MiSTer FPGA: Interface pinout

Use this pinout if you'd like to build your own custom MiSTer interface.

The leftmost five columns are for when constructing a USB cable to connect between the user port and a Raspberry Pi.
If you want to connect a DE-10 Nano directly to a Raspberry Pi without an I/O board or USB cable, use the rightmost two columns and refer to your DE-10 Nano's manual for the pin positions.
You can omit some of the connections if you don't want certain features. For example, if you don't want to use the MiSTer OSD integration, don't connect the I²C SDA and SCL signals. If you don't want to send audio back to the MiSTer for mixing, don't connect any of the I²S signals.
You can connect a real SSD1306 OLED display too, if you'd like to have both a real display and make use of the OSD integration. Just connect your display as usual to the I²C SCL and SDA signals of both the Pi and the MiSTer.

USB pin (user port)	USB signal name*	MiSTer signal name*	Wire color‡	Raspberry Pi pin	DE-10 Nano Arduino pin§
1	VBUS	+5V		2†	VCC5
2	D-	TX (MIDI out)		10	SDA
3	D+	I²C SDA		3	SCL
4	GND	GND		6	GND
5	RX-	I²S DAT	or	40	D10/SS
6	RX+	I²S BCLK	or	12	D11/MOSI
7	GND_DRAIN	I²C SCL	Bare wire	5	D12/MISO
8	TX-	I²S WS	or	35	D13/SCK
9	TX+	RX (MIDI in)	or	8¶	D8

* Signal names are as seen from the MiSTer side (i.e. USB pin 2 is MIDI out FROM the MiSTer). The "USB signal name" is simply for cross-referencing the original purpose of the USB pin; the "MiSTer signal name" is what is actually being delivered on that pin.
† Do not connect +5V if you want to use an external power supply for the Raspberry Pi.
‡ Wire colors for the RX and TX differential pairs could be swapped depending on which half of a cut USB cable you may be using.
¶ Optional, not currently used by mt32-pi.
§ This column is for connecting a DE-10 Nano directly to a Raspberry Pi. Refer to page 30 of the DE-10 Nano User Manual to locate the pin positions.