gcvideo - Open source GameCube component cable solution

Where is your web page?

 

So you just need to program the flash and that will program the FPGA? If so that would be a simple task with my programmer. I might offer these here if it's ok with happy_bunny once everything is finalized and the programming is something I can do.

 

I dont mind its all open source so do with it what you want just dont blame me if it dont work! Unseen kindly updated the fpga pinout for v3

https://github.com/ikorb/gcvideo/tree/master/HDL/gcvideo_dvi/bin

I had to move pad snoop for v3 its now located on pin 73 and spdif is on pin 72 (which go to pins 1 & 2 on conn6)

 

The FPGA is RAM-based (like most current FPGAs on the market), it automatically loads its configuration from the external flash on powerup.

 

Cool beans, so no need to worry about how to program the FPGA and just the flash.

 

how would you program the flash ? if you do it off board with a 3d party programmer you will need to convert the top level *.bit file generated into a raw binary file something like this

promgen -spi -p bin -o spi_flash.bin -s 512 -u 0 toplevel_p2xh.bit

then you can just flash the raw file spi_flash.bin with the 3d party programmer. Or If you have a xillinx JTAG programmer you can program *.mcs using iMPACT however the flash and fpga will need to be on the board together and powered up.

whoop new toys got my p'n'p board today



not sure how much its going to stick out though, will find out at the weekend I guess.

 

What does the conn5 connect to? Is that supposed to insert into the Digital Socket?

 

Yup

 

A couple questions: the board in the picture above - do you still have to mod the system for this to work? It's possible to make the board output VGA, right?

 

No system mod required it should just work, currently its dvi / hdmi technically is possable to do VGA but that would require mods to the board and to the vhdl coding.

Not a massive amount to report board built electrically no shorts so it looking good at this point, need to power it up next see if it smokes ;-)

 

Looking really nice, cant wait until its readily available.

 

thanks, no smoke 12v / 3v / 1.2v lines look good so the PCB likes healthy will try and get the bottom half of the case done this week.

 

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.