CoCoVGA upgrade

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unumlapis
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CoCoVGA upgrade

Post by unumlapis » Wed Sep 04, 2019 4:55 pm

Just in time getting back from vacation I got the CoCoVGA kit from Brendan and hopefully I get time to install it this upcoming weekend and I'm going for the mounting of the button board (which also carries the VGA DIN jack) within the Dragon case; so 5 holes to be drilled. So just a matter of where it would fit and look at it best :)

Here is a snap of the unboxing and content of the CoCoVGA kit and follow-up with some picture from the upgrading process as well once I'm at that step.
CoCoVGA_Unbox.jpg
CoCoVGA_Unbox.jpg (1.21 MiB) Viewed 2123 times

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unumlapis
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Re: CoCoVGA upgrade

Post by unumlapis » Thu Sep 05, 2019 8:04 am

So got both D32 and D64 and only one CocoVGA - which one to upgrade and to make it more interesting to the D64 I also have the Dragon 200E lower-case daughterboard which haven't mounted yet. While it's two totally different boards, would it make since to have both cards in the D64?

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robcfg
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Re: CoCoVGA upgrade

Post by robcfg » Thu Sep 05, 2019 10:00 am

If the two boards worked well together then it would be excellent!

In any case, I’d choose the 64 or 200, the one you are more comfortable with.

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unumlapis
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Re: CoCoVGA upgrade

Post by unumlapis » Thu Sep 05, 2019 10:50 am

Did check with Brendan and while he haven't verified himself he had reports that the cards should work together. But the combo of the 80-column display and the CoCoVGA card really sounds nice :D

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unumlapis
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Re: CoCoVGA upgrade

Post by unumlapis » Mon Sep 09, 2019 7:40 pm

Right, then got some tome earlier this evening to desolder the MC6847 VDG video chip and this gave me also the opportunity to try out my new desolder gun which work out as expected and quite speedy procedure. So first step locating and desoldering:

dragon64_mc6847vdg.jpg
dragon64_mc6847vdg.jpg (127.16 KiB) Viewed 2060 times

And once done here is the result:

dragon64_mc6847vdg_desoldered.jpg
dragon64_mc6847vdg_desoldered.jpg (172.54 KiB) Viewed 2060 times

Next up is the mounting and soldering of 40-pin IC-socket:

dragon64_mc6847vdg_ic-socket.jpg
dragon64_mc6847vdg_ic-socket.jpg (167.8 KiB) Viewed 2060 times

First test with the original MC6847 VDG to verify that the operation went well :)

dragon64_mc6847vdg_testing.jpg
dragon64_mc6847vdg_testing.jpg (163.93 KiB) Viewed 2060 times
So far so good, the system works and then it's time to move on to the next step! :D

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unumlapis
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Re: CoCoVGA upgrade

Post by unumlapis » Mon Sep 09, 2019 7:46 pm

So let's mount the CoCoVGA and see how it works out:

dragon64_cocovga.jpg
dragon64_cocovga.jpg (145.2 KiB) Viewed 2060 times

Wow! That totally looks so nice with this sharp picture from the Dragon 64 and it might be to sharp for some and it's really about preferences when it comes to how much one should tweak the system. And then again, the original output is still there if I missed it...

dragon64_cocovga_beetronic4-3image1.jpg
dragon64_cocovga_beetronic4-3image1.jpg (98.26 KiB) Viewed 2060 times

And a close up....

dragon64_cocovga_beetronic4-3image2.jpg
dragon64_cocovga_beetronic4-3image2.jpg (213.48 KiB) Viewed 2060 times

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unumlapis
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Re: CoCoVGA upgrade

Post by unumlapis » Mon Sep 09, 2019 7:55 pm

Now, let's give it a try with the CoCoVGA board together with the Dragon 64 200 Computer Lower Case Daughterboard - 200E and see how that works out. First test is just the 200E board itself:

dragon64_E200.jpg
dragon64_E200.jpg (143.09 KiB) Viewed 2060 times

Works fine, but missing out the sharp image from the CoCoVGA, so let's stack the cards:

dragon64_E200_CoCoVGA1.jpg
dragon64_E200_CoCoVGA1.jpg (190.96 KiB) Viewed 2060 times

Close up:

dragon64_E200_CoCoVGA2.jpg
dragon64_E200_CoCoVGA2.jpg (133.7 KiB) Viewed 2060 times

But, sadly this combo didn't work out and don't know whether I stack them the other way around or if there is anything that I missed out, so open for suggestions. Or this might not just work at all. Here is what I get from the CoCoVGA:

dragon64_E200_CoCoVGA_output.jpg
dragon64_E200_CoCoVGA_output.jpg (176.91 KiB) Viewed 2060 times

The output from the Dragon 64 still works and without any issues but it's the CoCoVGA that ran in to some trouble...

sorchard
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Re: CoCoVGA upgrade

Post by sorchard » Tue Sep 10, 2019 8:40 am

Thanks for sharing. That's a nice, sharp picture!

I wonder if the problem with the stack of boards is that the display data is being translated via character rom two times. The lower case daughter board is feeding translated data to the CoCoVGA, and then the CoCoVGA is translating the data again. (If you look closely at the image you can see that characters with a column of pixels in the middle like 1, I and T have been replaced with something that looks like an H. i.e. a pixel value of 8 getting translated into the pattern for character 8)

Perhaps there is a mode setting on the CoCoVGA for this situation? I don't know much about it unfortunately.
Stew

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unumlapis
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Re: CoCoVGA upgrade

Post by unumlapis » Tue Sep 10, 2019 4:54 pm

Next try is to stack the cards with the CoCoVGA first and then the E200 card which actually worked:

dragon64_CoCoVGA-200E.jpg
dragon64_CoCoVGA-200E.jpg (154.3 KiB) Viewed 2013 times

But seems that the E200 board is disabled based on that the system is showing the standard Dragon cursor. One step closer maybe to get this to work or not. No big deal as the primary thing for this upgrade was the CoCoVGA. Also, after that I fixed the keyboard with some contact spray all keys now works as it should so now it possible to write a small chr$ loop to test the screen with default ASCII characters:

dragon64_cocovga_test.jpg
dragon64_cocovga_test.jpg (132.66 KiB) Viewed 2013 times

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unumlapis
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Re: CoCoVGA upgrade

Post by unumlapis » Mon Nov 04, 2019 9:31 pm

Moving forward slowly and finally got the time this evening to mount the CoCoVGA button board on system. I didn't want to have the port on the dragon case top so aligned the drilling template against the top lower edge and against the power supply port which worked out fine.
d64_CoCoVGA_Button_Board.jpg
d64_CoCoVGA_Button_Board.jpg (2.16 MiB) Viewed 1283 times

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