upm/examples/javascript/groveledbar.js
Mihai Tudor Panu 89d5de43e0 license: update to SPDX style license text throughout
Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
2020-03-05 15:13:36 -08:00

59 lines
1.7 KiB
JavaScript

/*
* Author: Zion Orent <zorent@ics.com>
* Copyright (c) 2015 Intel Corporation.
*
* This program and the accompanying materials are made available under the
* terms of the The MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
*/
var LEDBar = require("jsupm_my9221");
// Instantiate a MY9221, we use D8 for the data, and D9 for the
// data clock. This was tested with a Grove LED bar.
var myLEDBar = new LEDBar.GroveLEDBar(8, 9);
var directionBool = true;
// A note on timing:
// In the C++ example, the system sleeps 10 times for 50 milliseconds
// between each LED lighting. After the LED has reached the last light
// of the cycle, the system sleeps again for 1 second.
// The sleeps are cumulative, so the system has slept for 1.5 seconds
// sum total for each cycle.
// setInterval and setTimeout make asynchronous function calls;
// they aren't cumulative.
// In order to approximate the behavior of the C++ example, we need
// to call each iteration 1.5 seconds apart instead of 1 second apart.
var myInterval = setInterval(function()
{
// start showing LED strip with just the first one lit
show_LED(1, directionBool);
}, (1000 + (10*50)) );
function show_LED(level, direction)
{
// If it's less than 10
// light up the LED now
// call show_LED again in 50 ms
if (level <= 10)
{
myLEDBar.setBarLevel(level, directionBool);
setTimeout(show_LED, 50, ++level, directionBool);
}
// Switch LED lighting directions between lighting cycles
else
directionBool = !directionBool;
}
// When exiting: clear LED strip lights, clear interval, print exit message
process.on('SIGINT', function()
{
myLEDBar.setBarLevel(0, true);
clearInterval(myInterval);
console.log("Exiting...");
process.exit(0);
});