gc-forever - Gamecube/Wii Forums

Recently someone made another thread about some game not running properly through SD Gecko, and grumpy hacktivist/homebrew developer and celebrity tueidj made another sarcastic post:

tueidj wrote:Build your own combination USB/SD gecko that doesn't suck, you know you want to.

Soon, good guy emu_kidid replied

emu_kidid wrote:I know I want to and it shouldn't be too hard to do but I'd need to learn hardware pretty much from scratch at this point.

So now I ask:
Is there any existing homebrew that doesn't use PIO for SD Gecko? I don't remember any.
Is there even any proof-of-concept code for that?

The code is easy, having hardware that uses the EXI interrupt line is what's missing. Somebody made some prototypes a few years ago but it never went further.

Ah, so it is impossible with a simple 'straight through' memory card to SD adapter...
We're gonna need an SD Gecko v2.

Just to be clear the interrupt line isn't necessary for DMA transfers, but without it you need to poll to check if the transfer has finished so it's still basically PIO.
For USB gecko, even if it supported interrupts DMA would be practically unusable since the send/receive/flash write/flash read commands only support one byte at a time.