Merge pull request #4 from EdoB/master

Implement servoWrite and getServoPulseWidth methods + tests
deepsyx · Jun 26, 2018 · 1293c0a · 1293c0a
2 parents 9f5afe7 + 0ea3037
commit 1293c0a
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Showing 2 changed files with 20 additions and 3 deletions.
diff --git a/src/Gpio.js b/src/Gpio.js
@@ -11,6 +11,7 @@ class Gpio {
 		this.pwmValue = 0;
 		this.frequency = 31;
 		this._pwmRange = 0;
+		this.servoPulseWidth = Gpio.MED_SERVO_PULSE_WIDTH;
 
 		log(`[GPIO ${this.gpio} / constructor] Initializing...`);
 
@@ -119,13 +120,14 @@ class Gpio {
 	}
 
 	servoWrite(pulseWidth) {
-		log(`[GPIO ${this.gpio} / servoWrite] METHOD NOT IMPLEMENTED`);
+		this.servoPulseWidth = Math.min(Math.max(parseInt(pulseWidth), Gpio.MIN_SERVO_PULSE_WIDTH), Gpio.MAX_SERVO_PULSE_WIDTH);
+		log(`[GPIO ${this.gpio} / servoWrite] Setting pulseWidth = ${this.servoPulseWidth}`);
 		return this;
 	}
 
 	getServoPulseWidth() {
-		log(`[GPIO ${this.gpio} / getServoPulseWidth] METHOD NOT IMPLEMENTED`);
-		return null;
+		log(`[GPIO ${this.gpio} / getServoPulseWidth] Getting pulseWidth = ${this.servoPulseWidth}`);
+		return this.servoPulseWidth;
 	}
 }
 
@@ -156,4 +158,9 @@ Gpio.MIN_GPIO = 0; // PI_MIN_GPIO;
 Gpio.MAX_GPIO = 53; // PI_MAX_GPIO;
 Gpio.MAX_USER_GPIO = 31; // PI_MAX_USER_GPIO;
 
+/* gpio servo pulseWidth */
+Gpio.MIN_SERVO_PULSE_WIDTH = 500; // most anti-clockwise position
+Gpio.MED_SERVO_PULSE_WIDTH = 1500; // center position
+Gpio.MAX_SERVO_PULSE_WIDTH = 2500; // most clockwise position
+
 module.exports = Gpio;
diff --git a/test/gpioTest.js b/test/gpioTest.js
@@ -62,4 +62,14 @@ describe("Gpio", function() {
 		pin.pwmFrequency(1024);
 		assert(pin.getPwmFrequency(), 1024);
 	});
+
+	it("should be able to servoWrite and getServoPulseWidth", function() {
+		const pin = new Gpio(13);
+		pin.servoWrite(1200);
+		assert.equal(pin.getServoPulseWidth(), 1200);
+		pin.servoWrite(0);
+		assert.equal(pin.getServoPulseWidth(), 500);
+		pin.servoWrite(3000);
+		assert.equal(pin.getServoPulseWidth(), 2500);
+	});
 });