SanDisk Sansa e2x0 (v1) Port Pin Assignments

GPIO

	GPIOA		GPIOG
Port pin	I/O/F	Description	I/O/F	Description
0	-		-
1	O	Unknown, default 0	-
2	O	Unknown, default 0	-
3	O	Unknown, default 0	-
4	O	Unknown, default 0	-
5	O	Unknown, default 0	O	ATA Controller
6	O	Unknown, default 0	O	ATA Controller
7	I	ATA Controller (0 = MicroSD card inserted)	O	Scrollwheel light (1=on,0=off)

	GPIOB		GPIOH
Port pin	I/O/F	Description	I/O/F	Description
0	-		-
1	-		-
2	-		-
3	-		O	FM NR_W (1=tuner write mode, 2=tuner read mode)
4	I	USB Controller IRQ (Req. on level change)	O	FM CLOCK (tuner interface clock)
5	O	LCD Clock	I/O	FM DATA (BIDI Pin: I when reading tuner, O when writing to tuner)
6	I	LCD Data In	I	Scroll wheel data
7	O	LCD Data Out	I	Scroll wheel data

	GPIOC		GPIOI
Port pin	I/O/F	Description	I/O/F	Description
0	-		-
1	-		-
2	-		-
3	I/O*	O-Set to 1 by BL, I-AS3514 IRQ	-
4	-		-
5	-		-
6	-		-
7	-		-

	GPIOD		GPIOJ
Port pin	I/O/F	Description	I/O/F	Description
0	O	ATA Controller	-
1	O	ATA Controller	-
2	O	ATA Controller	-
3	O	ATA Controller	-
4	O	ATA Controller	-
5	-		-
6	O	LCD CS	-
7	-		-

	GPIOE		GPIOK
Port pin	I/O/F	Description	I/O/F	Description
0	-		-
1	-		-
2	-		-
3	-		-
4	-		-
5	-		-
6	-		-
7	-		-

	GPIOF		GPIOL
Port pin	I/O/F	Description	I/O/F	Description
0	I	Rec	-
1	I	Down	-
2	I	Right	-
3	I	Left	-
4	I	Select	-
5	I	Up	-
6	I	Power/Menu	-
7	I	Hold	-

Data Cable

Port pin	Description
1	Power (+5V)
2	Power (+5V)
3	Ground
4	USB Data +
5	USB Data -
6	Ground
7	Video +
8	Audio Right (Line out)
9	Audio Left (Line out)
10
11
12
13	Ground
14	Video +
15
16
17
18	Ground
19
20	Ground
21
22
23
24	something (visible trace)
25	something (visible trace)
26	something (visible trace)
27	Audio Right + (Line out)
28	Audio Left + (Line out)
29	Audio Out Common
30	Dedicated audio ground

Note: Unconfirmed info taken from here and here.