0 — PL_IO_NUM_0:

Socket 1, control line C.

1 — PL_IO_NUM_1:

Socket 3, control line C.

2 — PL_IO_NUM_2:

Socket 5, control line C.

3 — PL_IO_NUM_3:

Socket 7, control line C.

4 — PL_IO_NUM_4:

Socket 9, control line C.

5 — PL_IO_NUM_5:

Socket 11, control line C.

6 — PL_IO_NUM_6:

Not connected.

7 — PL_IO_NUM_7:

Not connected.

8 — PL_IO_NUM_8_RX0⁽¹⁾:

Socket 1, control line B. This line is also the RX/W1in/din input of serial port 0.

9 — PL_IO_NUM_9_TX0⁽²⁾:

Socket 1, control line A. This line is also the TX/W1out/dout output of serial port 0.

10 — PL_IO_NUM_10_RX1⁽¹⁾:

Socket 3, control line B. This line is also the RX/W0&1in/din input of serial port 1.

11 — PL_IO_NUM_11_TX1⁽²⁾:

Socket 3, control line A. This line is also the TX/W1out/dout output of serial port 1.

12 — PL_IO_NUM_12_RX2⁽¹⁾:

Socket 5, control line B. This line is also the RX/W0&1in/din input of serial port 2.

13 — PL_IO_NUM_13_TX2⁽²⁾:

Socket 5, control line A. This line is also the TX/W1out/dout output of serial port 2.

14 — PL_IO_NUM_14_RX3⁽¹⁾:

Socket 7, control line B. This line is also the RX/W0&1in/din input of serial port 3.

15 — PL_IO_NUM_15_TX3⁽²⁾:

Socket 7, control line A. This line is also the TX/W1out/dout output of serial port 3.

16 — PL_IO_NUM_16_INT0:

Socket 1, control line D. This is also interrupt line 0.

17 — PL_IO_NUM_17_INT1:

Socket 3, control line D. This is also interrupt line 1.

18 — PL_IO_NUM_18_INT2:

Socket 5, control line D. This is also interrupt line 2.

19 — PL_IO_NUM_19_INT3:

Socket 7, control line D. This is also interrupt line 3.

20 — PL_IO_NUM_20_INT4:

Socket 9, control line D. This is also interrupt line 4.

21 — PL_IO_NUM_21_INT5:

Socket 11, control line D. This is also interrupt line 5.

22 — PL_IO_NUM_22_INT6:

Not connected.

23 — PL_IO_NUM_23_INT7:

Not connected.

24 — PL_IO_NUM_24:

LCD connector, data bus, line 0 (P0.0).

25 — PL_IO_NUM_25:

LCD connector, data bus, line 1 (P0.1).

26 — PL_IO_NUM_26:

LCD connector, data bus, line 2 (P0.2).

27 — PL_IO_NUM_27:

LCD connector, data bus, line 3 (P0.3).

28 — PL_IO_NUM_28:

LCD connector, data bus, line 4 (P0.4).

29 — PL_IO_NUM_29:

LCD connector, data bus, line 5 (P0.5).

30 — PL_IO_NUM_30:

LCD connector, data bus, line 6 (P0.6).

31 — PL_IO_NUM_31:

LCD connector, data bus, line 7 (P0.7).

32 — PL_IO_NUM_32:

Socket 9, control line A.

33 — PL_IO_NUM_33:

Socket 9, control line B.

34 — PL_IO_NUM_34:

Socket 11, control line A.

35 — PL_IO_NUM_35:

Socket 11, control line B.

36 — PL_IO_NUM_36:

Keypad connector, return line 1 (for the left-most button, active LOW).

37 — PL_IO_NUM_37:

Keypad connector, return line 2 (active LOW).  

38 — PL_IO_NUM_38:

Keypad connector, return line 3 (active LOW).  

39 — PL_IO_NUM_39:

Keypad connector, return line 4 (for the right-most button, active LOW).  

40 — PL_IO_NUM_40:

LCD connector, CS line (active LOW).

41 — PL_IO_NUM_41:

LCD connector, RD line (active LOW).

42 — PL_IO_NUM_42:

LCD connector, WR line (active LOW).

43 — PL_IO_NUM_43:

LCD connector, DC line.

44 — PL_IO_NUM_44:

Keypad connector, reset line (for the sensor IC of the keypad, active LOW).

45 — PL_IO_NUM_45_CO⁽³⁾:

A square wave output controlled by the beep. object. This output is driving a buzzer.

46 — PL_IO_NUM_46:

Signal strength LED bar control circuit, reset line.

47 — PL_IO_NUM_47:

Signal strength LED bar control circuit, clock line.

48 — PL_IO_NUM_48:

Signal strength LED bar control circuit, data line.

49 — PL_IO_NUM_49:

Wireless add-on socket, CS line.

50 — PL_IO_NUM_50:

Wireless add-on socket, DO line.

51 — PL_IO_NUM_51:

Wireless add-on socket, RST line.

52 — PL_IO_NUM_52:

Wireless add-on socket, DI line.

53 — PL_IO_NUM_53:

Wireless add-on socket, CLK line.

54 — PL_IO_NUM_54:

LCD connector, backlight control line (active LOW).

55 — PL_IO_NUM_55:

LCD connector, RST line (active low).

56 — PL_IO_NULL:

This is a NULL line that does not physically exist. The state of this line is always detected as LOW. Setting this line has no effect.