DESCRIPTION
The UT84520 Scrolling Mouse Controller is specially designed to control PS/2 mouse device． This single chip can interface with three key-switches and 4X-Y photo-couples plus Z-axis directly to 8042 controller．
There are four types of Z-axis inputs used to implement scrolling mouse functionality．

FEATURES
* Using 50KΩ +5% resistor for RC oscillation．
* Compatible with legacy PS/2 mouse．
* Compatible with Microsoft PS/2 scrolling mouse．
* Built-in noise immunity circuit．
* The sampling rate of motion detector is up to 65KHz．
* Built-in three step dynamic input impedance．
* Three key-switches and four photo-couples inputs．
* Photo couple test mode included﹒
* Low power dissipation．
* Two types Z direction input:
   1.Photo couples input
   2.Mechanical input