UDC

There is a USB client on handheld Vita devices. It uses a proprietary multi-connector on the OLED (PCH-1XXX) units and a micro-USB on the LCD (PCH-2XXX) units.

PCH-1XXX Pinout

Because of the existence of the USB ethernet adaptor, that means there exists a way to use the port in host mode probably through USB OTG or something similar.

Pin	Name	Description
1	Power?	No known use (N/C on cables, USB ethernet), goes to SN99057 pins 31-32
2	Power?	Same net as pin 1
3	Host detect?	GND on Vita and charger cable, connected to something on USB ethernet adapter
4	Digital audio out	To audio codec IC
5	Digital audio out	Same net as pin 4
6	UART RX	See UART Console
7	UART TX	See UART Console
8	UART CTS	See UART Console
9	UART RTS	See UART Console
10	Audio?	To audio codec IC
11	?Headset GND?	To Syscon
12	?Headset?	To Syscon
13	?	To Syscon
14	?GND?	GND on Vita and USB ethernet adapter, N/C on charging cable
15	?Peripheral Detect?	To large ceramic chip, 125K pull-down
16	GND	GND on Vita, N/C on USB ethernet and charging cable
17	VCC	+5V VDC
18	VCC	Same net as pin 17
19	GND	GND on Vita and charging cable, N/C on USB ethernet
20	D-	USB Data
21	D+	USB Data

PCH-2XXX Pinout

Port is a standard micro-USB Type B. Highly likely that USB OTG is supported in hardware although there's no evidence that it's enabled in software.

Pin	Name	Description
1	VCC	+5V VDC
2	D+	USB Data
3	D-	USB Data
4	ID	USB OTG
5	GND	Ground