diff --git a/lib/intval/index.js b/lib/intval/index.js
index fc2d553..3cb32c9 100644
--- a/lib/intval/index.js
+++ b/lib/intval/index.js
@@ -5,6 +5,7 @@ const gpio = require('gpio')
 class Intval {
 	constructor () {
 		this._pin = {}
+		this._startFrame = 0
 		this._declarePins()
 	}
 	_declarePins () {