Add ability to set servo position in microseconds

If servo.write value is < 544 then SERVO_WRITE degrees, otherwise SERVO_WRITE_MICROSECONDS. Includes tests.

Author: dtex

lib/particle.js

@@ -14,10 +14,10 @@ var errors = {
 };
 
 var pins = [
-  { id: "D0", modes: [0, 1, 3, 4] },
-  { id: "D1", modes: [0, 1, 3, 4] },
-  { id: "D2", modes: [0, 1, 3, 4] },
-  { id: "D3", modes: [0, 1, 3, 4] },
+  { id: "D0", modes: [0, 1, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
+  { id: "D1", modes: [0, 1, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
+  { id: "D2", modes: [0, 1, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
+  { id: "D3", modes: [0, 1, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
   { id: "D4", modes: [0, 1] },
   { id: "D5", modes: [0, 1] },
   { id: "D6", modes: [0, 1] },
@@ -26,14 +26,14 @@ var pins = [
   { id: "", modes: [] },
   { id: "", modes: [] },
 
-  { id: "A0", modes: [0, 1, 2, 3, 4] },
-  { id: "A1", modes: [0, 1, 2, 3, 4] },
+  { id: "A0", modes: [0, 1, 2, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
+  { id: "A1", modes: [0, 1, 2, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
   { id: "A2", modes: [0, 1, 2] },
   { id: "A3", modes: [0, 1, 2] },
-  { id: "A4", modes: [0, 1, 2, 3, 4] },
-  { id: "A5", modes: [0, 1, 2, 3, 4] },
-  { id: "A6", modes: [0, 1, 2, 3, 4] },
-  { id: "A7", modes: [0, 1, 2, 3, 4] }
+  { id: "A4", modes: [0, 1, 2, 3, 4], pwm: { servoMin: 1000, servoMax: 2000 }},
+  { id: "A5", modes: [0, 1, 2, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
+  { id: "A6", modes: [0, 1, 2, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
+  { id: "A7", modes: [0, 1, 2, 3, 4], pwm: { servoMin: 600, servoMax: 2400 }},
 ];
 
 var modes = Object.freeze({
@@ -252,6 +252,7 @@ function Particle(opts) {
       name: pin.id,
       supportedModes: pin.modes,
       mode: pin.modes[0],
+      pwm: pin.pwm,
       value: 0
     };
   });
@@ -479,10 +480,9 @@ Particle.prototype.pinMode = function(pin, mode) {
   return this;
 };
 
-["analogWrite", "digitalWrite", "servoWrite"].forEach(function(fn) {
+["analogWrite", "digitalWrite"].forEach(function(fn) {
   var isAnalog = fn === "analogWrite";
-  var isServo = fn === "servoWrite";
-  var action = isAnalog ? 0x02 : (isServo ? 0x41 : 0x01);
+  var action = isAnalog ? 0x02 : 0x01;
 
   Particle.prototype[fn] = function(pin, value) {
     var state = priv.get(this);
@@ -502,6 +502,67 @@ Particle.prototype.pinMode = function(pin, mode) {
   };
 });
 
+Particle.prototype.servoWrite = function(pin, value) {
+  var state = priv.get(this);
+  var buffer;
+  var offset = pin[0] === "A" ? 10 : 0;
+  var pinInt = (String(pin).replace(/A|D/i, "") | 0) + offset;
+
+  if (value < 544) {
+    buffer = new Buffer(3);
+    value = constrain(value, 0, 180);
+    buffer[0] = 0x41;
+    buffer[1] = pinInt;
+    buffer[2] = value;
+  } else {
+    buffer = new Buffer(4);
+    value = constrain(value, this.pins[pinInt].pwm.servoMin, this.pins[pinInt].pwm.servoMax);
+    buffer[0] = 0x43;
+    buffer[1] = pinInt;
+    buffer[2] = value & 0x7f;
+    buffer[3] = value >> 7;
+  }
+
+  // console.log(buffer);
+  state.socket.write(buffer);
+  this.pins[pinInt].value = value;
+
+  return this;
+};
+
+Particle.prototype.servoConfig = function(pin, min, max) {
+  var offset = pin[0] === "A" ? 10 : 0;
+  var pinInt = (String(pin).replace(/A|D/i, "") | 0) + offset;
+  var temp;
+  
+  if (typeof pin === "object" && pin !== null) {
+    temp = pin;
+    pin = temp.pin;
+    min = temp.min;
+    max = temp.max;
+  }
+
+  if (typeof pin === "undefined") {
+    throw new Error("servoConfig: pin must be specified");
+  }
+
+  if (typeof min === "undefined") {
+    throw new Error("servoConfig: min must be specified");
+  }
+
+  if (typeof max === "undefined") {
+    throw new Error("servoConfig: max must be specified");
+  }
+  
+  if (this.pins[pinInt].mode !== modes.SERVO) {
+    this.pinMode(pinInt, modes.SERVO);
+  }
+
+  pins[pinInt].pwm.servoMin = min;
+  pins[pinInt].pwm.servoMax = max;
+
+};
+
 // TODO: Define protocol for gather this information.
 ["analogRead", "digitalRead"].forEach(function(fn) {
   var isAnalog = fn === "analogRead";
@@ -812,6 +873,11 @@ Particle.prototype.close = function() {
   state.server.close();
 };
 
+function scale(value, inMin, inMax, outMin, outMax) {
+  return (value - inMin) * (outMax - outMin) /
+    (inMax - inMin) + outMin;
+}
+
 function constrain(value, lower, upper) {
   return Math.min(upper, Math.max(lower, value));
 }

package.json

@@ -1,7 +1,7 @@
 {
   "name": "particle-io",
   "description": "Particle Core & Photon IO Plugin for Johnny-Five",
-  "version": "0.14.0",
+  "version": "0.15.0",
   "homepage": "https://github.com/rwaldron/particle-io",
   "author": {
     "name": "Rick Waldron <[email protected]>",
@@ -31,6 +31,10 @@
     {
       "name": "Brian Genisio",
       "email": "<[email protected]>"
+    },
+    {
+      "name": "Donovan Buck",
+      "email": "<[email protected]>"
     }
   ],
   "keywords": [

readme.md

@@ -214,7 +214,7 @@ board.on("ready", function() {
 
 **servoWrite(pin, value)**
 
-> Sets the pin to a value between 0 and 180, where the value represents degrees of the servo horn. The value is converted to a PWM signal. PWM is available on D0, D1, A0, A1, A4, A5, A6 and A7.
+> If the value is less than 544, sets the pin to a value constrained between 0 and 180, where the value represents degrees of the servo horn. If the value is 545 or greater, sets the pin to a value in microseconds.
 
 Example:
 ```js
@@ -228,6 +228,34 @@ board.on("ready", function() {
 });
 ```
 
+```js
+var board = new Particle(...);
+
+board.on("ready", function() {
+
+  // Set the servo duty cycle to 1759 microseconds
+  // Note that the servo pwm frequency is 50mhz and 
+  // the default servo range is 600-2400 microseconds
+  this.servoWrite("D0", 1759);
+
+});
+```
+
+**servoConfig(pin, min, max)**
+
+> Sets the range for the servo PWM duty cycle. The default range is 600 - 2400 microseconds. Can be called instead of pin mode.
+
+Example:
+```js
+var board = new Particle(...);
+
+board.on("ready", function() {
+
+  this.servoConfig("D0", 690, 2310);
+
+});
+```
+
 
 **digitalRead(pin, handler)** Setup a continuous read handler for specific digital pin (D0-D7).
 

test/particle.js

@@ -759,7 +759,6 @@ exports["Particle.prototype.servoWrite"] = {
     }
     test.done();
   },
-
   servoWriteDigital: function(test) {
     test.expect(3);
 
@@ -774,7 +773,6 @@ exports["Particle.prototype.servoWrite"] = {
     }
     test.done();
   },
-
   servoWriteAnalog: function(test) {
     test.expect(3);
 
@@ -787,6 +785,61 @@ exports["Particle.prototype.servoWrite"] = {
     for (var i = 0; i < sent.length; i++) {
       test.equal(sent[i], buffer.readUInt8(i));
     }
+    test.done();
+  },
+  servoWriteOutsideRange: function(test) {
+    test.expect(3);
+
+    var sent = [0x41, 10, 180];
+
+    this.particle.servoWrite("A0", 220);
+
+    var buffer = this.socketwrite.args[0][0];
+
+    for (var i = 0; i < sent.length; i++) {
+      test.equal(sent[i], buffer.readUInt8(i));
+    }
+    test.done();
+  },
+  servoWriteMicroseconds: function(test) {
+    test.expect(4);
+
+    var sent = [0x43, 10, 14, 12];
+
+    this.particle.servoWrite("A0", 1550);
+
+    var buffer = this.socketwrite.args[0][0];
+
+    for (var i = 0; i < sent.length; i++) {
+      test.equal(sent[i], buffer.readUInt8(i));
+    }
+    test.done();
+  },
+  servoWriteMicrosecondsOutsideRange: function(test) {
+    test.expect(4);
+
+    var sent = [0x43, 10, 96, 18];
+
+    this.particle.servoWrite("A0", 3000);
+
+    var buffer = this.socketwrite.args[0][0];
+
+    for (var i = 0; i < sent.length; i++) {
+      test.equal(sent[i], buffer.readUInt8(i));
+    }
+    test.done();
+  },
+  servoConfig: function(test) {
+    test.expect(4);
+
+    test.equal(this.particle.pins[10].pwm.servoMin, 600);
+    test.equal(this.particle.pins[10].pwm.servoMax, 2400);
+    
+    this.particle.servoConfig("A0", 1000, 2000);
+    
+    test.equal(this.particle.pins[10].pwm.servoMin, 1000);
+    test.equal(this.particle.pins[10].pwm.servoMax, 2000);
+    
     test.done();
   }
 };