#!/usr/bin/env python
# //////////////////////////////////////
# 	internalLED.py
# 	Blinks A USR LED.
# 	Wiring:
# 	Setup:
# 	See:
# //////////////////////////////////////
import time

ms = 250      # Blink time in ms
LED = 'usr0'; # LED to blink
LEDPATH = '/sys/class/leds/beaglebone:green:'+LED+'/brightness'

state = '1'    # Initial state

f = open(LEDPATH, "w")

while True:
    f.seek(0)
    f.write(state)
    if (state == '1'):
        state = '0'
    else:
        state = '1'
    time.sleep(ms/1000)

#!/usr/bin/env node
// //////////////////////////////////////
// 	internalLED.js
// 	Blinks the USR LEDs.
// 	Wiring:
// 	Setup:
// 	See:
// //////////////////////////////////////
const fs = require('fs');
const ms = 250;     // Blink time in ms
const LED = 'usr0'; // LED to blink
const LEDPATH = '/sys/class/leds/beaglebone:green:'+LED+'/brightness';

var state = '1';    // Initial state

setInterval(flash, ms);    // Change state every ms

function flash() {
    fs.writeFileSync(LEDPATH, state)
    if(state === '1') {
        state = '0';
    } else {
        state = '1';
    }
}

#!/usr/bin/env python
# ////////////////////////////////////////
# //	externalLED.py
# //	Blinks an external LED wired to P9_14.
# //	Wiring: P9_14 connects to the plus lead of an LED.  The negative lead of the
#			LED goes to a 220 Ohm resistor.  The other lead of the resistor goes
#			to ground.
# //	Setup:
# //	See:
# ////////////////////////////////////////
import time
import os

ms = 250        # Time to blink in ms
# Look up P9.14 using gpioinfo | grep -e chip -e P9.14.  chip 1, line 18 maps to 50
pin = '50'

GPIOPATH='/sys/class/gpio/'
# Make sure pin is exported
if (not os.path.exists(GPIOPATH+"gpio"+pin)):
    f = open(GPIOPATH+"export", "w")
    f.write(pin)
    f.close()

# Make it an output pin
f = open(GPIOPATH+"gpio"+pin+"/direction", "w")
f.write("out")
f.close()
 
f = open(GPIOPATH+"gpio"+pin+"/value", "w")
# Blink
while True:
    f.seek(0)
    f.write("1")
    time.sleep(ms/1000)

    f.seek(0)
    f.write("0")
    time.sleep(ms/1000)
f.close()

#!/usr/bin/env node
////////////////////////////////////////
//	externalLED.js
//	Blinks the P9_14 pin
//	Wiring:
//	Setup:
//	See:
////////////////////////////////////////
const fs = require("fs");

// Look up P9.14 using gpioinfo | grep -e chip -e P9.14.  chip 1, line 18 maps to 50
pin="50";

GPIOPATH="/sys/class/gpio/";
// Make sure pin is exported
if(!fs.existsSync(GPIOPATH+"gpio"+pin)) {
    fs.writeFileSync(GPIOPATH+"export", pin);
}
// Make it an output pin
fs.writeFileSync(GPIOPATH+"gpio"+pin+"/direction", "out");

// Blink every 500ms
setInterval(toggle, 500);

state="1";
function toggle() {
    fs.writeFileSync(GPIOPATH+"gpio"+pin+"/value", state);
    if(state == "0") {
        state = "1";
    } else {
        state = "0";
    }
}

#!/usr/bin/env python3
# //////////////////////////////////////
# 	toggle1.py
#  Toggles the P9_14 pin as fast as it can. P9_14 is line 18 on chip 1.
# 	Wiring:	Attach an oscilloscope to P9_14 to see the squarewave or 
#          uncomment the sleep and attach an LED.
# 	Setup:	sudo apt update; pip install gpiod
# 	See:	https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/bindings/python/examples
# //////////////////////////////////////

import gpiod
import time

LED_CHIP = 'gpiochip1'
LED_LINE_OFFSET = [18]  # P9_14

chip = gpiod.Chip(LED_CHIP)

lines = chip.get_lines(LED_LINE_OFFSET)
lines.request(consumer='blink', type=gpiod.LINE_REQ_DIR_OUT)

while True:
    lines.set_values([0])
    time.sleep(0.1)
    lines.set_values([1])
    time.sleep(0.1)