Me: I have this project idea: #WIFI Game Boy Cartridge - I was a bit naive when I started this, tried to toggle pin for pin but it was way too slow. Would/could this work with the I2S parallel interface? I wasn't able to find much on the I2S interface when I started this and what I found was above my skill set, but I still like the idea of having a cartridge that has wifi.

Sprite_tm says:4:31 PM
Ah, I saw that. Did something like that on a Vectrex with a CortexM4.

Sprite_tm says:4:32 PM
Wrt the WiFi GB cartridge: Long story short, I don't thing I2S is the right way to go there.

Me: okay, any right ways?

Sprite_tm says:4:33 PM
The issue mostly is that you need to see that a CS line goes low, then immediately read the address lines, look up whatever you want to send back and send it.

Sprite_tm says:4:34 PM
I think that I2S would be too slow for that; you'd have to set up a transaction and everything. I think you could get it to work if you wrote a high-prio interrupt for the CS pin, then in the interrupt handler, in assembly, read the address GPIOs as fast as you can, grab a response from internal memory (which luckily you have more than enough of) and send that to the data pins.

Sprite_tm says:4:35 PM
If you need help with that, poke me; by now I have some experience with high-level interrupts and I'm actually curious if the ESP32 can do it, but don't really have any interesting consoles here.

Me: I thought "as fast as I can" would be I2S, since there's no way of getting pins parallel

Sprite_tm says:4:37 PM
You might get it to work... but there's a fair amount of setup using the I2S peripheral. It may still be quicker than doing it manually, I agree.

Sprite_tm says:4:39 PM
@davedarko Maybe a good idea to move on to other qs... if there is still time at the end, I'd love to come back to it. For now, feel free to poke me at [mail] for this.