PS/2 SCROLLING MOUSE CONTROL CIRCUIT

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