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Adds t2 compatibility and breaks out independent drivers
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@johnnyman727
johnnyman727 committed Nov 24, 2015
1 parent 9a581e6 commit a5d5299
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Showing 7 changed files with 735 additions and 239 deletions.
11 changes: 9 additions & 2 deletions examples/gps.js
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Expand Up @@ -11,9 +11,16 @@ var tessel = require('tessel');
var gpsLib = require('../'); // Replace '../' with 'gps-a2235h' in your own code
gpsLib.debug = 0; // switch this to 1 for debug logs, 2 for printing out raw nmea messages

// GPS uses software UART, which is only available on Port C
// GPS uses software UART, which is only available on Port C on Tessel 1
// we use Port C because it is port most isolated from RF noise
var gps = gpsLib.use(tessel.port['C']);
// Port C doesn't exist on Tessel 2 so use Port A
var portToUse = 'C';

if (!tessel.port[portToUse]) {
portToUse = 'A';
}

var gps = gpsLib.use(tessel.port[portToUse]);

// Wait until the module is connected
gps.on('ready', function () {
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245 changes: 10 additions & 235 deletions index.js
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@@ -1,243 +1,18 @@
// Copyright 2014 Technical Machine, Inc. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
var os = require('os');

var hw = process.binding('hw');
var util = require('util');
var EventEmitter = require('events').EventEmitter;

var DEBUG = 0; // Set to 1 for debug console logs, 2 for printed NMEA messages
exports.debug = DEBUG;

var GPS = function (hardware, callback) {
/*
Constructor
Args
hardware
The Tessel port to use
callback
Callback function
*/
var self = this;
self.hardware = hardware;
self.onOff = self.hardware.digital[2];
self.powerState = 'off';
self.timeoutDuration = 10*1000;
self.hasFix = false;

hw.swuart_enable();
var count = 0;

function isReady(){
// Once we are on, emit the connected event
self.emit('ready');
self._checkConnection();

if (exports.debug == 2) {
console.log("Printing out NEMA messages, this could interrupt ability for GPS lock");
setInterval(function(){
var buff = hw.swuart_receive();
console.log(buff.toString());
}, 500);
}

if (callback) {
callback();
}
function use (hardware) {
var GPS;
// If we're running Linux, this is T2
if (os.platform() === 'linux') {
// Import the T2 driver (doesn't have a binary dep)
GPS = require('./lib/tessel_2/driver');
}

// Turn the module on
function powerSequence(){
if (exports.debug) {
console.log("power sequence", count);
}
self.powerOn(function(){
// send over the gps start cmd
hw.gps_init();

setTimeout(function(){
// check for some uart data
if (hw.swuart_receive().length > 0) {
self.powerState = 'on';

isReady();
} else {
self.powerState = 'off';
// if we can't find any, error out
count++;
if (count > 3) {
self.emit("error", new Error("Could not find GPS module"));
} else {
powerSequence();
}
}
}, 1000); // hold for 1s to see if we get any nmea messages
});
// Otherwise, use the T1 driver
else {
GPS = require('./lib/tessel_1/driver');
}

// check for 1s to see gps is already on nmea setting
setTimeout(function(){
if (hw.swuart_receive().length > 0) {
// we're already in a nmea state
self.powerState = 'on';
isReady();
} else {
// we're not in a nmea state, do the power cycle
powerSequence();
}
}, 1000);

// poll every 2 seconds by default, can bump this up but it'll consume more cpu
var pollTime = 2000;
self.getPollTime = function () {
return pollTime;
};
self.setPollTime = function (time) {
time = parseInt(time, 10);
if (isNaN(time)) {
time = 2000;
if (exports.debug) {
console.log('time must be an integer between 2000 and 60000');
}
}
if (time < 2000) {
// No less than 2 seconds
if (exports.debug) {
console.log("time must be at least 2000ms (2s)");
}
time = 2000;
} else if (time > 60000) {
// No more than 60 seconds
if (exports.debug) {
console.log("time must not be greater than 60000ms (60s)");
}
time = 60000;
}
pollTime = time;
return self;
};
};

util.inherits(GPS, EventEmitter);


GPS.prototype._checkConnection = function(){
var self = this;
// poll for connections
setTimeout(function(){
if (hw.gps_get_fix()){
self.hasFix = true;
self.emit('coordinates', {
lat: hw.gps_get_latitude(),
lon: hw.gps_get_longitude(),
speed: hw.gps_get_speed(),
timestamp: hw.gps_get_time(),
datestamp: hw.gps_get_date()
});
self.emit('altitude', {
alt: hw.gps_get_altitude(),
timestamp: hw.gps_get_time(),
datestamp: hw.gps_get_date()
});
self.emit('fix', {
numSat: hw.gps_get_satellites()
});
} else {
if (self.hasFix) {
// we had a fix but we dropped it
// reduce usage on the mcu so we emit less noise
self.emit('dropped');
}
self.hasFix = false;
}

self._checkConnection();
}, self.getPollTime());
}

// Toggle the power pin of the A2235-H (attached to hardware.gpio[3]). Assumes the module knows what power state it is in.
GPS.prototype._power = function (state, callback) {
/*
Args
state
'on' - turn the power on
'off' - turn the power off
callback
Callback function
*/
// We need to switch from this state to the given state
var switchState = (state === 'on' ? 'off' : 'on');
var self = this;

// Pull power high
if (self.powerState === switchState) {
if (exports.debug) {
console.log('high');
}
self.onOff.output().high();
setTimeout(function backLow() {
if (exports.debug) {
console.log('low');
}
self.onOff.low();
// Pull power low
if (self.powerState === switchState) {
// Set a timeout for it to have time to turn on and start sending
setTimeout(callback, 500);
}
}, 250);
} else if (callback) {
callback();
}
};

// Turns the GPS chip off
GPS.prototype.powerOff = function (callback) {
/*
Try to turn the power off. Note that the A2235-H responds to a pulse, not the
state of the power pin (it toggles).
Arg
callback
Callback function; arg: err
*/
var self = this;
self._power('off', function () {
self.emit('power-off');
if (callback) {
callback();
}
});
};

// Turns the GPS chip on
GPS.prototype.powerOn = function (callback) {
/*
Try to turn the power on. Note that the A2235-H responds to a pulse, not the
state of the power pin (it toggles).
Arg
callback
Callback function; arg: err
*/
var self = this;
self._power('on', function () {
self.emit('power-on');
if (callback) {
callback();
}
});
};

function use (hardware) {
return new GPS(hardware);
}

exports.use = use;
exports.GPS = GPS;
76 changes: 76 additions & 0 deletions lib/common.js
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@@ -0,0 +1,76 @@
module.exports.loadPowerFunctions = function(GPS, DEBUG) {
// Toggle the power pin of the A2235-H (attached to hardware.gpio[3]). Assumes the module knows what power state it is in.
GPS.prototype._power = function (state, callback) {
/*
Args
state
'on' - turn the power on
'off' - turn the power off
callback
Callback function
*/
// We need to switch from this state to the given state
var switchState = (state === 'on' ? 'off' : 'on');
var self = this;

// Pull power high
if (self.powerState === switchState) {
if (DEBUG) {
console.log('high');
}
self.onOff.output().high();
setTimeout(function backLow() {
if (DEBUG) {
console.log('low');
}
self.onOff.low();
// Pull power low
if (self.powerState === switchState) {
// Set a timeout for it to have time to turn on and start sending
setTimeout(callback, 500);
}
}, 250);
} else if (callback) {
callback();
}
};

// Turns the GPS chip off
GPS.prototype.powerOff = function (callback) {
/*
Try to turn the power off. Note that the A2235-H responds to a pulse, not the
state of the power pin (it toggles).
Arg
callback
Callback function; arg: err
*/
var self = this;
self._power('off', function () {
setImmediate(function () {
self.emit('powerOff');
});
if (callback) {
callback();
}
});
};

// Turns the GPS chip on
GPS.prototype.powerOn = function (callback) {
/*
Try to turn the power on. Note that the A2235-H responds to a pulse, not the
state of the power pin (it toggles).
Arg
callback
Callback function; arg: err
*/
var self = this;
self._power('on', function () {
self.emit('power-on');
if (callback) {
callback();
}
});
};
}
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