The examples in this section show LXTerminal on a Pi running Raspbian.
For a mapping diagram and overlay for your Pi, see Pin-to-Module Mapping.
Read all GPIO pins
A value of 0 means the I/O point is On; 1 means it’s Off.
Syntax
gpio readall
In this image, highlighted GPIO pins are mapped to I/O points.
Don’t let the column names in this chart confuse you. In a Readall chart from LXTerminal, the GPIO pin numbers are in the column labeled “BCM.”
Read a GPIO pin
This example:
- Configures GPIO pin 21 as input.
- Reads the input point mapped to GPIO 21 and writes its value to the terminal.
The input point is at rack position 0, and its status is 0 (On).
Syntax
gpio -g mode [GPIO pin number] in
gpio -g read [GPIO pin number]
Write to output
This example:
- Configures GPIO pin 20 as output.
- Turns On the output point mapped to the GPIO.
- Reads and writes the point’s value to the terminal.
- Turns Off the point.
- Reads and writes the point’s value.
Syntax
gpio -g mode [GPIO pin number] out
gpio -g write [GPIO pin number] 0
gpio -g read [GPIO pin number]
gpio -g write [GPIO pin number] 1
gpio -g read [GPIO pin number]