全部内容以 Creative Commons 署名-非商业性使用-相同方式共享 3.0 协议发布.
© Copyright 2013, 蒋鑫。 使用 Sphinx 1.2b3 创建。
当GPIO端口设置为输出并置1，会向外输出3.3V电压。注意GPIO用于输出时内部电阻很小只有31欧姆（实测34欧姆），所以在输出线路中要添加电阻，以使电流不超过16mA，否则损坏树莓派。
#!/bin/sh
test_pin_out() {
pin=$1
pin_path="/sys/class/gpio/gpio${pin}"
if [ ! -d $pin_path ]; then
echo "$pin" > /sys/class/gpio/export
fi
echo "out" > $pin_path/direction
echo "1" > $pin_path/value
sleep 2
echo "0" > $pin_path/value
}
for pin in 17 18 27 22 23 24 25; do
test_pin_out $pin
done
设置GPIO端口为OUTPUT模式，依次设置为True，输出高电平（3.3v）。Python代码：
#!/usr/bin/env python
import RPi.GPIO as GPIO
import sys, time
## Mapping between GPIO.BOARD and GPIO.BCM:
# GPIO.BOARD (Pin): 11 12 13 15 16 18 22 07
# GPIO.BCM (GPIO): 17 18 21/27 22 23 24 25 clock
# Extension Board : P0 P1 P2 P3 P4 P5 P6 P7
GPIO.setmode(GPIO.BOARD)
# Do not warning if already setup for #pin.
GPIO.setwarnings(False)
for pin in (11, 12, 13, 15, 16, 18, 22):
GPIO.setup(pin, GPIO.OUT)
print("Test pin #%s ...\t" % pin),
sys.stdout.flush()
GPIO.output(pin, True)
time.sleep(2)
GPIO.output(pin, False)
print("done")
#!/usr/bin/env ruby
require 'pi_piper'
[17, 18, 27, 22, 23, 24, 25].each do |pin|
print "Test pin ##{pin}...\t"
gpio = PiPiper::Pin.new(:pin => pin, :direction => :out)
gpio.on
sleep 2
gpio.off
puts "done"
end
当GPIO端口处于输入模式时，测量电阻处于短路状态，所以可以无需在电路中添加电阻保护，直接将3.3V电压连接到对应GPIO端口上。高电平（3V3）取值1，低电平（接地）取值0。
#!/bin/sh
test_pin_in() {
pin=$1
pin_path="/sys/class/gpio/gpio${pin}"
if [ ! -d $pin_path ]; then
echo "$pin" > /sys/class/gpio/export
fi
echo "in" > $pin_path/direction
echo "Value of GPIO #$pin is: $(cat $pin_path/value)."
}
for pin in 17 18 27 22 23 24 25; do
test_pin_in $pin
done
设置GPIO端口为OUTPUT模式，依次设置为True，输出高电平（3.3v）。Python代码：
#!/usr/bin/env python
import RPi.GPIO as GPIO
import sys, time
GPIO.setmode(GPIO.BCM)
for pin in (17, 18, 27, 22, 23, 24, 25):
GPIO.setup(pin, GPIO.IN)
print("Value of GPIO #%s is: %s." % (pin,GPIO.input(pin)))
#!/usr/bin/env ruby
require 'pi_piper'
[17, 18, 27, 22, 23, 24, 25].each do |pin|
gpio = PiPiper::Pin.new(:pin => pin, :direction => :in)
puts "Value of GPIO ##{pin} is: #{gpio.value}."
end