Sporniket's log on hardware stuff

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Atarian Computing
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Re: Sporniket's log on hardware stuff

Post by Atarian Computing » Tue Feb 16, 2021 6:59 am

Very nice. Although I'd use two ground planes if you have one unused.

sporniket
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Re: Sporniket's log on hardware stuff

Post by sporniket » Tue Feb 16, 2021 5:12 pm

Yes, I was also thinking about having a power plane. What would be better between {2 ground planes} and {1 ground plane + 1 power plane} ?

Atarian Computing
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Re: Sporniket's log on hardware stuff

Post by Atarian Computing » Tue Feb 16, 2021 5:30 pm

sporniket wrote:
Tue Feb 16, 2021 5:12 pm
Yes, I was also thinking about having a power plane. What would be better between {2 ground planes} and {1 ground plane + 1 power plane} ?
For this I think two grounds in the middle would be better.

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Re: Sporniket's log on hardware stuff

Post by sporniket » Sun Feb 21, 2021 8:17 pm

Now waiting for my board to be produced and delivered. (This time I hope that the delivery service will do its work properly :x )

It's time to work on the firmware. I got a working toolchain and IDE (I'm using VSCode with platformIO and I got to make it work with ESP IDF framework), and I got re-acquainted with C/C++ programming.

After a hours of brainstorming, I finally came up with a software design that looks nice. I had a hard time because I want to replace the two ACIAs at the same time, each having separate data streams and status/command registers. Another difficulty is the choice of words/concept/metaphores (insert here any esoteric/philosophic quote stating that words fools the mind).

And now I have a nice diagram (sorry, in French)
2021-02-21--01.jpg
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sporniket
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Re: Sporniket's log on hardware stuff

Post by sporniket » Sat Feb 27, 2021 11:30 am

Study of VHDL, finally got a 4bits adder with sync signals and CCR working as expected...
vhdl_adder_sim.png
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sporniket
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Re: Sporniket's log on hardware stuff

Post by sporniket » Thu Mar 11, 2021 11:19 am

Today I finally got my first pcbs. I feared that the last mile delivery service would lost my parcel -again-, but all is well.

In front on the picture, this is a custom made protoboard I made for my attempt at implementing the gbscontrol project : 4 lanes of breadboard style holes (equivalent to 2 bread board side by side) and 2 linkables pair of rails (one rail for vcc, one rail for ground)

In the back, the pcb for my project of replacing the pair of ACIAs by one ESP32 devkitc to use bluetooth HID devices (game controller, mouse and keyboard) and bluetooth MIDI. When checking with my devkit, I feared that the holes where to tight to fit, but it turns out that the pin strips is a little bit bended. With another devkit, it fits, yay ! Now I have to make an order at mouser to populate this little board...
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sporniket
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Re: Sporniket's log on hardware stuff

Post by sporniket » Sun Mar 21, 2021 10:08 pm

Writing C++ hurts so much, compared to Java... Well I could make do with good old C, but I so much love object oriented programming that I will continue a little bit...

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Re: Sporniket's log on hardware stuff

Post by sporniket » Sat Mar 27, 2021 5:31 pm

Today I had some time alone, I felt like building my little circuit to convert hsync/vsync to csync to plug on that infamous gbs-8200, in the hope to get it works (spoiler : it did not... :( )

I'm wondering if i should connect one of the ground pin from the vga coming from the ST to the ground pin of my circuit ?

2021-03-27--01-hvsync-to-csync.jpg
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2021-03-27--04-fail.jpg
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sporniket
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Re: Sporniket's log on hardware stuff

Post by sporniket » Wed Mar 31, 2021 9:32 pm

Tonight I had enough motivation to look into this contraption again. I checked continuity of all the wire, and it was ok.

Then I bogde-wired the ground from the video output of the ST to the circuitry, thinking that it would not hurt. (And it did not hurt :D)

2021-03-31--01-bodge-wire.jpg
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Then I tested again, and got the same result... However, I took the time to fiddle with the settings (I found how to display the OSD in english)... And it turns out that I MUST set the display as 640x480 to get something :

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Well, it's something... I have another one, the color is better. And both seems to convert the picture once.

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All in all it's crappy, I was expecting that, and I guess that I have a knock-off of a knock-off. I may continue to build the gbscontrol project though, but without haste. Since this STE has a modulator, I will get some proper cable to link it to the tv-set, I may get a good surprise.

Still I feel satisfied that I got some result with my Hsync+Vsync=>Csync convertor

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Re: Sporniket's log on hardware stuff

Post by sporniket » Sat Apr 03, 2021 12:29 am

Continuing a little bit on this project. I eventually realized that
  • I have not stressed enough that the gbs convert one frame, and that's all, I have to cycle through input source or display size to get a new frame converted
  • BUT the frame position is always the same, giving me hope that I have a working csync signal, albeit out of sync with rgb signals.
  • my initial schematics was made for the internal creation of csync inside the computer
  • I was probably slowly killing the gbs by outputing a 5V signal in the resulting csync.
So, I simplified the schematics, given that I will use the 3.3v power supplied by the ESP8266 dev board (nodemcu v3).

2021-04-03--01-simplification-of-schematics.jpg
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(what is not clear on this schema is that the ground from vga is directly wired to the ground of the gbs)

Then I use my custom made protoboard to put the csync generator and the nodemcu in place. For now nodemcu board will just be used as a overpriced power supply :D

2021-04-03--02-build.jpg
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(I also checked and put the colors potentiometers to the left, to get better colors)
And then, time to test...

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I get the same result, with a simpler circuitry. I am also pleased with the colors that are more vivid. Next step will be to flash the nodemcu board and make the mod of the gbs to finally test gbscontrol.

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