Program to blink external LEDs

Let's write LED blinking code in Python. Connect one external LED in series with a resistor to pin P8_10 like we did in Chapter 3, Blinking External LEDs. Type the following program in Cloud9, save it as blink_external_LED.py and run. You should be able to see an LED blinking each second:

The code for blink_external_LED.py is as follows:

#!/usr/bin/python
from time import sleep       ##Needed to call sleep()
import Adafruit_BBIO.GPIO as GPIO

led = "P8_10"

GPIO.setup(led,GPIO.OUT)

while True:
    GPIO.output(led,GPIO.HIGH)
    sleep(1)
    GPIO.output(led,GPIO.LOW)
    sleep(1)

Explanation

Now, let's go through the above-mentioned code snippet one step at a time. If you observed, there is no semicolon (;) at the end of lines in Python. There are no curly braces to indicate statements inside a while loop. Statements inside a loop are indented. Here is a line-by-line explanation of the code.

1. We declared that the interpreter of this program in /usr/bin/python. Now...