PSX Link Cable

[Jahreeva]

I’m sure this is a long shot but is there system link support in the core? I was just watching a video on wipeout 2097 and remembered that this was a thing. I know its super niche and I can’t think of many titles that used it but still I would love some system to system wipeout.

[djsquare]

I think it would be cool for DOOM. That was the only game I remember using it for back in the day and man it took so much effort to put 2 TVs, and 2 PS1s together and find power for everything, just the have the space for this one time event with the kids down the street who you didn't really like that much anyway. I don't know, there are so many features FPGAzumSpass is adding and perfecting that this is probably not really high priority idea.

Side note: Was anyone else slightly bothered that the HDMI mod kit for PS1 removes this port?

[PistolsAtDawn]

I think it would be cool for DOOM. That was the only game I remember using it for back in the day and man it took so much effort to put 2 TVs, and 2 PS1s together and find power for everything, just the have the space for this one time event with the kids down the street who you didn't really like that much anyway. I don't know, there are so many features FPGAzumSpass is adding and perfecting that this is probably not really high priority idea.

Side note: Was anyone else slightly bothered that the HDMI mod kit for PS1 removes this port?

Haha! Oh, man. That's exactly how so many of those sorts of features worked out for me in my youth. Never used because of the effort required, then utterly lackluster when you do go to the trouble.

[taz07rx]

Back to the time I use to play Destruction Derby with this link feature.

My best friend had also a PSX and we spent many time to play in 2 players mod. The setup was not easy with 2 TV CRT , 2 PSX but so great.

I still have this cable in fact haha

[craycraylj]

I would also like to see this added. A few more link games are Armored Core series, Command & Conquer series,Dune 2000, Doom series, Blast radius, maybe Quake series(Dont remember if that one does or not), and more that I can not presently recall. My friends and family used to link up frequently. Do any PS emulators presently support this?

[Telemachus]

Yeah it is odd that this isn't supported yet, There are quite a lot of games that supported it.

https://en.wikipedia.org/wiki/PlayStation_Link_Cable

I guess the question is how do you link two Mister FPGA's in a lag free way. I doubt we'll see two instances of PS1 core running side by side on one device supporting the link cable. Although that would be cool to see one day too. Maybe with a bigger FPGA.

[jordi]

Yeah it is odd that this isn't supported yet, There are quite a lot of games that supported it.

https://en.wikipedia.org/wiki/PlayStation_Link_Cable

I guess the question is how do you link two Mister FPGA's in a lag free way. I doubt we'll see two instances of PS1 core running side by side on one device supporting the link cable. Although that would be cool to see one day too. Maybe with a bigger FPGA.

It might work by LAN? Not the original, but a network based simulation

[Jahreeva]

I’ve done a little bit more diving into the link cable. Officially it ran as serial IO connection between the two consoles. What would the chances of running it over the usb bus as there is a UART to usb on the main board? I know this may well be massively far down the list of priorities for the psx core but looking through the list of supported titles I would love to give this a go. (Just seen the twisted metal 3 is on the list and that would mean a weekend of carnage.)

[Telemachus]

Perhaps it is something that could be added to a SNAC adapter?

[blacklistedcard]

Yeah it is odd that this isn't supported yet, There are quite a lot of games that supported it.

https://en.wikipedia.org/wiki/PlayStation_Link_Cable

I guess the question is how do you link two Mister FPGA's in a lag free way. I doubt we'll see two instances of PS1 core running side by side on one device supporting the link cable. Although that would be cool to see one day too. Maybe with a bigger FPGA.

It might work by LAN? Not the original, but a network based simulation

It would be really nice to have the connection over the Internet. That would be cool.

[Malor]

IIUC from reading the comments here, if the real PS1 used a connection other than the controller ports for the link cable, it's probably not going to run down the SNAC on the Mister. That's committed to running PS1 controllers and memory cards. A different port on real hardware would probably require a different virtual port.

If there's room on the FPGA, they might be able to haul in the serial port code from other cores, and then run it over TCP or UDP to another Mister. I think almost all the heavy lifting is on the Linux side, and AFAIK that code is complete. It seems likely to be a tiny circuit on the FPGA side, so there might be room.

If it runs down a controller port, though, that might get real messy.

[FPGAzumSpass]

Due to the serial connection, it needs super low lag, so only direct connection via IO pins is possible. Would require either pin switching at runtime for the Controller SNAC or even a special build.
If you only want to connect two De10-nano and not De10-nano + real psx, you can get away with 2 pins only. But still, there is no standard way to have that, you need a special cable or flying wires.

The effort to add the logic is likely not very high, given that the register interface and communication is about the same as for controllers and Blue1 already implemented that.

That all being said: i'm not really interested in doing it. It's still way too much work overall for the niche use case and i would never use it myself.

2 PSX in one FPGA might be more interesting and comfortable, but that is not feasible with the de10-nano. Maybe some day in the future.

[LamerDeluxe]

Is the UART port directly connected to the FPGA?

[Telemachus]

Due to the serial connection, it needs super low lag, so only direct connection via IO pins is possible. Would require either pin switching at runtime for the Controller SNAC or even a special build.
If you only want to connect two De10-nano and not De10-nano + real psx, you can get away with 2 pins only. But still, there is no standard way to have that, you need a special cable or flying wires.

The effort to add the logic is likely not very high, given that the register interface and communication is about the same as for controllers and Blue1 already implemented that.

That all being said: i'm not really interested in doing it. It's still way too much work overall for the niche use case and i would never use it myself.

2 PSX in one FPGA might be more interesting and comfortable, but that is not feasible with the de10-nano. Maybe some day in the future.

Thanks for the explanation and reasoning. Although otherwise a disappointing trend in hardware/feature incomplete cores sadly.

[FPGAzumSpass]

If you think it is, you can change that:

• you tell me which pins you want to use and make a plan how to integrate it with the existing controller SNAC
• i build you a core with the feature integrated
• you build the cable
• you connect it to a second de10-nano and/or real psx and test it with a bunch of games that support it
• you debug with oscilloscope and/or signaltap if it doesn't work
• you test all new releases again if it broke

I'm serious about that: if you really think it's worth it for you, that's the way and we can do it. But please don't expect me to do all this alone.

I understand that for some this is kind of preservation, but honestly, preservation doesn't work if it's not easy to use, because then it will not be used and will break anyway again after short time.
Niche things that are difficult to use, like this serial connection, are very likely to suffer from such a problem.

[Jingsing]

It's not an actual serial link cable but the PS1Digital supports this via wifi.

" PS1Digital will expand upon that functionality by doubling as a wireless Serial I/O Port. Considering that the PS1Digital replaces the PSX’s Serial I/O Port with an HDMI connector, this is a relief for users that enjoyed the Link Cable multiplayer features"