Search found 149 matches

by bmwtcu
12 Jul 2024, 23:54
Forum: Hardware and software hacking
Topic: Another FPGA Gigatron implementation
Replies: 6
Views: 1023

Re: Another FPGA Gigatron implementation

I didn't even know they used diodes. The way I work out the resistor values to use is to write a series of equations based on the Thevenin equivalent circuit with the 75ohm load and solve for the resistor values needed to achieve the target voltages. I'd have to go dig up my circuit analysis textboo...
by bmwtcu
10 Jul 2024, 07:28
Forum: Hardware and software hacking
Topic: Another FPGA Gigatron implementation
Replies: 6
Views: 1023

Re: Another FPGA Gigatron implementation

I'm also leaning towards the level shifter messing with the VGA timing or levels. I question what that RC circuit he's introduced on the VDDA rail would do to output. A scope capture of the SYNC pulses comparing the input and output levels would be instructive. TBH I really don't have a lot of exper...
by bmwtcu
28 Jun 2024, 06:16
Forum: Hardware and software hacking
Topic: Another FPGA Gigatron implementation
Replies: 6
Views: 1023

Re: Another FPGA Gigatron implementation

For some reason, I could not get an image out of the VGA connection. HSYNC/VSYNC work, as the controller also works. I looked at his constraints file and both his and the tang nano 9k schematic. He assigned the outputs to a 1.8V bank of pins and is using a 2.2k/4k voltage divider to get the 3.3V sw...
by bmwtcu
04 Jun 2024, 02:11
Forum: Hardware and software hacking
Topic: online gigatron emulator and CSP errors
Replies: 9
Views: 1646

Re: online gigatron emulator and CSP errors

I think it's under the PhilThomas Contrib folder in the GH repo. Also have you seen this? viewtopic.php?t=459
by bmwtcu
21 Feb 2024, 10:58
Forum: Kit assembly gallery
Topic: Hello! I made a Gigatron
Replies: 4
Views: 7573

Re: Hello! I made a Gigatron

Are you able to tell what IC the knock off controller uses inside? I'm assuming it's hidden under a glob top. If you have the parts handy, it's fairly trivial to build a CD4021B or 74xx165 based NES controller if you want a guarantee of compatibility. https://www.raphnet.net/electronique/arcade_cont...
by bmwtcu
18 Oct 2023, 11:05
Forum: Hardware and software hacking
Topic: Craps (Dice Game)
Replies: 4
Views: 2947

Re: Craps (Dice Game)

casino.png
casino.png (39.43 KiB) Viewed 2909 times
by bmwtcu
18 Oct 2023, 08:08
Forum: Hardware and software hacking
Topic: Craps (Dice Game)
Replies: 4
Views: 2947

Re: Craps (Dice Game)

Nice work Mike! Dude, first Poker then Craps... When are Slots, Roulette and Blackjack going to be released? I'll get started working on the Gigatron Casino setup. Congrats again!
by bmwtcu
08 Sep 2023, 08:00
Forum: Kit assembly gallery
Topic: New Gigatron in Russia
Replies: 8
Views: 7209

Re: New Gigatron in Russia

I'm still leaning toward overscan. Most modern TVs I've used have a PC mode that removes all post-processing like scaling, etc. If you don't have that, I'd suggest trying a native 4:3 monitor (not TV) if possible. Something old enough where 640x480 was actually tested! Where I'm at, I've picked up m...
by bmwtcu
07 Sep 2023, 16:32
Forum: Kit assembly gallery
Topic: New Gigatron in Russia
Replies: 8
Views: 7209

Re: New Gigatron in Russia

Is that a monitor or TV? If TV, does it have a overscan on/off or PC mode menu setting? Are you using 6.25MHz crystal or something different?
by bmwtcu
30 Aug 2023, 20:39
Forum: Hardware and software hacking
Topic: Simple graphics lib to port for glcc?
Replies: 2
Views: 1936

Re: Simple graphics lib to port for glcc?

I played around with the DJGPP version of Allegro decades ago for 8-bit graphics on a 486DX2/50 . Might be useful as inspiration for an API, but probably too complicated for what the Gigatron can reasonably handle. https://www.allegro.cc/files/?v=4.2