Thank you. 🙂👍

User derSammler has a bit experience with CEG hardware, I believe.

His Schneider VGA AT System 70 CEG has the CEG upgrade.: My Schneider AT Towers

CEG would be extra nice on modern LCD monitors. 🙂
Aliasing makes things look so unpleasant.

I just wanted pass along the following link that has a PDF with a really good article in Analog Devices Number 3, Volume 24, 1990. Analog Devices RAM DAC used the Edsun CEG scheme in their implementation. Sounds like it would basically be the same thing as the one from Edsun Laboratories. You may be able to source one of these as well to try out. I have however been unable to find any online.

https://www.analog.com/en/analog-dialogue/art … hances-vga.html

Thanks for sharing this, I hope you can share some pictures if you spot any differences. Looks like they're drop-in replacements for DIP28 / PLCC44 RAMDACs from that era.

If that Polish seller is who I think it is, they sell good parts. Actually new if it says it's new and the packaging is very sensible for sensitive / easily damaged chips.

Thermalwrong wrote on 2023-06-06, 23:53:

Thanks for sharing this, I hope you can share some pictures if you spot any differences. Looks like they're drop-in replacements for DIP28 / PLCC44 RAMDACs from that era.

If that Polish seller is who I think it is, they sell good parts. Actually new if it says it's new and the packaging is very sensible for sensitive / easily damaged chips.

The seller from Poland on eBay is tvsat_electronic. Attached is a photo of the Edsun CEG RAMDAC chip from their eBay listing. Notice the date code on the chip of 9037. Definitely from the 37th week of 1990 and exactly from the time period these chips were released.

Yep that's the one 😀 I bought some SiS chipset QFP chips from them and they were new with no solder on the legs and packaged properly. Your chips should be good too I suspect.

Should be interesting to see if it works and if it makes an appreciable difference. Since you're working with the DIP version rather than the PLCC44 version, the pinout should be the same as most RAMDACs in that package. I did notice a couple of CEG specific pins on the PLCC44 version though, which are n/c on regular RAMDACs.

Thermalwrong wrote on 2023-06-07, 00:24:

Yep that's the one 😀 I bought some SiS chipset QFP chips from them and they were new with no solder on the legs and packaged properly. Your chips should be good too I suspect.

Should be interesting to see if it works and if it makes an appreciable difference. Since you're working with the DIP version rather than the PLCC44 version, the pinout should be the same as most RAMDACs in that package. I did notice a couple of CEG specific pins on the PLCC44 version though, which are n/c on regular RAMDACs.

At the very least it should act as a normal 8-bit color RAMDAC if it is truly a drop in replacement. To get the Anti Aliasing features, you need to include that logic in your graphics code. Too bad it is not automatic, but we are talking 1990 technology after all:)

jasa1063 wrote on 2023-06-07, 01:21:

At the very least it should act as a normal 8-bit color RAMDAC if it is truly a drop in replacement. To get the Anti Aliasing features, you need to include that logic in your graphics code. Too bad it is not automatic, but we are talking 1990 technology after all:)

The ebay listings say they're ADV476 compatible which would only be 6-bit color (18-bit RGB).

jmarsh wrote on 2023-06-07, 02:10:

jasa1063 wrote on 2023-06-07, 01:21:

At the very least it should act as a normal 8-bit color RAMDAC if it is truly a drop in replacement. To get the Anti Aliasing features, you need to include that logic in your graphics code. Too bad it is not automatic, but we are talking 1990 technology after all:)

The ebay listings say they're ADV476 compatible which would only be 6-bit color.

Thanks for the correction!

The ADV7148 datasheet show more information on how those CEG RAMDACs work. Even provides code examples:

ViTi95 wrote on 2023-06-09, 09:08:

The ADV7148 datasheet show more information on how those CEG RAMDACs work. Even provides code examples:

Thanks!

I was also able to source a ADV7146 CEG RAMDAC from tvsat_electronic in Poland. It should be interesting to see if this is much different the Edsun CEG EL171 RAMDAC.

Seems they are quite similar: https://tvsat.com.pl/PDF/E/EL171_EL.pdf

I've also bought the EL171 from the same tvsat_electronic

I got the Edsun EL171 CEG RAMDACs today. I installed one and did some testing. Static images look fine, but when doing cycle cycling the picture has interference. I think the issue may be that the EL171 is running at 50MHz and the Samsung RAMDAC I took out runs at 80MHz. I have a ADV7146 coming and I hope that one will work out better.

50 vs 80MHz is maximum pixel clock rating, and pixel clock depends on currently selected resolution. 50MHz one tops out at 1024 x 768, the 80MHz one allows 1028 x 1024. When used at 320/640 x 200/400/480 this will not be a limiting factor at all.

I am curious to see photos of the effects of this stuff, some before and after type things if possible ~

jasa1063 wrote on 2023-06-13, 03:29:

I got the Edsun EL171 CEG RAMDACs today. I installed one and did some testing. Static images look fine, but when doing cycle cycling the picture has interference. I think the issue may be that the EL171 is running at 50MHz and the Samsung RAMDAC I took out runs at 80MHz. I have a ADV7146 coming and I hope that one will work out better.

I spoke a little bit too soon. I tried the video card and Edsun RAMDAC in different computer and all is working normally. I think the issue is I am running bus timings a little too aggressive on the other computer for the video card too handle.

Here is PV a DOS picture viewer that supports the Edsun CEG and .CEG files. I have not been able to locate any .CEG files but I am attaching the program in case anyone is interested. The PV.DOC file is in German, so I ran it through Google Translate and I have included the translated PV-EN.DOC file in the zip archive.

There was an SDK for the Edsun CEG RAMDAC. Analog Devices acquired Edsun Laboratories in 1991. I have been unable to locate it anywhere including using archive.org to search Analog Devices website as far back as 1997. Anyone know where a copy can be found?

I've got and tested the EL171CEG chips today, and they work perfectly fine on my OTI-087X. Video output is a bit worse compared to the original MX86487PC, as black colors are now mostly grey. Very similar to what S3 Trio cards output.

Now time to have some fun programming this chip, I'll update with whatever I find of out.

jasa1063 wrote on 2023-06-14, 02:07:

Here is PV a DOS picture viewer that supports the Edsun CEG and .CEG files. I have not been able to locate any .CEG files but I am attaching the program in case anyone is interested. The PV.DOC file is in German, so I ran it through Google Translate and I have included the translated PV-EN.DOC file in the zip archive.

That's cool, thank you! 😃

Back in the 90s, PV was my favorite Picture/MPEG/FLI player. Even used it on Windows 98SE! 🙂

I'm not sure if it's the same program I remember, can't test right now. 🤷‍♂️

Here's a backup of the latest versions I've found.