Electrical

An ESPxx is using up to ~200mA of current, the SSD1322 up to ~150mA. This all depends on the quality of used boards, workload, shown pixels and so on. Please keep this in mind when connecting all this stuff to MiSTer's USB port, especially when using passive USB hubs in connection with other devices, like keyboards, mices, joysticks ... A single originating USB port delivers a current of 500mA maximum.

Connection between ESP and OLED

OLED SSD1322	ESP32 TTGO-T8	Function
1	GND	GND/VSS
2	3.3V	Power/VDD
3		NC
4	18	SPI SCLK
5	23	SPI MOSI
6		NC
7		GND
8		GND
9		GND
10		GND
11		GND
12		GND
13		GND
14	25	OLED DC
15	27	OLED RST
16	26	OLED CS

See also https://forum.arduino.cc/index.php?topic=500292.msg3414630#msg3414630