ELAN EM83812FP, EM83812EP, EM83812DP, EM83812CP, EM83812BP Datasheet

ALL-INONE PLUG & PLAY SCRLLING SERIAL MOUSE CONTROLLER

GENERAL DESCRIPTION

The EM83812 PnP Scrolling Mouse Controller is specially designed to control serial mouse device.
This single chip can interface three key-switches and 4 X-Y photo-couples plus Z-axis directly to RS-232C.
There are four types Z-axis inputs used to implement scrolling mouse functionality.

FEATURES

• Using 50kΩ ±1% resistor for RC oscillation.

• Compatible with Microsoft serial scrolling mouse.

• 100 bytes PnP ID code could be filled by code layer.

• Built-in noise immunity circuit.

• The sampiling rate of motion detector is up to 65KHz.

• Built-in three zener diodes : one in VDD to VSS, two in RTS to VDD.

• CMOS push-pull RXD output.

• Built-in current comparator for photo-couples input.

• Built-in three step dynamic input impedance.

• Three key-switches and four photo-couples inputs.

• RTS debouncing circuit included.

• Photo couple test mode included.

• Low power dissipation.

• Six types Z direction input:

1. Photo couples input. (Z/1) 4. Mechanical input. (Z/1)

2. Key-switches input. 5. Photo couples input. (Z/4)

3. Voltage-sensing input. 6. Mechanical input. (Z/2)

• Package type:
EM83812AP : 16DIP, Photo couples input. (Z/1) EM83812DP: 16DIP, Mechanical input. (Z/1)
EM83812BP : 16DIP, Key-switches input. EM83812EP : 16DIP, Photo couples input. (Z/4)
EM83812CP : 16DIP, Voltage-sensing input. EM83812FP : 16DIP, Mechanical input. (Z/2)

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APPLICATION

• Serial PnP scrolling mouse.

PIN ASSIGNMENT

EM83812A/B/C/D/E/FP

V

DD

Z1
Z2

RTS

RXD

OPT
VSS

1
2
3
4
5
6
7
8

OSC.OUT

* This specification are subject to be changed without notice.

16

OSCR

15

Y2

14

Y1

13

X2

12

X1

11

L

10

M

9

R

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ALL-INONE PLUG & PLAY SCRLLING SERIAL MOUSE CONTROLLER

FUNCTIONAL BLOCK DIAGRAM

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EM83812

OPT

Z1
Z2

C

D

O

M

E

M

X1
X2
Y1
Y2

L

M

R

O

P

T

A

I

R

O

A

N

T

O

R

D
E
B
O
U
N
C
E

OSCR

OSC.OUT

T
E
C
T
O
R

THREE TYPES SELECTOR

COMPARATOR

Z-AXIS COUNTER

COUNTER

SYSTEM CLOCK

GENERATOR

OSCILLATION

VOLTAGE

SENSOR

COMMAND

STATUS

RC

KEY-SWITCH

DETECTOR

MULTIPLEXER

RXD

RTS

DATA

I/O

TIMING

CONTROLLER

PIN DESCRIPTIONS

Symbol I/O Function

OPT I/O INPUT: 200kohm pull low to VSS.

When OPT is connected to VDD, EM84520 will enter test mode. In test mode,
L will be the output of X1,while M will be the output of X2. Toggling R key can
change these output to be Y1,Y2 or Z1,Z2 respectively.
OUTPUT: 2kHz Z-axis LED driving source with A/D/E/F version.
"1"= VDD, "0"= floating
High duty is about 60us.

OSC.OUT O The RC oscillation clock output. Or 3mA sink current output for X, Y photo

emitters.

OSCR I Connect 50kΩ±1% precise resistor for oscillation.
RTS I/O ±12V signal with 10mA driving. Used as PnP ID code output trigger signal

from 10w (-12V) to high (+12V) while under normal operating. RTS will keep on
±12V driving.

RXD I/O One report contains 4 data bytes, 7 data bits without parity in the data byte.

The data byte is sgifted out from LSB through MSB, started by start bit and ended
by stop bit. The RXD signal swing between +6V and -6V.

R I Three key-switches inputs. 200kΩ resistor pull low.
M I/O In Z-axis key mode, M key toggling can change the scrolling speed from low to
L I/O high.
X1 I Three step dynamic input impedance. If OSC.OUT is not connected to LEDs, the
X2 I dynamic input impedance will be off.
Y1 I Use current comparator to measure photo-couples "ON", or "OFF".
Y2 I
Z1 I Z-axis input.
Z2 I Photo mode : Three steps dynamic input impedance. Current comparator input.

Key mode : 200 kΩ resistor pull low. 7 levels increased by "M" key.
Voltage mode : 200 kΩ resistor pull low. 7 levels voltage comparator.
Mechanical mode : 13.2kΩ resistor pull low. Current comparator input.

VSS Negative power.
VDD Power line.

* This specification are subject to be changed without notice.

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ALL-INONE PLUG & PLAY SCRLLING SERIAL MOUSE CONTROLLER

FUNCTION DESCRIPTIONS

(I) Serial Scrolling Mouse :

In Microsoft mode, the transmission cycle consists of four bytes in one report. Each byte contains one start
bit, 7 data bits and two stop bits. The first byte contains "L", "R" key status and four bits of the two most
significant bits in horizontal counter and vertical counter. The second byte represents the value accumulated
by horizontal counter, the third byte is the data of the vertical counter. The last byte contains "M" key status
and Z-axis value. The vertical data is transmitted in 2's complement.

Output byte arrange

Bit no. ...... 654321 0

1st byte ...... 1 L R V7' V6' H7 H6

2nd byte .... 0 H5 H4 H3 H2 H1 H0

3rd byte .... 0 V5' V4' V3' V2' V1' V0'

4th byte .... 0 0 M Z3 Z2 Z1 Z0

Plug & Play ID code

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When RTS input from low to high, EM84520 will send a string ID code. Customer can specify the contains
of the code area and the total lenth below 100 bytes by changing the code layer.

Field Name Length Field Data Description

Other ID <17 4D, 5A, 40, 00, 00, 00 ID for legacy
Begin ID 1 08 Begin PnP ID
PnP Revision 2 01, 24 Version 1.00
EISA ID 3 25, 2D, 23 EMC
Product ID 4 10, 10, 10, 11 0001
Serial Number 9 3C None provided
Class ID <34 3C, 2D, 2F, 35, 33, 25 Mouse Class
Driver ID <42 3C, 30, 2E, 30, 10 26, 10, 21 PnP0F0A
User Name <42 3C, 25, 2D, 23, 00, 33, 23, 32, EMC SCROLLING

2F, 2C, 2C, 29, 2E, 27, 00, 33, SERIAL MOUSE
25, 32, 29, 21, 2C, 00, 2D, 2F,

35, 33, 25
Check sum 2 21, 15 2 bytes checks um
End PnP 1 09 End PnP ID

(II). Z-axis Input Function :

(a) Photo couples input : Z-axis counter accumulates the Z1, Z2 phase changed by movement.

(b) Key-switches input : Pressing Z1, Z2 will start to fill the Z-axis counter with the value beginning at one.

Toggling "M" key can increase the value any time by one. The limit value is ±7.

(c) The relationship between the value and the transmission rate as follows :

* This specification are subject to be changed without notice.

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EM83812

ALL-INONE PLUG & PLAY SCRLLING SERIAL MOUSE CONTROLLER

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Value Rate per second

1 2.7
2 6.4
3 9.2
4 12.8
515
618
720

(d) Voltage-sensing mode : There are 7 voltage levels in Z1, Z2 input. The transmission table is the same as

key-switches mode. The relationship between the value of Z-axis counter and the voltage as folllows :

Value Voltage

01V↓
1 1.0V-1.6V
2 1.6V-2.2V
3 2.2V-2.8V
4 2.8V-3.4V
5 3.4V-4.0V
6 4.0V-4.6V

74.6V↑

Under V

=5V condition.

DD

(e) Mechanical mode : The same as optical wheel mode.

* This specification are subject to be changed without notice.

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