UTC UT84520

CMOS IC

QW-R502-004,A

Function Descriptions

Legacy PS/2 mouse operating

A) Operating mode

There are four operating modes in PS/2 mouse:

a. Reset mode:

In this mode a self-test in initiated during power-on or by a Reset command. After reset signal,

PS/2 mouse will

(a) Send completion code AA & ID code 00.

(b) Set default:

Sampling rate: 100 reports/s

Non-autospeed

Stream mode

2 dots/count

Disable

b. Stream Mode:

The maximum rate of transfer is the programmed sampling rate.

Data report is transmitted if

(a) switch is pressed

(b) movement has been detected

c. Remote Mode:

Data is transmitted only in response to a Read Data command

d. Wrap Mode:

Any byte of data sent by the system. Except hex EC (Reset Wrap mode) or hex FF (Reset).

Is returned by UT84520.

B).PS/2 Mouse Data Report

a). In stream mode: A data report is sent at the end of a sampling interval.

b). In remote mode: A data report is sent in response to Read Data command

c). Data report format:

Byte

Bit

Description

1

0

Left button status; l=pressed

1

Right button status; 1=pressed

2

Middle button status; 1=pressed

3

Reserve

4

X data sign; 1=negative

5

Y data sign; 1=negative

6

X data overflow; 1=overflow

7

Y data overflow; 1=overflow

2

0-7 X data (D0-D7)

3

0-7 Y data (D0-D7)