0xCats wrote on 2022-05-31, 23:31:

When you want to add PCI-e and AGP to something that only does PCI.
Just small things one works on, as I do...
Screenshot_20220601_012856.jpeg

This brings up more questions… whatcha workin on there….? 😁

That would sound great on a mini-itx PCI only board that might be installed into a micro or full atx case on its empty space. I imagine that IC on the corner would be a PLX like bridge.. if I've to imagine how such idea might be, I'd imagine it with a PCI specific empty card having a sort of IDE connector to connect it to the second multiple bus board so to have a stable config without bus flat cables moving (considering anyway the amount of current that would pass through the connector which is a problem). Maybe even considering a PSU connector to surpass the 25/30 watts limit of the PCI bus that is a problem which is not said already PSU powered video cards actually solve cause we don't know how much is required from the bus and from the connector.

Sphere478 wrote on 2022-05-31, 21:50:

https://old.pinouts.ru/Slots/agp_pinout.shtml […]
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weedeewee wrote on 2022-05-31, 21:36:

Sphere478 wrote on 2022-05-31, 21:22:

Really? They put a usb connection in agp?

Did most mainboards hook it up? Or leave them blank?

That is something you must find out and share with the world !

My feeling is that it was hardly ever connected.

https://old.pinouts.ru/Slots/agp_pinout.shtml

Looks like it’s true

Of course 5v and gnd can be taken from any pin with that signal, the only thing left is data plus and minus

This thing also exists, unclear if it is using the port signal or not though.

HP Powered USB AGP Card for RP5000, PN: 325201-001

Some graphics cards also contained peripheral ports, like the ATI 8500DV All-in-Wonder. This card contained a 1394 FireWire port, however I'm not sure if it received any speed advantage from the AGP port compared to the case whereby a firewire port was located on a PCI expansion card. I used to use this firewire port to connect to an external firewire HDD.

sdz wrote on 2020-09-23, 17:51:

Something like this? […]
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Something like this?

20200624_184104.resized-1024x365.png
20200624_1841042.resized-1024x365.png

Even made a bracket for the V5 😀
20200624_183901-1024x665.jpg
20200624_183924-1024x634.jpg

I designed it a couple of months ago, AGP 1.0 1x (3.3V only), 4 layer board with uninterrupted ground plane under PCI signals, properly terminated unused AGP signals, 12V PCIe power input, 3.3V/5V switching power supplies which can deliver more power than the AGP specs require, separately filtered AGP VIO, high speed level shifters, it can work in any 3.3V/5V PCI slots, 33/66MHz jumper (if the mobo supports PCI 66MHz ofc), 2 fan headers with support for 5V/12V 3pin/4pin fans and adjustable PWM.

I just want to ask, if these are your cards, could you tell me what bus level shifters you are using on the AGP to PCI card? The usual TI multi bit bus switches?
I'm already making a PCI to Universal AGP adapter for old boards, I'm just curious if you ever considered using correct voltage clamping for true Universal AGP support.

In my case I'm using TI SN74TVC16222A adjustable voltage clamps to selectively switch 5V or 3.3V PCI to 3.3V or 1.5V signals. Also fwiw, this is far from trivial due to PCI's unterminated bus with reflected wave switching.
Lots of high speed oscilloscope time and tweaking required.

scheiss_freak wrote on 2022-05-30, 13:59:

For a headless build I'm currently working on, I did not want to leave the bandwidth of the AGP port unused. But when looking f […]
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For a headless build I'm currently working on, I did not want to leave the bandwidth of the AGP port unused. But when looking for information online about using the AGP port for anything else than a graphics card you won't find much, except between the lines of this thread maybe. In most other forums when people have been asking about it, they'd be misdirected by some troll with an answer somewhat like "That's not possible because - you know - AGP stands for Accelerated GRAPHICS Port" So I had to search for information elsewhere. And I found some in the AGP Wikipedia article:

An AGP bus is a superset of a 66 MHz conventional PCI bus and, immediately after reset, follows the same protocol.

Now that’s some information I was looking for. Further investigations also lead me to this thread. But as nobody seems to have built the adapter I'm after, I began to tackle it myself. I usually prefer to build prototypes before designing and ordering PCBs so I also chose to try the manual way first in this case. PCI and AGP riser cards were quickly sourced and as soon as I got them the port of the AGP riser was ripped off and wired straight to the PCI riser according to the AGP and PCI specs. After finishing the adapter I noticed that I didn’t have a PCI graphics card at hand and I therefore had to test it blindfolded. So I plugged in an HP NC370T PCI-X Gigabit Ethernet card into the AGP port of my testbed, fired it up and tried to SSH into it. And it worked. Just like that. I still can’t really excite myself about it, as it was just too easy. Usually stuff like that never works on the first try.

IMG_5422.JPG
IMG_5426.JPG

After the handbuilt prototype proved that an adapter of this kind is working I started to design a PCB according the AGP spec for impedance and length matching. The PCBs are now finally in and work really well. So far any network card I’ve tried worked flawlessly. Compatibility with SATA RAID cards seems to be more problematic. Of all the RAID controllers I’ve tried, only the Adaptec 2820/2420SA works well enough on the AGP to be usable. If the connected card and the underlying system have the capabilities the full 32bit 66 MHz PCI bandwidth of ~250 MB/s can be achieved.

IMG_5424.JPG

I naturally got a few of the PCBs made, so if anyone is interested, please get in touch. As I still can't send private messages, please include an e-mail address in your pm.

If I may add, the main cause for incompatibility with some cards is the lack of the signals INTC (A7), INTD (B8), IDSEL(A26) and LOCK(B39) on the AGP bus. The lack of Interrupt C and D though is a major issue.
PCI Cards that rely on these will not function or function incorrectly in an AGP slot.

Perhaps that helps.

Thanks for the feedback.

My assumption is, that the missing LOCK pin is causing the problems with cards/drivers relying on it. The four PCI Interrupts are wire-ored to the two AGP interrupts, which is the same what a motherboard with more than 4 PCI devices does. IDSEL is connected to AD16 which is also common practice. So there shouldn't be any issues there. As the missing LOCK can't be really fixed in hardware and is more a software/driver issue I currently don't see a fix for it other than hacking device drivers, which is outside of my scope for now.

I just finished testing a simple SiI 3512 based SATA adapter on the AGP and it worked flawless.

I've setup a simple ordering page for the adapter and other stuff I'm working on:
https://recnas.org/

scheiss_freak wrote on 2022-06-23, 08:51:

Thanks for the feedback. […]
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Thanks for the feedback.

My assumption is, that the missing LOCK pin is causing the problems with cards/drivers relying on it. The four PCI Interrupts are wire-ored to the two AGP interrupts, which is the same what a motherboard with more than 4 PCI devices does. IDSEL is connected to AD16 which is also common practice. So there shouldn't be any issues there. As the missing LOCK can't be really fixed in hardware and is more a software/driver issue I currently don't see a fix for it other than hacking device drivers, which is outside of my scope for now.

I just finished testing a simple SiI 3512 based SATA adapter on the AGP and it worked flawless.

I've setup a simple ordering page for the adapter and other stuff I'm working on:
https://recnas.org/

This is exactly the kind of mad science that gets me up in the morning.

All considered, fully assembled that price is pretty fair. I kinda feel like I need one. If not to use, just to have in my collection 😂

Sphere478 wrote on 2022-05-31, 21:50:

Of course 5v and gnd can be taken from any pin with that signal, the only thing left is data plus and minus

This thing also exists, unclear if it is using the port signal or not though.

HP Powered USB AGP Card for RP5000, PN: 325201-001

They're pretty cheap on ebay. I'm inclined to pick one up just for the hell of it

@scheiss_freak I'm thinking of getting an agp to pci adapter from the order page you posted, but couple questions- Do you ship to US, and why does it only work with 66mhz pci? What will happen if used in a 33mhz pci slot? I have an old Powermac G3 I'd wanted to try it out on since I have quite a few agp macintosh video cards that aren't good enough for my faster macs but would be perfect in a G3. It does have a 66mhz slot intended for a graphics card, but was still wondering why 66mhz only.

scheiss_freak wrote on 2022-06-23, 08:51:

Thanks for the feedback. […]
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Thanks for the feedback.

My assumption is, that the missing LOCK pin is causing the problems with cards/drivers relying on it. The four PCI Interrupts are wire-ored to the two AGP interrupts, which is the same what a motherboard with more than 4 PCI devices does. IDSEL is connected to AD16 which is also common practice. So there shouldn't be any issues there. As the missing LOCK can't be really fixed in hardware and is more a software/driver issue I currently don't see a fix for it other than hacking device drivers, which is outside of my scope for now.

I just finished testing a simple SiI 3512 based SATA adapter on the AGP and it worked flawless.

I've setup a simple ordering page for the adapter and other stuff I'm working on:
https://recnas.org/

Order placed 😀

Are the mounting holes the same as this: looks like no, what bracket should I try to use?

I don't think I've seen any cards with an adapter bracket. I typically see 3D printed brackets for things like this.

f34rthereaper wrote on 2022-07-08, 21:27:

@scheiss_freak I'm thinking of getting an agp to pci adapter from the order page you posted, but couple questions- Do you ship to US, and why does it only work with 66mhz pci? What will happen if used in a 33mhz pci slot? I have an old Powermac G3 I'd wanted to try it out on since I have quite a few agp macintosh video cards that aren't good enough for my faster macs but would be perfect in a G3. It does have a 66mhz slot intended for a graphics card, but was still wondering why 66mhz only.

Thanks for your interest, yes, we are shipping to the US.

Edit: Rereading your question, I think you misunderstood the use of my adapter. It is intended to install PCI cards in an AGP slot, i.e. server-grade Ethernet or Sata adapters in headless systems, or modern 66 MHz capable PCI graphics. Not the other way around. Anyway, here's my answer regarding the 66 MHz only operation:

With the introduction of 66 MHz PCI one of the former GND pins on the PCI slot was changed to be the M66EN pin. This pin allows the host system to signal 66 MHz capable operation by pulling this pin high. 33 MHz cards will still have this pin connected to GND and when inserted in a 66 MHz bus, pull the signal low forcing the host to fall back to 33 MHz operation on this bus. A 66 MHz capable card can read the state of this pin to determine, whether it's connected to a 33 or 66 MHz bus. As the AGP only supports 66 MHz operation, it does not have the M66EN pin. To signal 66 MHz operation to cards installed in the adapter the M66EN pin of the adapter's PCI interface is hardwired to 3.3V. Hardwiring it instead of using a pullup resistor makes manufacturing a lot easier as by doing so the adapter doesn't require any components to be populated on the PCB. If you want to try it and run a 33 MHz card at 200% of its intended operating frequency you can cut the trace between the solder jumper connecting M66EN and VDDQ and install a 1 to 10 kOhm resistor instead. The connected card will still run at 66 MHz, but you won't risk any damage to the rest of the system, by potentially shorting 3.3V to GND.

Oh yeah, that should definitely be through a resistor.

Which pin is this? A? B? What number?

I should make note of this pin for my 3.3v adapter.

Sphere478 wrote on 2022-07-10, 19:38:

Oh yeah, that should definitely be through a resistor.

Which pin is this? A? B? What number?

I should make note of this pin for my 3.3v adapter.

google books tells me it's B49

weedeewee wrote on 2022-07-10, 20:48:

Sphere478 wrote on 2022-07-10, 19:38:

Oh yeah, that should definitely be through a resistor.

Which pin is this? A? B? What number?

I should make note of this pin for my 3.3v adapter.

google books tells me it's B49

Thx 😀

I would be genuinely curious to see if USB is functional on any of these AGP slots.

Would love to get my hands on a AGP to PCI adapter. Couldn't find it on eBay. Re: What retro activity did you get up to today?

It occurs to me that a pci-x/pci 64-bit to agp adapter would be very welcome among those with server boards.

of course this would either be an active adapter (is there such a chip?) or it would be basically passive and just use the extra pins for more power and only be 32-bit

My kingdom for an AFFORDABLE pci-x (66/64) to pci-e adapter.

I asked a certain easy to Google company if they had any then their site said sold out. A week later they "found a box with some" at $300 a pop.

Thanks but no thanks.

luckybob wrote on 2022-07-27, 13:18:

My kingdom for an AFFORDABLE pci-x (66/64) to pci-e adapter.

I asked a certain easy to Google company if they had any then their site said sold out. A week later they "found a box with some" at $300 a pop.

Thanks but no thanks.

Why not share the deets?

I don't feel good about throwing someone under the bus when they went out of their way to find the product, but I didn't want to pay the price.

It wasn't startech, but https://www.pridopia.co.uk/8114.html