773yxme/IMG_3287.jpgUPDATE - Forget that rubbish picture. The final image is this, s5.postimg.org/hami1ksl3/Full_Size_Render.jpgThat is the real output on a C128 real hardware to a SCART TV. I am now looking at making a PCB to hold all the parts.
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Post by Pyrofer on Jul 26, 2016 19:18:32 GMT
So I redesigned the circuit using a better Lattice GAL. I am having a PCB made and putting S-Vid/Audio passthrough on it from the VIC (using the DIN as a source of 5v). This should hopefully be the last time I ever make a video adaptor for the 128. Unless I get random and try to fit the RGB to S-Vid on the PCB too and put input switching etc etc....
Scope creep eh.
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Post by mrbombermillzy on Jul 27, 2016 21:05:08 GMT
Thats a great looking palette there Pyrofer.
I will make a mental note to ask you for the exact resistor values when I can get back to dealing with my 128 again, as the circuit that I built is made up from a mix of guesswork and the resistors that I had lying about. A near perfect colour match like that would be a good move.
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Post by Pyrofer on Jul 27, 2016 22:02:51 GMT
Hah. I used "what I had handy" too.
Pretty sure it's 1k and 500ohm for the 2 bits per colour. I think it was meant to be 1k and 470ohm but I had no 470s so I just stacked 2 1k in parallel...
When I get the PCBs in and make up the "finished" product I will retake some photos with the 1k/470r in place.
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Post by Pyrofer on Aug 18, 2016 11:30:01 GMT
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Post by molebrain on Aug 18, 2016 13:12:27 GMT
was bedeutet diese Kosten für Sie, für mich zu machen? My solder skills are terrible. Can you make this for me?
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Post by Pyrofer on Aug 18, 2016 13:57:42 GMT
Funny you should say that. I have 10 PCBs I am assembling. I think quite a few are spoken for via my FB post, but in theory yes.
I think they will retail for £30 when I account for the full BOM and assembly time.
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Post by molebrain on Aug 18, 2016 15:14:42 GMT
Are you on Facebook? I must follow you then. 30 is quite reasonable! Put me on the list Anybody who wants, you can find me at www.facebook.com/tonyrocks
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Post by Pyrofer on Aug 18, 2016 21:18:00 GMT
I posted in both the 128 Enthusiasts and 64/128 groups if you are a member on either.
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