I2c Ardiuno Bridge to Edit Vsize

[darknezz19]

Got an ardiuno and downloaded one of Martin Hejnfelt's i2c projects to enable rgb on certain jungles. The git is below.

https://github.com/skumlos/tb1226en-i2c-bridge

My Jungle is a TA1268N, uses the same write address and read address as his jungle. Edited the code to just look for 09 offsets and edit the hex to change Vsize. Was having trouble getting it to work at first, but for some reason when my logic analyzer is hooked up to the i2c outputs that go to the jungle, it magically starts working. I'm not sure why yet, and need to figure that out. Edited the Vsize value manually and reuploaded to the ardiuno, Vsize was indeed changed. In the end my goal will to be to store an initial Vsize value, and then map a couple momentary switches to increase and decrease the value.

This will be great for GroovyMame setups. As many of your might already know, most all other geometry can be controlled with settings in the driver, except for Vsize. When this is done, which might take a while longer as I'm a green horn with C++, should be seamless to change that setting. No more having to go through the service menu when changing a game.

Big thanks to Martin for making his code open source, couldn't have started this without his initial code.

[Endprodukt]

Very cool project. I was thinking about something like that for some time now. I'm my case it would be possible with a digital potentiometer. It would have to be set on a per game basis though.

[darknezz19]

Thanks man. That's a cool idea with the digital pot.

Had some time and think I got it far enough along to show. Other people can edit the code to match their sets jungle chips register offset for Vsize, without too much fuss. I would think.

https://www.youtube.com/shorts/iaNxtEacty4

Here is a fork of Martin's wonderful original code with the Vsize control.

https://github.com/darknezz19/tb1226en-vsize-bridge

[R-Typer]

Hey, this is great! Will this work on Sony Trinitrons CRTs which have their own mind when positioning geometry is in question?

[darknezz19]

Should be the same for Sony sets. Comes down to the jungle that is used to find the registry offsets and bits in the data sheet. I read about another guy Jose who RGB hacked a Sony set over I2C, and he had to do some extra trickery to spoof a watchdog routine. Something to that effect. He wrote a blog about it. If I ever mess with a Sony I2C bus, I'll write up about it as well.

https://coredump.io/sony_rgb_mod/