EM84502

PS/2 MOUSE CONTROLLER

2

* This specification are subject to be changed without notice.

6.18.1998

V

DD

Power

OP

I

X, Y inputs.

Floating : Comparator input.

GND : Schmitt trigger input.

Short to OSC OUT : Testing Mode.

OSCOUT

O

Clock output.

CLK

I/O

8042 auxiliary port CLK line.

DATA

I/O

8042 auxiliary port DATA line.

V

SS

Ground

R

I

Three key-switches exert seven different combinations totally. Both key-pressed

M

and key-released signals will be sent accomplanied with horizontal and vertical

L

state. The status of the key-switches will be preserved, whenever the value of

horizontal or vertical counters will present at DATA. And the debounce interval

for both key-press and key-release is 12 ms.

X1

I

Four photo-couple signals denote UP, DOWN, LEFT, and RIGHT state.

X2

During the scaning period, as long as the photo-couples change their states, the

Y1

value of vertical or horizontal counter will increase or decrease accordingly.

Y2

OSCR

I

30 Kohm

±5% pull low for 35 KHz oscillation.

FUNCTION DESCRIPTIONS

A) Operating mode

There are four operating modes in PS/2 mouse:

i). Reset Mode:

In this mode a self-test is initiated during power-on or by a Reset command. After reset signal, PS/2

mouse will send:

1). Completion code AA & ID code 00.

FUNCTIONAL BLOCK DIAGRAM

D

E

T

E

C

T

O

R

M

O

T

I

O

N

I

M

M

U

N

IT

Y

N

O

I

S

E

D

E

B

O

U

N

C

E

C

O

N

V

E

R

T

E

R

D

A

T

A

D

E

C

O

D

E

R

C

O

M

M

A

N

D

COUNTER

TIMING

CONTROLLER

DATA

I/O

SYSTEM

CLOCK

GENERATOR

OP

X1

X2

Y1

Y2

L

M

R

OSCR

OSC OUT

DATA

CLK

Symbol

I/O

Function

PIN DESCRIPTIONS