EM83702

ALL IN ONE MOUSE CONTROLLER

* This specification are subject to be changed without notice.

4.15.1996

EM83702

ALL IN ONE MOUSE CONTROLLER

GENERAL DESCRIPTION

The EM83702 Mouse Controller is specially designed to control mouse device. This single chip can interface
three key-switches and four photo-couple direct to RS-232C. The EM83702 does not need any external power
supply,so the mouse can go without a power line. It is versatile with both microsoft and mouse system.
Debouncing circuit were provided to prevent false entry and to improve the accuracy. In 1200 baud rate non-auto
speed with 200 DPI wheels and photo-couples, the scanning is 650 mm/sec without missing a dot in microsoft
mode,and the scanning speed can up to 770 mm/sec in mouse system mode.

FEATURES

· Built-in two zener diode between V

and V

, RTS and V

· Buit-in noise immunity circuit.
· CMOS DIP 16 pins package & SOP 16 pins package.
· Low power dissipation.
· Use 32.768 kHz crystal or 3.58MHz resonator.
· Oscillator circuits on-chip.
· Serial output in 1200 baud rate.
· Can be powered directly from RS-232C.
· Can drive directly to RS-232C.
· Three key-switches and four photo-couples inputs.
· Both key-in and key-release debounce interval 13 ms.
· Through three key-switches input, EM83702 can exert seven different output.
· The sampling rate of motion detector is 65 KHz.

APPLICATIONS

· Optical mouse or pen-mouse
· Mechanical mouse or pen-mouse
· Optomechanical mouse or pen-mouse
· Mechanical track ball
· Optomechanical track ball

Patent Number : 38715, 95661 (R.O.C)
Patent Pending : 84200836 (R.O.C)

EM83702

ALL IN ONE MOUSE CONTROLLER

* This specification are subject to be changed without notice.

4.15.1996

PIN ASSIGNMENTS

OSC.IN

OSC.OUT

RTS

RXD

VSS

OPT

EM83702A

OPT

OSC.IN

OSC.OUT

RTS

RXD

VSS

EM83702B

FUNCTIONAL BLOCK DIAGRAM

SYSTEM CLOCK

GENERATOR

LEVEL-SHIFT

CIRCUIT

MODE

SELECTOR

TIMING

CONTROLLER

P/S

MULTIPLEXER

COUNTER

RXD

OPT

OSC.OUT

OSC.IN

RTS

PIN DESCRIPTIONS

Symbol

I/O

Function

Crystal type select : "0" or floating, select 32.768KHz crystal. "1" select 3.58MHz
resonator.

When this pin is connected to V

, then EM83702 is assigned to operate

under the microsoft mode only. If the pin is connected to V

, then EM83702

will operate under the mouse system mode.
However if this pin is "floating", then EM83702 is on the "power on initiation"
situation and if any one of three buttons is chosen, thence EM83702 will operate
under the mouse mode. And while the whole system is on "power on initiation".No
key is chosen then operation will be under microsoft mode.

OSC.IN

A built-in inverter provides oscillation with 32.768 KHz crystal or 3.58MHz

OSC.OUT

resonator.
Several counters used to decrease the frequency of oscillation and create 1200 baud
rate, key-switches debounce and photo-couple sensor scanning clock,etc.

RTS

Positive power input.
The signal is sent by mouse driver from computer to the mouse to select
a mode. During the reset time, EM83702 echoes the selected mode to the RXD line
after the reset pulse signal of the RTS line. RXD will send out CD(H) code if
it is under the microsoft mode. RXD will send out two byte C8(H) code if it is under
the mouse system mode in EM83702.

EM83702

ALL IN ONE MOUSE CONTROLLER

* This specification are subject to be changed without notice.

4.15.1996

RXD

There are 8 or 7 bits in each data byte.
Using parallel-in and serial-out components, the data bytes are shifted out from bit
0 through the high bits. EM83702 will transmit the data while the status of three
keyswitches or the state of the horizontal counter or vertical counter is changed.

Negative power input.

Three key-switches exert seven different combinations totally.

I/O

Both key-pressed and key-released signals will be sent accomplanied with

I/O

horizontal and vertical state. The status of the key-switches will be preserved,
whenever the value of horizontal or vertical counters will present at RXD. And the
debounce interval for both key-press and key-release is 13 ms.
In testing mode, L and M are the outputs of motion detecdor. Using R key can select
the two outputs X1, X2 or Y1,Y2. This feature can help manufacturer to adjust the
phase of four photo-couples for improving the yield.

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

EM83702 is in 1200 baud rate on non-auto speed mode, the system provides 40

transmission cycles per second in microsoft mode to the utmost. In mouse system

mode, the cycles are 24 maxiun. During the scaning period, as long as the photo-
couples change their states, the value of vertical or horizontal counter will increase
or decrease accordingly.

OPT

Whenever OPT is connected to V

, the chip will enter testing mode.

Power.

Symbol

I/O

Function

FUNCTION DESCRIPTIONS

A) Operating Mode

Mouse system mode

Anytime the mouse changes its state, including the key-switches and the photo-couple sensors, EM83702 will
detect the result and transmit to RS-232C. Mouse system transmits the result with five bytes in 1200 baud
rate. Each byte contains 10 bits, one start bit, one stop bit and eight data bits. The first byte represents
the key-switches status. The second byte denote the number counted by the horizontal counter. The third byte
conveys the number accumulated by the vertical counter. If the mouse is moved faster, the photo-couple
sensors detect the "change state" and output the record, excessive horizontal counter will be transported
through the fourth byte, and vertical counter through the fifth byte. Otherwise, the fourth and fifth byte are zero.
Output bytes arrange:

bit

no ......

1st

byte......

R'*

2nd

byte......

3rd

byte......

4th

byte......

5th

byte......

* ` denotes complement

EM83702

ALL IN ONE MOUSE CONTROLLER

* This specification are subject to be changed without notice.

4.15.1996

(B) Microsoft mode

In microsoft mode, the transmission cycle consists of three bytes. Each byte is divided into one start bit, seven
data bits and two stop bit. The first byte contains "L","R" switch status and four bits of the two most sig-
nificant bits in horizontal counter and vertical counter. The next byte represents the value accumulated by
horizontal counter, the last byte is the data of the vertical counter. Notice that "M" key-switch is not active
in the microsoft mode and the vertical data is transmited in 2's complement.
Output byte arrange:

bit

no ......

1st

byte......

V7'

V6'

2nd

byte......

3rd

byte......

V5'

V4'

V3'

V2'

V1'

V0'

Whenever OPT is connected to V

, the chip will enter buyer's testing mode. The X direction output signals

of comparators will present to L and M pin. Pressing "R" key can toggle the output from X direction to Y
direction.

(D) Echo mode

RXD will send out CD(H) code when RTS rise from low to high under microsoft mode. Under mouse
system mode, when RTS rise from low to high, the RXD pin EM83702 will send out two byte C8(H) code.

EM83702

ALL IN ONE MOUSE CONTROLLER

* This specification are subject to be changed without notice.

4.15.1996

DC ELECTRICAL CHARACTERISTICS

( T

= 25

C to 70

C )

Parameter

Sym.

Min. Typ.

Max.

Unit.

Operating voltage

6.5

RTS

Operating current

=5.4V,RTS=V

, 32.768KHz, no load)

Iop

0.6

Operating current

=6.2V,RTS=V

, 32.768KHz, no load)

Iop

Operating current

=5.4V,RTS=V

, 3.58KHz, no load)

Iop

1.6

Operating current

=6.2V,RTS=V

, 3.58KHz, no load)

Iop

RTS operating current

=5.6V,RTS=11V)

RTS

0.6

RTS operating current

=5.6V,RTS=11.8V)

RTS

RXD high output voltage

Irh

2.0

(Vrh=Vrts-2.6V)

RXD low output voltage

Irl

-2.0

(Vrl=Vss+2.6V)

X1,X2,Y1,Y2 low input voltage

Vpl

0.7

X1,X2,Y1,Y2 high input voltage

Vph

1.3

X1,X2,Y1,Y2 input current

Ipi

104

( pull low resistor Vds=1.0V )

RTS high input voltage

Vt+

9.6

RTS low input voltage

Vt-

6.8

Low input voltage , other pins

Vail

1.5

High input voltage , other pins

Vaih

3.5

L,M,R,OPT input current

Imi

18.6

(pull low resistor Vds=5.6V)

RS,OSC.IN,L,M,R,X1, X2,Y1,Y2,OPT

Iil

1.0

input leakage current

( Vin = 0V )

RS,OSC.IN input leakage current

Iih

-1.0

( Vin = 5.6V)

ABSOLUTE MAXIMUM RATINGS

Parameter

Min.

Max.

Unit

Supply voltage

-V

-0.3

7.0

RTS-V

-0.3

Temperature under bias

Storage temperature range

-65

150

Power dissipation

500

* All voltages in above table are compared with V

* All parameters in above table are tested under V

=5.6V.

Part Number EM83702