docs: add example

Author: jue89

example.js

@@ -0,0 +1,29 @@
+// We must run this as root since we are accessing hardware directly.
+// Furthermore just one instance of this driver is allowed per Pi concurrently.
+
+// Load and configure the drivers:
+const DMX = require( '.' )( {
+	// Any free GPIO can be used:
+	pinTx: 22,   // Data pin
+	pinEn: 27,   // Enable ping
+	// The signal levels can be inverted if neccessary:
+	invTx: true, // Data pin
+	invEn: true  // Enable pin
+} );
+
+function fadeDMX( ch3 ) {
+
+	// Stop when channel 3 reached 255
+	if( ch3 > 255 ) return;
+
+	// Create buffer that will be transmitted: Ch 1, 2, 4, 5 are static and Ch 3 is faded
+	let data = Buffer.from( [ 0, 128, ch3, 0, 0] );
+
+	// DMX.transmit( data ) returns a promise that is fulfilled if the data has been transmitted
+	return DMX.transmit( data ).then( () => fadeDMX( ++ch3 ) );
+
+}
+
+// Start fading and shutdown the driver when fading has been finished
+fadeDMX( 0 ).then( () => DMX.close() ).catch( console.error );
+