gcvideo - Open source GameCube component cable solution

Linear voltage regulator in an enclosed space with no heat sink seems like a bad idea.

Have you tested how much heat is given off?

 

Totally agree. Seems like a potential overheating issue. Maybe replace it with a Switching Regulator Module. Though they cost much more than the old linears.

 

How much dissipated power (in mW) would you consider problematic? Switching regulators are not 100% efficient and to a first-order approximation you can assume that all of its output power is converted to heat by the FPGA.

 

Power Dissipation

As this is an engineering problem I am going to use some maths (instead of guessing) to show you guys that the 1.2vreg will never get hot enough to require a heat sink. So to start lets define the upper and lower power dissipation requirements.

Upper bounding limit

If we look at the datasheet for the 1.2vreg (MCP1827S)

http://www.farnell.com/datasheets/456104.pdf

Page 21 (section 5.3.1.3) shows that maximum power that can be dissipated at 60C (140F) is 2.218W for the T0-220-5 and 2.083W for the DDPAK-5 lets choose the weaker one 2.083W and round it down to 2W as we want the worst case. There is no way we want to be running that close to the maximum limit of the devices power dissipation lets use 80% of that value so 2W * 0.8 = 1.6W. We are saying here is that with the gamecubes enclosure at 60C (140F) we don’t want the device to dissipate more then 1.6W. Which is still very hot in practice we don’t want to be near this wattage level at all but the device will run at this level without getting damaged so let this be are upper limit.

In terms of current flow through the device this will be I = P / V = 1.6W / (3.3V – 1.2V) = 761mA @ 60C

Lower bounding limit

For the lower bounding limit we need to make sure that that regulator still regulates the voltage currently if we don’t pull enough power the regulator will see an open circuit and the 1.2v output may drift up or down. Looking at the datasheet I can’t see a minimum load regulation current but all the load regulation graphs stop at 1mA so I will choose that as the lower bounding limit. Which gives as a minimum power dissipation requirement of P = IV = 1mA * (3.3V – 1.2V) = 2.1mW

Heat sink requirement

To not use a heat sink we want to be well away from 761mA upper limit I would say you want to be at around a quarter of that level and below so your device will be warm but not hot so we are looking for a maximum current through the device of 761mA / 4 = 190mA @ 60C.

Measured current flowing through the 1.2vreg

I measured 25.5mA flowing through the 1.2vreg on a V2 board with an xc3s50a fitted so well below 190mA and above the lower limit of 1mA.

Actual testing

With a V3 board fitted inside the cube I removed all the screws holding down the top of the case so I could get to the 1.2v regulator quickly after power off. I then ran the gamecube for 4 hours playing Mario kart double dash and then powered off the cube and quickly removed the casing. I don’t have a temperature sensor so I used my finger it don’t feel hot actually it was the same ambient temperature of the enclosure ie I cant feel any difference between the 1.2vreg and the gamecubes PCB.

 

A "yes" would have sufficed.

 

True, but people do their diligence around here. I'm thankful that people take the time to write up comprehensive answers "why?". I've picked up a lot of electrical engineering knowledge from posts like these.

 

Sorry, I was very much thinking about it from "I asked the question, I don't need the theory" point of view. I could have worked it out myself if I have the current numbers etc, but was just asking if it had been done.

But yes, you are quite right - its handy for people to read and gain knowledge from.

 

I just saw the Shuriken board a month ago on the net and have been researching it and want to take a leap and make one of these. Since I noticed that multiple forums are discussing the Shuriken mod and that this seems to be the most technical of the boards I have found, I thought I would ask some questions to confirm my understanding of how to make this and to summarise the state that the project is currently up to now for others to see. I’m the kind of person who really doesn’t want to fry their cube (as it is fully original and in good condition) and I don’t want to make permanent mods to it. I also have some basic soldering experience but am willing to experience ordering the PCBs etc to make one.



My understanding is that v3 is the revision that is open to everyone on the web and that it has been tested by multiple people and that they are quite happy with the results.

When v4 is released, will it be announced with all the files on the webspace.virginmedia website for us to use? I also assume that v4 will not be ‘tested in the wild’ before a full blown release and that it may be safer to use v3 until the v4 release is tested on a larger scale after its release to iron out possible bugs.

Since I want to look into ordering parts for one of these, is there an ETA on v4 and is the only changes from v3 a proper reset / power up IC and plug and play design (with a male connector for the Digital AV port on Gamecube built into the case (as previously shown in this thread) and the contacts as one of the PCBs included in the Shuriken downloads)? I understand (and hope to be corrected) that the reset fix is only required to aid in programming the FPGA and nothing more.

I noticed that GCVideo on Github states it has support for Shuriken Video v3/v4 boards. I take it that this software is more up to date than the one on webspace.virginmedia and that code should be sourced from Github for the latest code for the Shuriken project in the future. Is this right?

The BOM from webspace.virginmediastates that an XC3S50A or XC3S200A can be used. Looking at gc-forever, the XC3S200 supports line doubling whereas the XC3S50A does not, and hence the XC3S200A is the better chip to use as it supports more features (the only downside is that it costs more). Is this correct?

Can the device be unplugged and plugged in while the Gamecube/TV is running without damaging the Gamecube or device? I don’t see why not (besides the risk some people have been discussing about ESD).



With the PCB manufacturing, I have armed myself with KiCAD and used GerbView to import the gerbers from the webspace.virginmedia site into pcbnew so that I could run a DRC with the parameters set by some PCB manufacturers to make sure that the manufacturer wouldn’t have any problems with the gerbers. When I import only the top layer copper, I get issues with almost every bend having too small a trace width (see below, min trace width for DRC set at 0.2mm). I assume that this is just an error with pcbnew/gerbview import and that the gerber is actually compliant. Has anyone who has sent the design to be manufactured had any problems?


I also get errors when opening the drill files in gerbview as excellon drill files, but I assume this is in the same boat as the above and that the files are fine.


Also, is there a recommended thickness for the PCB to be made at? It seems 1.6mm is standard and it probably doesn’t matter too much as it can be held in with glue.

 

I’m the guy that happy_bunny was talking about, and I’m pleased to say that the board is working quite nicely!

I received a populated board (minus the FPGA since you need a special license to ship them abroad) along with a 3D-printed case. The case is a nice touch, and makes it much safer to have than having a bare board stick out of the console. You can either choose the cheaper xc3S50a (which only does 480i), or spend an extra $10 for the xc3S200a (which allows for bob de-interlacing of 480i games if your TV can’t handle 480i). I’d say the xc3S200a is a no brainer, as a lot of TVs apparently cannot do 480i, and while bob de-interlacing isn’t always pretty, it has much lower latency compared to what your TV might do. Make sure you obtain one from a legitimate seller (DigiKey, Mouser, Farnell, etc.), as the ones on AliExpress and eBay tend to not have a traceable procurement procedure, which means you don’t know if the chips were properly stored, or if they are even real!

Install:

Installation is a lot trickier than your typical mod for two reasons: the FPGA soldering requires a fine-point soldering iron (or a reflow oven/hot air with solder paste), and getting the original digital port out is no easy task, as it requires either a good vacuum desoldering station, or a soldering iron with high thermal capacity paired with desoldering braid (Unseen mentioned ChipQuick - a low temperature solder alloy that'll keep the solder liquid for a while so parts can be removed easier - should work too!). There are tons of ground pins on a thick ground plane, which makes this a lot tougher than getting mask ROMs off of NES cartridges

To tackle the FPGA soldering, I used a Metcal iron (at my university) paired with a fine-pitch tip to attach the FPGA on the board. No sweat; just check your connections!

But then came the digital port removal, which was definitely the toughest part, and where I ran into the most problems (disclaimer: I’m not a professional modder and I don’t sell what I’ve soldered!). If you’re going to take it off with a vacuum tool, be warned that the pin diameter is a bit smaller than a typical through-hole pin, so generic tools may have some difficulty. I have the RadioShack desoldering iron, and the tips for those are too wide for this. So, my first thought was to add more solder and flux to the pins so the vacuum would have more to suck up, but what ended up actually happening was the solder was pushed into the pins I already worked on! It also stressed the board too much and ripped some traces on the GC PCB

So what I ended up doing was turning my Weller iron up to 350C and using some desoldering braid to get the rest of the port out. That took care of it without any further casualties, and then I used some AWG 30 wire to bridge the connections to the digital chip. That seemed to fix it, but that was a mess!

Going back to the pin thickness issue, there is actually no commercially-available pin header that will fit where the digital port connector was. What I did was use some breadboard jumper wire heads (by happy_bunny’s suggestion), line up a couple connections to make sure the board was evenly lined up, and solder away. It’s a little tricky at first, but not impossible.

The most important thing to do is check your connections and that you have no shorts! Goes without saying, but it’s a bit more important in this case, as 12V is one of the connections used, and shorting that anywhere on the FPGA or GC data lines will probably fry one, the other, or both.

That’s a bit of a long write-up for the install, but it’s important if you’re thinking about installing this yourself. Make sure you understand the problems aforementioned and that you know how to avoid them (e.g. don’t repeat my mistakes )

Results:

Having never seen a GC in 480p, I am blown away! Metroid Prime looks much crisper, and especially since my TV has terrible de-interlacing, the onboard de-interlacing is a nice touch. My TV also has bad input latency for composite inputs, so this was a breath of fresh air. Definitely going to be playing more GameCube once I’m done with school

Suggested Improvements:

The most obvious issue that I think is worth noting is the board sticks out a fair bit (as other have mentioned), which means the GC needs to be handled a little more carefully when being moved around to not stress the PCB. Not much can be done about that since the FPGA and HDMI port take up 2/3rds of the length, but what I saw that could help is that the digital port has extra ground pins along the sides for added stability, which the Shuriken board could probably benefit from. However, happy_bunny mentioned he glued the case to the GC PCB to add a bit of stability, so that is a valid option too! If you’re willing to modify the GC case, you could add corner braces as well to make it a bit sturdier. What may be the best choice is to use a two-board solution: one board to bring the digital port pins further into the GC, and then use essentially the same board to make the HDMI connector flush with the output. But that’s a whole other thing to work out

This wasn’t really a big deal, but I would move the CONN6 pin closer to the digital port pin-header. This would keep the install a little neater, but then again the case hides it!

A big thanks to happy_bunny for all the help and guidance throughout the install process, as well as the parts!

 

There are special low-temperature solder alloys on the market that are primarily meant for desoldering - you flood the pins with the alloy at your standard soldering temperature so it mixes with the regular solder on the pins and the mixture will stay liquid much longer than standard solder because even after mixing it's melting point is around 100°C or so. ChipQuick has a full kit that includes a small length of such solder alloy, special flux for it (extremely sticky stuff) and some alcohol wipes (to remove that horrible flux) as "SMD1" - despite the name it also works well on through-hole parts like the digital video port, but it's quite expensive.

A single (unplanned) experiment has shown that shorting 12V to an adjacent signal kills both FPGA and GC.

 

I forgot all about ChipQuick! That probably would've helped

 

How's the progress on the potential Wii mod going? I'm trying to decide between waiting for that or getting one of those cheap HDMI adapters. Do you have any idea if the mod would look noticeably better than an adapter? Thanks for your hard work.

 

You mean this?


Which was barely good enough to capture this?


If you look closely, you can see that the resolution popup was flickering between two values - I don't know yet if this is due to signal quality problems or if the code misdetects the Wii's resolution. I'll know more once I've built a more reliable connection between the Wii and the FPGA board.

A cheap HDMI adapter has a few advantages - it's cheap, it's available right now and it's a plug-and-play solution. Wiring GCVideo to the Wii's internal video bus requires some rather fiddly soldering either on a set of microvias or on the 0.5mm-pitch pins of the AV encoder.

I have never used any of these adapters, so I don't know about their quality.

 

Hi unseen, I'm a huge fan of what you've accomplished, I just finished installing gcvideo on my gamecube, and was hoping to move it to the wii, like you have already. Would you be able to solve the signal confusion problems by cutting up a gamecube motherboard for the digital output and existing AVE chip, and attach that to the inputs of the wii's AVE chip? I have been having trouble finding schematics on the input sides of these chips, but I thought you might have some insight into how similar they are. Thanks -OnePunch

Gamecube-motherboard-pins-edited by OnePunch posted Jun 30, 2016 at 7:09 PM

 

No.

The Wii's encoder chip handles both audio and video and has some configuration registers that can be set from the Wii's CPU - I don't know what they are actually used for, ignoring them and just processing video and audio data blindly seems to work fine on my test setup.

 

So you were able to get the GUI from the FPGA board working as well? I am interested in this as a way to get Project M lag-less on an HD tv. If you have any other ideas I would love to hear those too. Thanks for the insight

 

Yes

But is your HD tv lag-less with 480p input signals over HDMI?

 

That's great to hear! Is there a diagram out there yet for matching the wii outputs to the FPGA?

It has 5ms of lag advertised, and the game is 60fps, so it's underneath one frame of lag. I have melee running with the FPGA board and none of the top players in my area say it plays any differently.

 

The various gcvideo projects in flight look very promising. I've seen one that utilizes HDMI and another that utilizes the Wii component cable but... ...is anyone aware of a project that decodes what I'm assuming is the YCbCr back into RGB so that the RGB pins on the multi-out connector can be reconnected? That would be my ideal solution since it'd let me use a SCART cable and I'm really hoping someone goes this route so I can have NES/SNES/N64/Gamecube all running through the same SCART switch. Thank you!

 

A YPbPr to RGB circuit is doable of course (you'd also want some kind of switch to keep the component).
It's unlikely there's a project to convert the Wii digital video into RGB.