MiSTer FPGA Forum

Sigismond0 wrote: ↑Tue Mar 01, 2022 11:00 pm I'm not aware of any commercial ones, though I think I've seen people say they've wired their own SNAC port directly into the GPIO pins. I can't be of any specific help there, and unless you can find someone that's done it do provide details, you'd have to reverse engineer a solution from the IO board PCBA design.

Bren McGuire wrote: ↑Tue Mar 01, 2022 11:54 pm what if I connect the 4 pins from the GPIO

In case someone knowledgeable on this topic will read this: what if I connect the 4 pins from the GPIO to a USB 3.0 port as shown in the picture? I'm not sure about that lone trace with the question mark though.

amstan wrote: ↑Wed Mar 02, 2022 2:13 am If I were you and wanted to keep this spartan, I would buy a USB3.0 breakout board with some header wires.

amstan wrote: ↑Wed Mar 02, 2022 2:13 am You're missing the other side of the board, perhaps open the main layout/schematic file in the appropriate software.

C-R-T wrote: ↑Wed Mar 02, 2022 7:28 pm Look at the schematic instead of the layout. It’s on GitHub and can be opened on the Altium online viewer website.

amstan wrote: ↑Thu Mar 03, 2022 4:41 pm Based on your hesitance to look at the schematic (or parse what the RN does) I'd say you probably want to use a normal IO board instead.

Those 100ohm series resistors are probably for signal integrity in order to minimize reflections (or perhaps to lower potential current leaks?). You're also missing the last pin, it's probably just GND, but in the layout it might nto be immediatelly apparent. I also see there's 10k pullups on all the signals.

Yes, what you want to do is probably doable, but not with understanding how to do it and what the implications would be.

Bren McGuire wrote: ↑Thu Mar 03, 2022 5:00 pm Aside from that, the other reason why I didn't want to get an IO board is the Saturn/PS1 cores: if they'll end up needing the extra RAM won't I have to remove the IO board anyways? In this case I'll be back to square one.

amstan wrote: ↑Thu Mar 03, 2022 5:33 pm Wouldn't those same pins be not be available because they go to the ram now? I don't think you can have your cake and eat it too.

rhester72 wrote: ↑Fri Mar 04, 2022 2:22 am a) Yes, you can wire directly to the DE10-Nano. I can provide a map from the USB port to the user I/O pins if needed.

Bren McGuire wrote: ↑Tue Mar 08, 2022 6:59 am

rhester72 wrote: ↑Fri Mar 04, 2022 2:22 am a) Yes, you can wire directly to the DE10-Nano. I can provide a map from the USB port to the user I/O pins if needed.

That'd be great, thank you. Sorry for the delayed reply, I didn't realize there were new messages.

Color		USB	I/O	Signal
-----		---	---	------
RED		1	N/C	+5V
WHITE		2	2	TX (MIDI out)
GREEN		3	1	I2C SDA
BLACK		4	4	GND (common)
PURPLE		5	8	I2S DAT
ORANGE		6	7	I2S BCLK
drain		7	6	I2C SCL
BLUE		8	5	I2S WS
YELLOW		9	10	RX (MIDI in) [controlled by IO6 on newest boards]

rhester72 wrote: ↑Sat Mar 12, 2022 10:24 pm

Bren McGuire wrote: ↑Tue Mar 08, 2022 6:59 am

rhester72 wrote: ↑Fri Mar 04, 2022 2:22 am a) Yes, you can wire directly to the DE10-Nano. I can provide a map from the USB port to the user I/O pins if needed.

That'd be great, thank you. Sorry for the delayed reply, I didn't realize there were new messages.

Sorry for my delay as well - been working on a few things.

rhester72 wrote: ↑Wed Mar 16, 2022 4:13 am re: power - yes, you'll definitely need to source +5V. It should be available on the Arduino rail on the other side of the board from the user port.

re: pinouts - to be honest, I'm not 100% certain (it bothers me that our bundles are reversed), but you're right in that mine is 'mirrored' because I was actually working from a male cable end. That being said, there's only four possible combinations to try (RX +/- and TX +/- pairs flipped both ways), so a 6-button Genesis controller (original old-school, not Retrobits!) and a SNAC adapter plus some Duponts should answer that question safely (since they are only data lines).

EDIT: A male cable end because it was plugged into the I/O board at the time of testing, and a Genesis specifically because it's the only one to use all 7 available I/O lines for testing - that plus the 240p test suite (attached) will give you 100% confidence your wiring is correct.

rhester72 wrote: ↑Tue Mar 22, 2022 9:02 pm I don't want to discount the importance of resistors, but I will say that at least a couple of folks have directly wired Pi pins straight to P7 without obvious issue in the past, I can't imagine SNAC would be much different.