HD 6450 with DVI-I and DisplayPort - good for PC+TV build?

[SBYT]

Greetings - I'm working on a PC + TV build. I picked up a 6450 512mb and after reading various guides online I was hoping it would fit my needs. I read this post from Calamity and I'm not sure if a 5450 with a VGA port would be better. https://geedorah.com/eiusdemmodi/forum/viewtopic.php?pid=1052#p1052

"As a note, I have a HD 6450 which is externally identical to my HD 5450, with both DVI and VGA connectors. However, in this case the card has only 1 analog output, on the VGA connector, therefore Analog_0 is the right option. This confused me at the beginning because the DVI port on this card has the hole pattern of a DVI-I (digital/analog), however it's actually a DVI-D (digital-only). Beware of this."

My 6450 doesn't have a VGA port, it only has a standard looking DVI-I (Dual Link) port and a display port, nothing else. Is there a chance that the DVI-I is not going to output an analogue signal?

Card is almost identical to one like this: https://www.ebay.co.uk/itm/192899709741?hash=item2ce9b7fb2d:g:lTwAAOSwzrlbWzHN


Saying my card works, is it right to think that I can output through a DVI to VGA cable/connector + UMSA + scart cable to my CRT TV once I have all the drivers installed and configured?
https://arcadeforge.net/UMSA/UMSA-Ultimate-SCART-Adapter::57.html

I've included a picture of the card, I don't have the physical card yet so this is just a picture from the place I bought it.

Thanks!

[buttersoft]

It's vanishingly unlikely that DVI port won't do analog. And crt_emudriver can output composite sync, so you shouldn't need the USMA, just a cheap VGA-to-SCART cable from ebay to get started.

EDIT: oh wait, you might need 5V (~3V) for your SCART blanking. The cheap VGA-to-SCART cable might not come with a wire for that at all, IDK. Which leads you back to needing the USMA, i guess... unless you're happy wiring a cable up for yourself

[Zebidee]

I agree with Butters.

Except I don't trust most of the VGA-SCART cables I see online, you never know whats in them, so I make my own.

What TV are you using, and what inputs does it support?

[SBYT]

Greetings and thank you for your quick responses! 

The TV is Sony Trinitron KV-25X5K. It has two SCART ports and some other things - I've attached images.

I was hoping I could get a cheap DVI to VGA adapter and then use a cable like this to take the signal to the TV:

https://www.ebay.co.uk/itm/263775409959?hash=item3d6a3d5727:g:dq8AAOSwKJlbLk-z

I found a really nice guide that I could probably use to make my own cable, but when considering my lack of electrical skills and ordering parts, if the cable above is suitable I will just order that.

http://forum.arcadecontrols.com/index.php?topic=160869.0

Would a DVI to VGA adapter like this be enough, or should I be looking out for something specific?

https://www.ebay.co.uk/itm/353409441486?hash=item5248d81ece:g:tGwAAOSwXBxgQTsc

Other alternative is to take the 6450 512mb back and swap it for a 5450 1gb card that has a VGA port on the board (not ribbon), costs bit more but I wouldn't need an adapter for the DVI port.

[Zebidee]

That cable you linked to looks like it will do the job - I'd also bet it is built with gambaman's Ultimate PIC or similar (that you also linked to) to get 12v from 5v USB port and do composite sync.

That DVI-I adapter looks good. The analogue signals are carried via the group of pins at one end - the large flat "tongue" is for ground, with 2 pins above and 2 pins below for RGB+sync.

Try to avoid using the HD5450 if possible. Getting CRT-emulator to work with them is difficult. Ironically, you need to use a DVI-VGA adapter and some arcane tricks to make it work properly (outputting 15khz via the VGA head as primary).

[SBYT]

That cable you linked to looks like it will do the job - I'd also bet it is built with gambaman's Ultimate PIC or similar (that you also linked to) to get 12v from 5v USB port and do composite sync.

That DVI-I adapter looks good. The analogue signals are carried via the group of pins at one end - the large flat "tongue" is for ground, with 2 pins above and 2 pins below for RGB+sync.

Try to avoid using the HD5450 if possible. Getting CRT-emulator to work with them is difficult. Ironically, you need to use a DVI-VGA adapter and some arcane tricks to make it work properly (outputting 15khz via the VGA head as primary).

Great, thanks!

Thanks for the heads up about the 5450, I'll stick with the 6450 and see how I get on when everything arrives. In the description for that VGA-SCART cable it says "USB 5V + 12V connector included" It seems the maker is selling them with gaming in mind, so I would assume it should be suitable. They've also got cables with an audio jack, or a molex instead of USB:

https://www.ebay.co.uk/itm/253144420758?hash=item3af0955196:g:Iz4AAOSw38BaT0ds
https://www.ebay.co.uk/itm/253706610409?hash=item3b1217a6e9:g:eqQAAOSwAspbLkRI

[Zebidee]

Yeah the cables look good, right stuff. When I started in this hobby ~15 years ago, nobody made those cables commercially so I made them for myself. Then, after the kids were in bed, I'd get busy making them at the kitchen counter for other BYOACers. But I can't compete with their price from the kitchen table. 25-30 euros is pretty good considering the efforts involved.

One thought: I have a VGA-VGA dongle based on gambaman's PIC. It is designed to only pass 15khz signals and creates composite sync from H+V inputs. It works well with my VGA-SCART cables and GreenAntz transcoders. However I've tried it with composite sync input (via setting in CRT_EMU) and it didn't work. It needs H+V.

If these cables use the same PIC technology, they might not work with a DVI-VGA adapter (as it can only pass composite sync)!!!!

Might be worth asking them some questions first about what kind of sync inputs the cable will work with, and whether it will work with an adapter or not.

[buttersoft]

...might not work with a DVI-VGA adapter (as it can only pass composite sync)!!!!

Wait, what? A simple passive adapter just passes both. Or did you mean something else besides the below?

[Zebidee]

Buttersoft, you are right!!  I was wrong   I thought there was no vertical sync passed through because it isn't there in that analogue cluster of 5 pins.

I was about to say otherwise, but then re-checked a pinout carefully and found a pin labelled vertical sync, hiding there in the main cluster of pins (pin . Checked it out with the DMM (using a DVI-I to VGA adapter and a VGA male-male cable) and it definitely passes to the VGA Vsync pin.

Good news then, and thanks for correcting me. Attached a pic of the DVI-I pinout for reference.

Pinout pic attribution:
By Ionuion at English Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4379981

...might not work with a DVI-VGA adapter (as it can only pass composite sync)!!!!

Wait, what? A simple passive adapter just passes both. Or did you mean something else besides the below?

[bobbyb13]

As this (hopefully) remains within topic here...

Then what actually is the difference between DVI-D and DVI-I that renders DVi-D useless for our purposes here.
I have learned that there is a difference between these types of cables also (even though they look the same?) and that is problematic too.

[Zebidee]

As this (hopefully) remains within topic here...

Then what actually is the difference between DVI-D and DVI-I that renders DVi-D useless for our purposes here.
I have learned that there is a difference between these types of cables also (even though they look the same?) and that is problematic too.

DVI-VGA adapters make much more sense to me now I know there is a Vsync pin.

There is a DVI-I that carries both digital and analogue signals, and all the header pins are there. For our needs we usually want DVI-I.

DVI-D only does digital, and the little cluster of analogue pins won't even be there. There is also a DVI-A which is analogue only, but have never seen it myself.

[SBYT]

Thanks all for the input. Once I get all my pieces delivered I will see how it all works together!

[Osirus23]

.

[snappleman]

FWIW I used the 5450 and a 6450 and they both work well, I've had no issues getting crt_emudriver working on any of my 5450 cards.

Instead of using converters (and since i have a couple dozen DVI-I cables that have racked up over the last 20 years) I splice a SCART connector to the end of a DVI-I cable with all the analog outputs, ground, composite sync, or if a card won't do composite sync a very simple passive combiner circuit (diode on hsync, resistor on vsync, combined into csync) and then depending on the sync voltage a 75-480ohm resistor that takes the voltage down with the sync termination in the TV. I also take the 5v from the DVI connector and run it through a 220 termination cap and resistor on the SCART connector to act as a blanking signal since my TVs don't need 12v to switch to RGB. I also solder in a 1/8" phono cable to the audio inputs on the scart connector that run through the housing to the line out on the back of the PC since I use a switcher that's routed to TV+sound amp.

The main reason I started doing this was not just to have less bulk sticking out the back, but because I don't like feeding TTL sync from the GPU right into a consumer TV. I've had one instance where TTL sync from a neo geo MVS damaged the sync input on the TVs IC, and tracking down an exact model 25+year old chroma IC is enough of a pain that I'd rather just make sure that sync voltage (and RGB voltage as well) is always correct for the circuit it's going into.

[Zebidee]

Making a dedicated DVI-I to SCART cable is a creative and direct way to avoid both needing an adapter and the painful process to swap the primary video "head" on a 5450 card.

Is the diode there to prevent negative Hsync pulses during the Vsync pulse? Circled in blue, at bottom, in attached picture. Pic shows H+V sync combined by simply twisting H+V wires together and running through a resistor to a TV.

FWIW I used the 5450 and a 6450 and they both work well, I've had no issues getting crt_emudriver working on any of my 5450 cards.

Instead of using converters (and since i have a couple dozen DVI-I cables that have racked up over the last 20 years) I splice a SCART connector to the end of a DVI-I cable with all the analog outputs, ground, composite sync, or if a card won't do composite sync a very simple passive combiner circuit (diode on hsync, resistor on vsync, combined into csync) and then depending on the sync voltage a 75-480ohm resistor that takes the voltage down with the sync termination in the TV. I also take the 5v from the DVI connector and run it through a 220 termination cap and resistor on the SCART connector to act as a blanking signal since my TVs don't need 12v to switch to RGB. I also solder in a 1/8" phono cable to the audio inputs on the scart connector that run through the housing to the line out on the back of the PC since I use a switcher that's routed to TV+sound amp.

The main reason I started doing this was not just to have less bulk sticking out the back, but because I don't like feeding TTL sync from the GPU right into a consumer TV. I've had one instance where TTL sync from a neo geo MVS damaged the sync input on the TVs IC, and tracking down an exact model 25+year old chroma IC is enough of a pain that I'd rather just make sure that sync voltage (and RGB voltage as well) is always correct for the circuit it's going into.

[snappleman]

Is the diode there to prevent negative Hsync pulses during the Vsync pulse? Circled in blue, at bottom, in attached picture. Pic shows H+V sync combined by simply twisting H+V wires together and running through a resistor to a TV.

That's how it's set up but I don't know if it's necessary or if it really does much. I tried combining the two lines one time, it didn't work so I looked into the simplest circuit possible, and this one worked, at this point I do it just to feel like I have something there doing "something", just for peace of mind I guess.