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Added pulse-in; added debouncing

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Added the pulse-in node code. Added simple debouncing logic to
discrete-in (note: this implementation may be badly affected if there
is a lot of very fast bouncing.
This commit is contained in:
Maxwell Hadley
2014-02-23 15:20:05 +00:00
parent f46b59d69f
commit b95567dfb4
2 changed files with 272 additions and 26 deletions
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176
hardware/BBB/145-digital-in.js
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@@ -24,7 +24,7 @@ try {
require("util").log("[145-digital-in] Error: cannot find module 'bonescript'");
}
// The node constructor
// discrete-in node constructor
function DiscreteInputNode(n) {
RED.nodes.createNode(this, n);
@@ -36,38 +36,68 @@ function DiscreteInputNode(n) {
else
this.activeState = 1;
this.updateInterval = n.updateInterval * 1000; // How often to send totalActiveTime messages
this.debounce = n.debounce; // Enable switch contact debouncing algorithm
this.interruptAttached = false; // Flag: should we detach interrupt when we are closed?
this.intervalId = null; // Remember the timer ID so we can delete it when we are closed
this.currentState = 0; // The pin input state "1" or "0"
this.lastActiveTime = NaN; // The date (in ms since epoch) when the pin last went high
// switch to process.hrtime()
this.totalActiveTime = 0; // The total time in ms that the pin has been high (since reset)
this.starting = true;
this.debouncing = false; // True after a change of state while waiting for the 7ms debounce time to elapse
// Define 'node' to allow us to access 'this' from within callbacks (the 'var' is essential -
// otherwise there is only one global 'node' for all instances of DiscreteInputNode!)
var node = this;
// This function is called whenever the input pin changes state. We update the currentState
// and the ActiveTime variables, and send a message on the first output with the new state
// Note: this function gets called spuriously when the interrupt is first enabled: in this
// case x.value is undefined - we must test for this
// This function is called by the input pin change-of-state interrupt. If
// debounce is disabled, send the output message. Otherwise, if we are
// currently debouncing, ignore this interrupt. If we are not debouncing,
// schedule a re-read of the input pin in 7ms time, and set the debouncing flag
// Note: this function gets called spuriously when the interrupt is first enabled:
// in this case x.value is undefined - we must test for this
var interruptCallback = function (x) {
if (x.value != undefined && node.currentState !== Number(x.value)) {
node.currentState = Number(x.value);
var now = Date.now();
if (node.currentState === node.activeState) {
node.lastActiveTime = now;
} else if (!isNaN(node.lastActiveTime)) {
node.totalActiveTime += now - node.lastActiveTime;
if (x.value !== undefined && node.currentState !== Number(x.value)) {
if (node.debounce) {
if (node.debouncing === false) {
node.debouncing = true;
setTimeout(function () { bonescript.digitalRead(node.pin, debounceCallback); }, 7);
}
} else {
sendStateMessage(x);
}
var msg = {};
msg.topic = node.topic;
msg.payload = node.currentState;
node.send([msg, null]);
}
};
// This function is called approx 7ms after a potential change-of-state which we
// are debouncing. Terminate the debounce, and send a message if the state has
// actually changed
var debounceCallback = function (x) {
node.debouncing = false;
if (x.value !== undefined && node.currentState !== Number(x.value)) {
sendStateMessage(x);
}
};
// This function is called when either the interruptCallback or the debounceCallback
// have determined we have a 'genuine' change of state. Update the currentState and
// ActiveTime variables, and send a message on the first output with the new state
var sendStateMessage = function (x) {
node.currentState = Number(x.value);
var now = Date.now();
// switch to process.hrtime()
if (node.currentState === node.activeState) {
node.lastActiveTime = now;
} else if (!isNaN(node.lastActiveTime)) {
node.totalActiveTime += now - node.lastActiveTime;
}
var msg = {};
msg.topic = node.topic;
msg.payload = node.currentState;
node.send([msg, null]);
};
// This function is called by the timer. It updates the ActiveTime variables, and sends a
// message on the second output with the latest value of the total active time, in seconds
var timerCallback = function () {
@@ -75,21 +105,31 @@ function DiscreteInputNode(n) {
var now = Date.now();
node.totalActiveTime += now - node.lastActiveTime;
node.lastActiveTime = now;
// switch to process.hrtime()
}
var msg = {};
msg.topic = node.topic;
msg.payload = node.totalActiveTime / 1000;
node.send([null, msg]);
// Re-synchronise the pin state if we have missed a state change interrupt for some reason
bonescript.digitalRead(node.pin, interruptCallback);
// Re-synchronise the pin state if we have missed a state change interrupt for some
// reason, and we are not in the process of debouncing one
if (node.debouncing === false) {
bonescript.digitalRead(node.pin, interruptCallback);
}
};
// This function is called when we receive an input message. Clear the ActiveTime variables
// (so we start counting from zero again)
var inputCallback = function (msg) {
node.totalActiveTime = 0;
// This function is called when we receive an input message. If the topic is "load"
// set the totalActiveTime to the numeric value of the payload, if possible. Otherwise
// clear the totalActiveTime (so we start counting from zero again)
var inputCallback = function (ipMsg) {
if (String(ipMsg.topic).search("load") < 0 || isFinite(ipMsg.payload) == false) {
node.totalActiveTime = 0;
} else {
node.totalActiveTime = Number(ipMsg.payload);
}
if (node.currentState === node.activeState) {
node.lastActiveTime = Date.now();
// switch to process.hrtime()
}
if (node.starting) {
node.starting = false;
@@ -113,6 +153,7 @@ function DiscreteInputNode(n) {
node.currentState = Number(x.value);
if (node.currentState === node.activeState) {
node.lastActiveTime = Date.now();
// switch to process.hrtime()
}
// Attempt to attach a change-of-state interrupt handler to the pin. If we succeed,
// set the input event and interval handlers, then send an initial message with the
@@ -132,8 +173,89 @@ function DiscreteInputNode(n) {
}
}
// Node constructor for pulse-in
// The node constructor
function PulseInputNode(n) {
RED.nodes.createNode(this, n);
// Store local copies of the node configuration (as defined in the .html)
this.topic = n.topic; // the topic is not currently used
this.pin = n.pin; // The Beaglebone Black pin identifying string
this.updateInterval = n.updateInterval * 1000; // How often to send totalActiveTime messages
this.countType = n.countType;
this.countUnit = n.countUnit;
this.countRate = n.countRate;
this.interruptAttached = false; // Flag: should we detach interrupt when we are closed?
this.intervalId = null; // Remember the timer ID so we can delete it when we are closed
this.pulseTime = [[NaN, NaN], [NaN, NaN]];
this.pulseCount = 0;
// Define 'node' to allow us to access 'this' from within callbacks (the 'var' is essential -
// otherwise there is only one global 'node' for all instances of DiscreteInputNode!)
var node = this;
var interruptCallback = function (x) {
node.pulseTime = node.pulseTime[[1], process.hrtime()];
node.pulseCount = node.pulseCount + 1;
};
var inputCallback = function (msg) {
if (String(msg.topic).search("load") < 0 || isFinite(msg.payload) == false) {
node.pulseCount = 0;
} else {
node.pulseCount = Number(msg.payload);
}
};
var timerCallback = function () {
var now = process.hrtime();
var lastTime = pulseTime[1][0] - pulseTime[0][0] + (pulseTime[1][1] - pulseTime[0][1]) / 1e9;
var thisTime = now[0] - pulseTime[1][0] + (now[1] - pulseTime[1][1]) / 1e9;
var msg = [{ topic:node.topic }, { topic:node.topic }];
msg[0].payload = node.countUnit * node.pulseCount;
msg[1].payload = node.countRate / Math.max(thisTime, lastTime);
node.send(msg);
};
// If we have a valid pin, set it as an input and read the (digital) state
if (["P8_7", "P8_8", "P8_9", "P8_10", "P8_11", "P8_12", "P8_13", "P8_14", "P8_15",
"P8_16", "P8_17", "P8_18", "P8_19", "P8_26", "P9_11", "P9_12", "P9_13", "P9_14",
"P9_15", "P9_16", "P9_17", "P9_18", "P9_21", "P9_22", "P9_23", "P9_24", "P9_26",
"P9_27", "P9_30", "P9_41", "P9_42"].indexOf(node.pin) >= 0) {
// Don't set up interrupts & intervals until after the close event handler has been installed
process.nextTick(function () {
bonescript.pinMode(node.pin, bonescript.INPUT);
bonescript.digitalRead(node.pin, function (x) {
// Initialise the currentState based on the value read
node.currentState = Number(x.value);
// Attempt to attach a change-of-state interrupt handler to the pin. If we succeed,
// set the input event and interval handlers, then send an initial message with the
// pin state on the first output
var interruptType;
if (node.countType == "pulse") {
interruptType = bonescript.FALLING ;
} else {
interruptType = bonescript.CHANGE;
}
if (bonescript.attachInterrupt(node.pin, true, interruptType, interruptCallback)) {
node.interruptAttached = true;
node.on("input", inputCallback);
node.intervalId = setInterval(timerCallback, node.updateInterval);
} else {
node.error("Failed to attach interrupt");
}
});
});
} else {
node.error("Unconfigured input pin");
}
}
// Register the node by name. This must be called before overriding any of the Node functions.
RED.nodes.registerType("discrete-in", DiscreteInputNode);
RED.nodes.registerType("pulse-in", PulseInputNode);
// On close, detach the interrupt (if we attached one) and clear the interval (if we set one)
DiscreteInputNode.prototype.close = function () {
@@ -144,3 +266,13 @@ DiscreteInputNode.prototype.close = function () {
clearInterval(this.intervalId);
}
};
// On close, detach the interrupt (if we attached one) and clear the interval (if we set one)
PulseInputNode.prototype.close = function () {
if (this.interruptAttached) {
bonescript.detachInterrupt(this.pin);
}
if (this.intervalId !== null) {
clearInterval(this.intervalId);
}
};