Now you can turn your phone or android device into Digital Clock!

If you want screen to stays awake always you can install:
"Stay Awake - Keep Screen On" app by itsasoftware.
It will keep screen always on.

OR

Go to "Settings", then tap "About device" or "About phone".
Scroll down, then tap "Build number" seven times.
The "Developer options" menu will now appear in your Settings menu.
Then enable option "Stay Awake". This will only stay awake your phone when its charging.