Gamecube Digital port

[Darkman]

Hello,

Just curious, but is there any use for the Digital A/V port on a european PAL Gamecube? I mean for video purposes, like VGA or progressive scan output. If not, then why did Nintendo include it anyway?

D.

[NFG]

Digital audio and non-progressive component are both available through this port.

[Cyber Axe]

rather anicent post now however i am curious about the digital audio out on the port

from one site i read that the audio is DAI however i cant find any info on this even DAI itself seems to be hard to find cant even find pictures of ht econnection it uses

and thers aparently a DAI to S/PDIF mod though info seems to be hard to find

[NFG]

There's an AtariLabs forum post on the subject, sorry but I haven't got the link handy.

Found the link.  Here's the chip pinout, courtesy of Oscar on the AtariLabs forum (Which is DEAD DEAD DEAD, dammit, why does it allow new posts!?)

In this method, if you want to use VGA, you need progressive GCN software. This will work like as Transcoder method. Non-progressive mode, GCN will output 15Khz interlaced signal.(NTSC mode)

Well,you need "Componet Cable" for GCN. In cable's connector(GCN side) there is a strange chip inside. That is D/A Converter. All pin assignments are...

Pin Assign of CMPV-DOL D/A Chip

[1�`4] DATA
[5] 3.3V
[6�`10] DATA
[11] CLK(50MHz)
[12] GND
[13,14] 1.2V Compensation or Filter??
[15] R-Y
[16] GND
[17] B-Y
[18] 3.3V
[19] Y
[20] SENS? (maybe connected to Japanese D Connector)
[21] Hsync
[22] Vsync
[23,24] GND

Pin #12 is switch for Component/RGB mode. You need desoldering that pin and pull up to 3.3V. In that conncector, connector Pin#1 is 3.3V. User 10k ohm to pull up, that may be enough.
Then, you need connect some conntector to output. Y will become G, BY and BY to B, RT to R.
At this RGB mode, sync signal will not on Green. So you need connect H and V sync directly from D/A converter. That D/A have separate sync on Pin #21 and #22.

Thats all.

[Hojo_Norem]

rather anicent post now however i am curious about the digital audio out on the port

from one site i read that the audio is DAI however i cant find any info on this even DAI itself seems to be hard to find cant even find pictures of ht econnection it uses

and thers aparently a DAI to S/PDIF mod though info seems to be hard to find

Technicaly the SNES s/pdif mod is a DAI to s/pdif mod.  The SNES APU outputs a DAI signal to the DAC where the cartridge audio is mixed in before passing thrugh to the A/V port.  The main differenct between the SNES mod and the GC is that the SNES APU provides a clock signal while the GC need a external clock for the audio.

However, I do not claim that this is correct, rather what I have concluded from performing the SNES s/pdif mod and reading the various forum postings about the GC's digital port.


EDIT: My 64th post, my favorite number! ^_^

[Aidan]

Lets ditch the term DAI, as it has fairly little meaning beyond indicating that there's a digital representation of audio somewhere. It certainly does not describe the format of the data. (DAI include S/PDIF, AES3, AES3_SMPTE, I2S and so on)

The SNES used a standard I2S bus between the APU and the DAC. As I2S has been a standard used for transmitting audio for a rather long time (albeit inside a device rather than externally), the mod is fairly easy.

As far as clocking on the GC goes, it shouldn't need an external clock (external clocks make internal synchronisation a lot more difficult, especially where things like DMA happen). It looks to use something similar to I2S, so the same basic circuit that the SNES uses could well be applicable to the GC. However, I don't know how the data format that the GC spits out. (It could be 16bit, it could be 20bit, it could be 24bit. If it's less than 24bits, is it left justified or right justified?).

Basically, the GC digital audio interface looks like they've just tapped off the lines that go to the GC's internal DAC. That means that the LR clock indicates if the sample is for the left or right channel, the bit clock actually clocks the bits into the converter, and the data line actually carries the data.