[v1.2] MECB V9958 or V9938 VDP RGBS Video Card

[epaell]

Filling in memory with each of the primary colours produces the expected colours - so I've got my bits right (I'm kind of believing it isn't a software issue). Setting all of them to the maximum results in a not-quite-white display (and also with slight vertical bands). I might need to grab another monitor to see if it is any different and/or try a different converter for the RGB to HDMI.

[epaell]

Ah OK, turns out it was just my cheap and dodgy monitor. Tried a better monitor and things are looking better now:

Better monitor

[Editor]

... Tried a better monitor and things are looking better now:

Looking really good. Love the colour detail of the image you've loaded!

[jeremyspx]

I would like to build that board but I have two questions:
1) Is the ATF17V8 pal chip available pre-programmed? Alternatively do you have a map of its functions so that I can have one programmed for me please?
2) I see you're outputting RGBS and I haven't seen a display that uses that Sync signal - (sorry for my ignorance)

Many thanks!

[Editor]

I would like to build that board but I have two questions:

The complete kitset (including the PCB only, and optional packs to make the full kitset), is available from my Tindie store here:
https://www.tindie.com/products/38551/

1) Is the ATF17V8 pal chip available pre-programmed? Alternatively do you have a map of its functions so that I can have one programmed for me please?

One of the optional packs (on the Tindie listing), is for the "Programmed ATF16V8 PLD".

But, you can also find all the resources on the MECB Github repository (if you want to modify, or program the ATF16V8 yourself).

2) I see you're outputting RGBS and I haven't seen a display that uses that Sync signal - (sorry for my ignorance)

RBGS was common for retro consoles and computers (that supported a RGB output).

The actual connector used is based on the Sega MegaDrive console (which supported RGB output), which was chosen as it makes it easy (and relatively cheap), to find pre-made suitable video cables.

I believe most RGB input displays are either Sync on Green (3 inputs - RGB), or seperate Sync (4 inputs - RGBS). Also, VGA uses RGBHV, which is seperate Horizontal & Vertical Sync.

I use a GBS Control based video convertor, which takes in a SCART based RGBS signal, and outputs VGA to my VGA monitor.

[epaell]

I purchased the programmed PLD option pack when I ordered my board and it worked a treat - I can also program them myself but I liked having the option of having it pre-programmed as it is one less potential point of failure in terms of me doing something wrong.

I previously used the GBS Control based video convertor but more recently I switched to using this:

https://www.amazon.com.au/dp/B07Z5W7QS7 ... in_title_1

It's handy because it plugs straight into the 99x8 board and converts to HDMI which most modern displays support (I only had one really poor quality LCD monitor that supported VGA and it had terrible image quality), the device also passes through the audio if you have that plugged in and your monitor/TV supports it. It's a little bit on the pricey side but still cheaper than the GBS Control option and didn't require messing with a SCART connector.

[Editor]

I previously used the GBS Control based video convertor but more recently I switched to using this:

https://www.amazon.com.au/dp/B07Z5W7QS7 ... in_title_1

It's handy because it plugs straight into the 99x8 board and converts to HDMI which most modern displays support (I only had one really poor quality LCD monitor that supported VGA and it had terrible image quality), the device also passes through the audio if you have that plugged in and your monitor/TV supports it.

Nice find! That looks like a perfect & compact all-in-one solution. The audio pass-though to HDMI being an added bonus!

I've got a several GBS Control solutions, one also with HDMI out. But they were pricey, quite large and also needing the Mega Drive SCART cable.

I think I'll add one of these to my Amazon Cart, for my last purchase of 2025.

[Editor]

... more recently I switched to using this:

https://www.amazon.com.au/dp/B07Z5W7QS7 ... in_title_1

Thanks again for sharing this link. I ordered one straight away, and it arrived today (from the UK).

It's a really good solution. A nice quality HDMI display output (possibly because it's specifically for the Sega?).

It's also nice and compact, no additional cables needed, and is actually cheaper than going down the GBS Control route.

In fact, the only thing is, I would've preferred the Sega cable to have been a little longer.
I think it's about 45cm (18 inches). If it had been 60cm minimum, then I'd give it my unequvical "10 out of 10" rating!