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Post by Pyrofer on Nov 10, 2016 16:47:58 GMT
Nice! You went for a couple things I considered then scrapped in favour of price/size.
I was originally using the 16v8 too and had planned to use 2 of them just as you have. I decided on balance that I only needed 2 bits per channel on the output for completely reasonable colours. I later swapped to PLCC (I originally used DIP) GALs with more pins, but didn't bother adding any more bits for colour as I didn't see a need.
I had success without the need for either an input buffer or output amp so dropped those too to reduce the size of the board.
On Balance I should probably have put some caps on the audio and video output. You've done some lovely work there. Are you planning to sell them or was it for personal use only?
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Post by molebrain on Nov 10, 2016 17:46:28 GMT
 I am glad that there is more interest in the 128 and specifically the VDC output. That was my goal when I started making my first adapter. I want everybody to be using the 128 in 128 mode with 80 col software. Your design looks extremely well done! It would be great if you could share some details about the circuit design and what you put in and why.  Where can I buy your adapter!? |
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Post by Pyrofer on Nov 10, 2016 19:20:44 GMT
which one are you talking about? If it's mine, I am waiting for PCBs that appear to have been sent on the slowest boat from China ever.
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rbm
Windows User
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Post by rbm on Nov 10, 2016 20:13:19 GMT
Are you planning to sell them or was it for personal use only? I am not planning to sell the adapter and only done for fun. If someone wants to do it, I can share the schematics and programs. Also I can provide the programmed plds because such programmers are expensive and it is nonsense to buy one just for this purpose. |
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Post by molebrain on Nov 10, 2016 20:18:38 GMT
which one are you talking about? If it's mine, I am waiting for PCBs that appear to have been sent on the slowest boat from China ever. Yours of course! It looks like it works. I'm terrible with solder and shaky hands anymore  |
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Post by robertb on Nov 10, 2016 20:38:37 GMT
Because that is what the VDC 80 column output USES. If you don't want CGA then you don't want 80 column. I'm talking about the colors. When John Carlsen (whose C128 Video DAC adapter is at www.bit-c128.com ) and I looked at a comparison of the colors of the C128's 80-column mode with that of CGA colors, we noticed that certain C128 colors were not the same as CGA colors. At one time, he even considered a way to switch between C128 color mode and CGA color mode. Fortunately, he decided to build his adapters with C128 colors (and thus if you use his adapter with CGA, then those colors will be slightly off). To get those accurate C128 80-column colors, he measured the video signals at the DAC in Commodore 1084S monitors. (A bit of trivia... not even Bil Herd, lead engineer for the C128, knew the video color values when he was asked.) Truly, Robert Bernardo Fresno Commodore User Group www.dickestel.com/fcug.htm |
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Post by Pyrofer on Nov 10, 2016 20:46:59 GMT
Yes, I remember comparing mine to John's one, the colours were quite close. I think the misunderstanding is talking about "colours" instead of "shades". I am pretty sure the names of each colour are the same for 128 and CGA, they are just slightly different shades of each colour. So the question comes how well calibrated the CGA monitors back in the day were? I bet if we took all three adapters, mine, this one and John's the colours would be quite close molebrain - Mine was on sale on Amibay. If you registered your interest you will be in the queue. Sadly the PCBs are taking aaages to arrive. I might even consider just ordering a new batch instead of waiting. There are more changes I want to make now after seeing this board anyway I didn't expect to be making a V3 but I just might have to. |
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Post by molebrain on Nov 10, 2016 20:58:36 GMT
Yes, I remember comparing mine to John's one, the colours were quite close. I think the misunderstanding is talking about "colours" instead of "shades". I am pretty sure the names of each colour are the same for 128 and CGA, they are just slightly different shades of each colour. So the question comes how well calibrated the CGA monitors back in the day were? I bet if we took all three adapters, mine, this one and John's the colours would be quite close molebrain - Mine was on sale on Amibay. If you registered your interest you will be in the queue. Sadly the PCBs are taking aaages to arrive. I might even consider just ordering a new batch instead of waiting. There are more changes I want to make now after seeing this board anyway I didn't expect to be making a V3 but I just might have to. ah! Thanks for the info! So, aside from this, what was the typical experience for a c-128/80 column user back in the day? A 1902 Monitor? I seriously can''t remember. As you can see from my Avatar, I only had a B/W tv |
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Post by robertb on Nov 10, 2016 20:59:44 GMT
I think the misunderstanding is talking about "colours" instead of "shades". Ah, shades. Well, the intensity of the colors are different between the C128 and CGA. And of course, any adapter has to take into account the brown color fix. Truly, Robert Bernardo Fresno Commodore User Group www.dickestel.com/fcug.htm |
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Post by robertb on Nov 10, 2016 21:05:48 GMT
molebrain wrote: > what was the typical experience for a c-128/80 column user back in the day? A 1902 Monitor? Yes, there were Commodore 80-column monitors (like 1080, 1902, 1084), Magnovox/Phillips, Sears LXI, and even Sony. Probably missing a brand or two, Robert Bernardo Fresno Commodore User Group www.dickestel.com/fcug.htm |
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