array-gpio/test/pwm.test.js

array-gpio is low-level javascript library for Raspberry Pi using direct register access.

const assert = require('assert');
const sinon = require('sinon');

const r = require('array-gpio');
r.debug(1);

describe('\nCreating a pwm object ...', function () {
  describe('Create a pwm object using .setPWM(pin) along w/ i2c, spi and gpio objects', function () {
    it('should return a pwm object', function (done) {
       
    try{

			var pwm = r.setPWM(33);
		  assert.strictEqual( typeof pwm, 'object');

			var spi = r.SPI();
		  assert.strictEqual( typeof spi, 'object');

			var i2c = r.I2C();
		  assert.strictEqual( typeof i2c, 'object');

			// create an input object
			var sw = r.in(15, 19);
			assert.strictEqual( typeof sw, 'object');

			// create an output object
      var led = r.out(36, 37);
      assert.strictEqual( typeof led, 'object');

		  // test only
		  pwm.enable();
		  pwm.start();

			// set clock frequency using a div value of 1920
			pwm.setClockFreq(1920); // sets clock freq to 10kHz or 0.1 ms time resolution for T and pw 
			 
			// set period (T) of the pulse
			pwm.setRange(1000); // 1000 x 0.1 ms = 100 ms (actual period T)

      pwm.pulse();
		  pwm.setData(100);
		  pwm.stop();
		
    }
		catch(e){
      done();
    }
    
    sw.close();
    spi.end();
    i2c.end(); 
    pwm.close();
    done();

    });
  });
  describe('Create a pwm object using .PWM(pin, freq, T, pw) method', function () {
    it('should return a pwm object', function (done) {
       
    try{

			var spi = r.SPI();
		  assert.strictEqual( typeof spi, 'object');
			var i2c = r.I2C();
		  assert.strictEqual( typeof i2c, 'object');

		  // test another pwm pin
		  var pin  = 35;    /* channel 2, alt-function 0 */
			var freq = 10;    /* 10 kHz provides 0.1 ms time resolution */
			var T    = 200;   /* 200 x 0.1 ms = 20 ms */
			var pw   = 10;    /* 10  x 0.1 ms = 1.0 ms, home position */
			 
			// start PWM and initialize with above details
			var pwm1 = r.PWM(pin, freq, T, pw);
		  assert.strictEqual( typeof pwm1, 'object');

		  var sw = r.setInput(19);
			assert.strictEqual( typeof sw, 'object');

		  // test only
		  pwm1.enable();
		  pwm1.start();

		  pwm1.pulse(10);
		  pwm1.stopPulse();
		
    }
		catch(e){
      done();
    }

    sw.close();
    spi.end();
    i2c.end(); 
    pwm1.close();
    done();

    });
  });
});