uci-interrupt/src/interrupt.js

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JavaScript
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2017-05-26 08:15:54 -07:00
'use strict'
// Creates an ES6 Interrupt class wrapper using the pigio C library and pigpio javascript wrapper package
// The pigipio C library is specifically coded for the Raspberry Pi but might be adapatable to any single board computer (sbc) with Gpios
// assuming they would be pigio C, compatiable.
// Must have pigpio C library installed first.
// On interrupt emits "fired" which can be caught by the code calling this interrupt instance for handling
// Understand there are two interrupts here. One is this class and one on the sbc/rpi via pigpio
// The sbc/pigpio interrupt emits an event which is listened for by this class which then emits
// a "fired" event which can be can be listed to by having a handle to an instance this class.
const
pigpio = require('pigpio'),
sbcGpio = pigpio.Gpio,
EventEmitter = require('events')
class Interrupt extends EventEmitter {
constructor(pin_number, handler, opts = {}) {
super()
this.pin_number = pin_number
this.handler = handler
this.mode = sbcGpio.INPUT
this.pull = opts.pull ? opts.pull : sbcGpio.PUD_DOWN
this.edge = opts.edge ? opts.edge : sbcGpio.RISING_EDGE
this.sbc_interrupt = new sbcGpio(
this.pin_number, {
mode: this.mode,
pullUpDown: this.pull,
// do not! set edge here as it will start the emitter -- see pigio js
}
)
}
// init() {
//
// // console.log(`initialize interrupt ${this.pin_number}`)
// return Promise.resolve()
//
// }
get pin() {
return this.pin_number
}
async start() {
console.log(`starting interrupt on pin ${ this.pin_number}`)
// for cntrl-c exit of interrupt
process.on('SIGINT', () => {
this.exit().then((resp) => console.log('\n', resp)) // unexport on cntrl-c
.catch(err => console.log('error:', err))
})
let interrupt = this // scope `this` for use in the listener for each interrupt
// console.log(`interrupt listener set for rpi ${interrupt.pin_number}`)
this.sbc_interrupt.on('interrupt', function () {
// console.log(`the sbc interrupt tripped by sbc pin ${interrupt.pin_number}`)
interrupt.emit('fired') // emit an event that can be listened for by the device that created the interrupt instance
})
// rock n roll!!, start the pigpio interrupt
this.sbc_interrupt.enableInterrupt(this.edge)
}
// manual firing for testing
fire() {
let interrupt = this
console.log('manually firing interrupt', this.handler)
this.emit('fired')
}
exit() {
pigpio.terminate()
return Promise.reject(`keyboard termination...terminating interrupt on pin ${this.pin_number}`)
}
}
module.exports = Interrupt