Book Image

Learning Beaglebone Python Programming

Book Image

Learning Beaglebone Python Programming

Overview of this book

Table of Contents (19 chapters)

Blink


Now that we have our transistor driving the LED at its full current from GPIO0_30 (P9.11), let's use Adafruit_BBIO to write a program that blinks it at a fixed interval. The first step is to load the universal-io Device Tree overlay as described previously:

# echo cape-universaln > /sys/devices/bone_capemgr.*/slots

Next you'll need to use the config-pin command to manually configure the pin as a digital output:

# config-pin P9_11 in

Now that the pin is configured properly, open a new file in Cloud9 called blink.py with the following code:

from Adafruit_BBIO import GPIO
import time

LED_PIN = "GPIO0_30"
GPIO.setup(LED_PIN, GPIO.OUT)

while True:
  GPIO.output(LED_PIN, GPIO.HIGH)
  time.sleep(0.5)
  GPIO.output(LED_PIN, GPIO.LOW)
  time.sleep(0.5)

Press Run and you should see the LED turn on for half a second, turn off for half a second, and repeat forever. Alright! When you're done watching the light show you can press the Stop button or hit Ctrl + C in the terminal that opened when...