Beaglebone black Adafruit on Debian

Question

I'm using Beaglebone black Rev c. It comes with Debian and Adafruit library for GPIO. I tried a simple program to blink the 4 built in LEDs. The program doesn't blink the LEDs. I tried it with bonescript and it works. I'm logged in as the root user. Can you help me understand why the Adafruit library doesn't work.

The bonescript code is the default code provided - this works:

var b = require('bonescript');
b.pinMode('USR0', b.OUTPUT);
b.pinMode('USR1', b.OUTPUT);
b.pinMode('USR2', b.OUTPUT);
b.pinMode('USR3', b.OUTPUT);
b.digitalWrite('USR0', b.HIGH);
b.digitalWrite('USR1', b.HIGH);
b.digitalWrite('USR2', b.HIGH);
b.digitalWrite('USR3', b.HIGH);
setTimeout(restore, 2000);

Here's my Python code snippet. I'm logged in as root and the Program runs but I don't see a change in the LEDs:

import Adafruit_BBIO.GPIO as GPIO
import time

print "Start of program"

GPIO.setup ('USR0', GPIO.OUT)
GPIO.setup ('USR1', GPIO.OUT)
GPIO.setup ('USR2', GPIO.OUT)
GPIO.setup ('USR3', GPIO.OUT)


while (True):
    GPIO.output ('USR0', GPIO.HIGH)
    GPIO.output ('USR1', GPIO.HIGH)
    GPIO.output ('USR2', GPIO.HIGH)
    GPIO.output ('USR3', GPIO.HIGH)
    time.sleep (1)

    GPIO.output ('USR0', GPIO.LOW)
    GPIO.output ('USR1', GPIO.LOW)
    GPIO.output ('USR2', GPIO.LOW)
    GPIO.output ('USR3', GPIO.LOW)

    time.sleep (1)

Thomas Hsieh Thomas Hsieh · Accepted Answer · 2015-04-05T03:35:15

I have not tried the Adafruit library, but I think the GPIO module is intended for the GPIO pins – pins that supports GPIO mode for external circuitry. The four built-in LEDs are not GPIO pins.

Beaglebone black Adafruit on Debian

2 Answers