Cloning the Gamecube component cable

[darcagn]

I relocated the capacitor... great fit! Booted up the GameCube to make sure it still works and it indeed does.

It's not mounted or anything, this is just a crude stuffing it in and shutting the case... didn't even cut the drive cage or anything. I won't have any time to actually properly mount it until Thursday, but I'll get that taken care of then.

I bought this Ultra Slim HDMI cable from Monoprice, which I think will be small enough to fit into the existing hole in the plastic case. My measurement is that the hole in the case is 3/8" thick, and the Monoprice cable says it's 1/4" thick.

Either way it should definitely be possible to fit this without cutting the GameCube up.

[bobrocks95]

Awesome! Can we get some pics of your moved capacitor when you open it back up? I don't really know what that entails so it would be informative for sure.

Are you going to add an optical output as well?

[darcagn]

Yep, I just ordered some of the Everlight PLT133/T9 which should work and are panel mount with one screw to hold to the panel.

As far as removing the capacitor goes, it's just a matter of desoldering the two legs from the motherboard. It's surface-mounted so it shouldn't be difficult to do, just make sure you don't heat up the pads too much and pull them off of the board. Then just run wires from the two pads where the capacitor was to the legs of the capacitor, and put some tape around it and stick it somewhere behind the analog AV connector. Pretty easy, anyone who is able to do the mod should be able to do that.

[lev11]

Looks good, and probably worth moving the capacitor in time saving alone versus measuring, cutting and edge finishing the case and metal shield.

The spacers I used were 15mm, you might want to grab some flat washers too to fine tune the height of the spacer and get the port in the middle of the opening.
The local supplier didn't stock below M4, so the screws I got were from here: http://cpc.farnell.com/unbranded/nscm02 ... dp/FN02938
With them being plastic I just nipped off the excess length with some side cutters once in place.

[lev11]

Unseen, does your cheapo USB spdif card get an occasional hiccup, like this, about 16seconds in: https://app.box.com/s/glswjsordlpd4fajrx08piuz7ib3dbez

Seems to occur at a regular frequency, about once a minute. Same on original gamecube games as that emulator example, but its not PC related as it doesn't occur on my TV's spdif out. Possibly unique to these Cmedia cards as it certainly doesn't happen on my AV amp.

[Unseen]

Unseen, does your cheapo USB spdif card get an occasional hiccup, like this, about 16seconds in: https://app.box.com/s/glswjsordlpd4fajrx08piuz7ib3dbez

Seems to occur at a regular frequency, about once a minute. Same on original gamecube games as that emulator example, but its not PC related as it doesn't occur on my TV's spdif out. Possibly unique to these Cmedia cards as it certainly doesn't happen on my AV amp.

After listening to various recordings of the soothing main menu sound of the Gamecube I can tell you with high confidence that... I'm not sure. I do not get artifacts like the one in your clip, but a five minute recording using Reaper had some clicks in it after ~2.5 minutes. Another five minute recording using Sound Forge didn't seem to have any problems, same with Audacity. I still need to re-run these tests using the Line In of the card to make sure that it really is an SPDIF problem and not just a general problem of the card.

Could you retry the recording using the card's line in instead of SPDIF to make sure that we're not chasing the wrong problem?

If it's really regular for you, the problem might be caused by the non-standard sample rate of the Gamecube (48042.7 Hz), but the difference is less than 0.1% and I think I've read somewhere that consumer SPDIF is allowed to be off by up to 1%. I could "fix" that in the FPGA by dropping every 1125th sample, but I'm not sure what effect this would have on the audio quality.

[darcagn]

Got the Monoprice HDMI cable in today. As expected, it fits in the hole very well. I'm extremely impressed with this HDMI cable; I cannot believe how tiny it is.

Spoiler

It's been hard for me to find nylon M2 screws anywhere locally or shipping from the USA, so I'll probably have to order a bunch of shit from China. In the mean time, I want to play my GameCube and thus wanted to close the case, since it'll probably take at least a week and a half for crap to come in from China. Using a little bit of tape, hot glue, and cut-out cardboard, I added enough bulk to the FPGA board so that when you close the drive cage over it, it's very snug and doesn't move around much even when you plug/unplug the HDMI cable. I wouldn't want to leave it like this permanently, but it should be OK for right now.

I'm very happy with the way it turned out, and I'll be getting my game on until the nylon screws and S/PDIF transmitters come in, at which point I'll update the FPGA to the 1.3 firmware, add optical audio, and firmly mount it to the drive cage.

Spoiler

[CkRtech]

It's been hard for me to find nylon M2 screws anywhere locally or shipping from the USA

Have you tried contacting the guys at boltdepot.com? I have ordered all of my specialty stuff from them, but I haven't seen nylon M2 screws. Perhaps just asking them will help steer you in the right direction.

[darcagn]

It's been hard for me to find nylon M2 screws anywhere locally or shipping from the USA

Have you tried contacting the guys at boltdepot.com? I have ordered all of my specialty stuff from them, but I haven't seen nylon M2 screws. Perhaps just asking them will help steer you in the right direction.

Thanks for the link! That site looks great. I think I can actually make do with the products that they offer there. I've placed an order and I'll let you guys know how it turns out.

[CkRtech]

Thanks for the link! That site looks great. I think I can actually make do with the products that they offer there. I've placed an order and I'll let you guys know how it turns out.

Excellent! Good luck!

[lev11]

@Unseen I'm using foobar2000, but the issue occurs just by selecting 'listen to this device' in the windows recording device options without running any capture software. I've retried and yes its reliably frequent for me ~60seconds. And no it doesn't occur on the line input. No audio and no noise though, but I guess with digital audio nothing really is nothing, so if I run Artemio's 240p test suite and do the sound test, pressing A until the artifacts start they then stop as soon as I stop. I wouldn't worry about fixing this if it risks audio issues in normal devices as it sounds great on my av amp, this USB card was only for messing about anyway. And yes that main menu sound is soothing, I think I'll grab a copy of it for my morning alarm.


@darcagn I was going to suggest there must be an imperial equivalent, just don't go too much bigger than M2, not sure what KNJN advise the actual hole size is but M2.5 wouldn't fit through. Have you ran any emulator software yet, such as FCE Ultra GX or Snes9x GX? It looks like they both linedouble the 240p content, so when adding scanlines with GC-Video the results are really good.

[BazookaBen]

And yes that main menu sound is soothing, I think I'll grab a copy of it for my morning alarm.

You guys know that is actually the Famicom Disk System music slowed down ~16 times?

https://youtu.be/rjEsXf3SJ6o

[lev11]

That is cool!

[Ed Oscuro]

And yes that main menu sound is soothing, I think I'll grab a copy of it for my morning alarm.

You guys know that is actually the Famicom Disk System music slowed down ~16 times?

https://youtu.be/rjEsXf3SJ6o

Not exactly:
https://www.youtube.com/watch?v=u1m6j38CDOc

Holy shit tho: I never realized that 8 bits = 16 (times slowed down, which isn't multiplying but hey) = 128 bits

Bit depth doesn't matter but somebody was really clever there.

Always loved the GameCube menu music - so soothing and gentle after the years of bombastic THIS IS PLAYSTATION, BITCH opening, Sony's own version of the THX aural cannonade.

[CkRtech]

THIS IS PLAYSTATION, BITCH opening, Sony's own version of the THX aural cannonade.

I don't know if you got a PS3 early on, but that opening used to be the current volume x 3. I was really happy when they released newer firmware to lower that volume.

[Ed Oscuro]

I mean the very original PlayStation boot screen. Don't remember what the PS3 opening is like.

[ApolloBoy]

Don't remember what the PS3 opening is like.

It sounds like an orchestra warming up: https://youtu.be/GUb1gIKhwMU

[panzeroceania]

@Unseen

you've mentioned that the digital audio the gamecube produces isn't a common frequency that could be simply converted to SPDIF without altering the signal to make it standard compliant. This is true of a lot of console's internal console's I2S frequency. wouldn't it be possibly to bypass SPDIF standards entirely and simply get a DAC that accepts I2S and generate an analog audio signal without touching the console's native audio frequency?

If so, which DACs would be the ones to do the job?

[Edward_Tz]

So is anyone making a board for the component output that I can order?

[Unseen]

you've mentioned that the digital audio the gamecube produces isn't a common frequency that could be simply converted to SPDIF without altering the signal to make it standard compliant.

It's 48042 Hz instead of the usual 48000 Hz, but as far as I can tell this is still within the allowed tolerances. "Normal" clock accuracy in SPDIF specifies that the sampling frequency should be within 1000ppm of the nominal value, the difference for the Gamecube is 875ppm.

This is true of a lot of console's internal console's I2S frequency.

I think most of them have a much larger difference, the situation on the Cube was likely caused by an off-by-one error when the chips were designed.

wouldn't it be possibly to bypass SPDIF standards entirely and simply get a DAC that accepts I2S and generate an analog audio signal without touching the console's native audio frequency?

I think you will find that most consoles already have some kind of DAC internally that generates an analog audio signal. ;) Why would you want to add another DAC?

If you want to add a digital audio output to a console that uses "weird" sample rates but has digital audio available internally, you could try to solve the problem with a sample rate conversion chip. TI has a few, for example the SRC4190 or SRC4382, but I have no experience with them except for looking at the summary page of the datasheet.

[BONKERS]

So is anyone making a board for the component output that I can order?

Ditto. i'd love to have a reasonably priced Component cable

[Bobster]

So is anyone making a board for the component output that I can order?

Ditto. i'd love to have a reasonably priced Component cable

megalomaniac on the GC-forever site has been hinting at a possible plug and play version. Of course people get busy so we just have to be patient .

http://www.gc-forever.com/forums/viewto ... 216#p30487

[Edward_Tz]

Making the chip is beyond my capability. Fine with a bit of soldering being needed. Plug and play would be great too.

Good to hear though. Now if swiss could just get better compatibility. I'd order a wasp from him too.

[Woozle]

So I would love to tackle this mod over the summer. Any recommendations on a good FPGA to use? I would like one that is slight overkill to allow for future updates to the HDL. I have a crappy Xilinx Basys2 (spartan 3) which I used for my lab class, but I'm sure something a little more capable would be best.

Would something like this work? I saw it posted earlier http://www.scarabhardware.com/product/minisp6/
or would the recommended pluto be fine http://www.knjn.com/ShopBoards_RS232_Parallel.html ?

My budget for the FPGA is ~$150. I don't mind it being a unit external to the gamecube but from my understanding certain clock lines make a distant box difficult.

[dylanlip]

Has there been a definitive (or at least usable) digital audio mod for people who just need that and not video? I'm already good with D-Terminal out to a Lumagen, and now would just like either TOSLINK or Coax from the system (Not from the cable like GamesX suggests), which some users from various forums have seem to have accomplished (Without real/specific detail though). I've heard mention of a MegAUDIO board from Megalomaniac that's been produced, but all I've seen on his shop for many months now is just his MEGAdrive.

[bobrocks95]

So I would love to tackle this mod over the summer. Any recommendations on a good FPGA to use? I would like one that is slight overkill to allow for future updates to the HDL. I have a crappy Xilinx Basys2 (spartan 3) which I used for my lab class, but I'm sure something a little more capable would be best.

Would something like this work? I saw it posted earlier http://www.scarabhardware.com/product/minisp6/
or would the recommended pluto be fine http://www.knjn.com/ShopBoards_RS232_Parallel.html ?

My budget for the FPGA is ~$150. I don't mind it being a unit external to the gamecube but from my understanding certain clock lines make a distant box difficult.

I looked into the MiniSpartan and it looks nice, but I decided I wanted the board to fit inside the cube and disregarded it. The main advantage would be having a flasher built-in if you don't already have one (which you probably do or have access to your lab to flash it anyway). I don't think Unseen is going to add anything that needs a more powerful FPGA in the future. Could always be pleasantly wrong though.

Has there been a definitive (or at least usable) digital audio mod for people who just need that and not video? I'm already good with D-Terminal out to a Lumagen, and now would just like either TOSLINK or Coax from the system (Not from the cable like GamesX suggests), which some users from various forums have seem to have accomplished (Without real/specific detail though). I've heard mention of a MegAUDIO board from Megalomaniac that's been produced, but all I've seen on his shop for many months now is just his MEGAdrive.

AFAIK to get digital audio you need the MX chip in some regard. So either from within your cable, reverse engineered by an FPGA like this project, or as I believe Megalomaniac did it, with a salvaged MX chip on a separate board. As a note nobody in China has any MX chips anymore, and Megalomaniac doesn't make any of the Mega boards anymore that used them.

[Unseen]

I don't think Unseen is going to add anything that needs a more powerful FPGA in the future. Could always be pleasantly wrong though.

I don't think so either, but I'm not yet sure how much space "Enhanced DVI with Audio" will need (*). Of course the plan is to attempt to shrink the existing parts of the design first when the space runs out.

(*) If it ever gets finished - last weekend I found out that my current code for pushing out data frames works great in simulation, but appears to get mis-synthesized. Re-timing all of it is annoying, but it will be a nice opportunity to slice up the current mess into smaller, hopefully more efficient parts.

AFAIK to get digital audio you need the MX chip in some regard.

No, there are old SPDIF "mods" that just connect a Toshiba chip (obsolete by now) to the digital audio signals. It shouldn't be too hard to extract the audio-to-SPDIF parts of GCVideo Lite (slightly simpler than the one in DVI) and design a board just for audio. The functionality probably fits into a CPLD instead of an FPGA, although I'm not sure how big (=expensive) the chip would need to be.

[Woozle]

I looked into the MiniSpartan and it looks nice, but I decided I wanted the board to fit inside the cube and disregarded it. The main advantage would be having a flasher built-in if you don't already have one (which you probably do or have access to your lab to flash it anyway). I don't think Unseen is going to add anything that needs a more powerful FPGA in the future. Could always be pleasantly wrong though.

Not having a flasher isn't an issue for me, so I guess the pluto will work out. Soon I'll have a virtex7 board on loan...but can't use it for recreational purposes :/ Thanks for the reply.

I'll order the pluto fpga towards the end of July and tackle the mod then. Thanks for the awesome work Unseen, it's very motivating and inspiring. I hope one day I can apply FPGA work towards helping the gaming community like you do.

edit: Ordered the pluto FPGA board and will be installing mod next week (7/27/15), any tips are greatly appreciated!

[darcagn]

So I haven't messed with this project in a while; haven't finished mounting the hardware or setting up the digital audio.

However I did purchase this HDMI to Component converter to connect the GameCube up to my 14" Sony BVM CRT monitor.

Good news: this adapter handles 240p over HDMI, making this a great way to play GameBoy titles on a CRT

Bad news: there appears to be some sort of color issues going on on all games and all video modes. Hard to describe, but things on the screen have black pixels around them. sometimes green pixels pop as well.

Here's a video of it: https://www.youtube.com/watch?v=R4ynHk-5FNI

toggling the RGB limited range setting makes it better/worse but doesn't fix it.


I tested the converter on an LCD screen and the same thing happens so it's not the CRT display. I also tested out a FireTV stick as the HDMI source and there were no problems converting that.

[BazookaBen]

Maybe you'd have better luck with a HD Fury 2 or 3:

http://www.hdfury.com/component-displays/