Datasheet EM84502BP, EM84502BM, EM84502AP, EM84502AM Datasheet (ELAN)

GENERAL DESCRIPTION

The EM84502 Mouse Controller is specially designed to control PS/2 mouse device.This single chip can
interface three key-switches and four photo-couples direct to 8042. EM84502 can receive command and echo
status or data format which are compatible with IBM PS/2 mode mouse. Key debouncing circuit is provided
to prevent false entry and improve the accuracy.
In the conventional mouse, a great number of noises are generated when the grid is partially closed or opened.
These noise are usually mistaken for movement signals by conventional mouse controller and the cursor of the
dispaly screen is thus moved frequently up and down or back and forth. This will consumes a great amount of
energy.The EM84502 PS/2 mouse controller provides noise immunity circuits to eliminate these noise
in order to reduce energy consumption.

FEATURES

• Being compatiable with PS/2 mouse mode.

• Built-in noise immunity circuit.

• Low power dissipation.

• RC oscillation.

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

• Both key-press and key-release debounce interval 12 ms.

• Through three key-switches input, EM84502 can exert seven different output.

• The motion detector of the EM84502 could sense 8 m/sec maximun with 200 DPI wheels.

EM84502

PS/2 MOUSE CONTROLLER

PS/2 MOUSE CONTROLLER

EM84502

APPLICATIONS

• Optical mouse or pen-mouse.

• Mechanical mouse or pen-mouse.

• Optomechanical mouse or pen-mouse.

• Mechanical track ball.

• Optomechanical track ball.

PIN ASSIGNMENT

EM84502AP

V

DD

OP

OSC.OUT

CLK

DATA

VSS

R

EM84502BP

V

DD

OP
NC
NC

OSC.OUT

CLK

DATA

VSS

EM84502AM

1
2
3
4
5
6
7

OSCR

14

Y2

13

Y1

12

X2

11

X1

10

L

9

M

8

V

OSC.OUT

CLK

DATA

VSS

OP

DD

1
2
3
4
5
6
7

R

OSCR

14

Y2

13

Y1

12

X2

11

X1

10

L

9

M

8

EM84502BM*

1

16
2
3
4
5
6
7
8

OSCR

15

Y2

14

Y1

13

X2

12

X1

11

L

10

M

9

R

V

OP
NC
NC

OSC.OUT

CLK

DATA

VSS

DD

1

16
2
3
4
5
6
7
8

OSCR

15

Y2

14

Y1

13

X2

12

X1

11

L

10

M

9

R

* (Under developed)

* This specification are subject to be changed without notice.

8.3.2001

1

FUNCTIONAL BLOCK DIAGRAM

T

OP

D

X1

X2

Y1

Y2

L

M

R

OSCR

OSC OU

I

E

M

M

N

T

M

O

O

E

U

T

I

C

N

I

S

T

IT

O

E

O

Y

N

R

D
E
B
O
U
N
C
E

COUNTER

TIMING

CONTROLLER

SYSTEM

CLOCK

GENERATOR

D
A
T
A

PIN DESCRIPTIONS

Symbol I/O Function

C
O
N
V
E
R
T
E
R

DATA

PS/2 MOUSE CONTROLLER

EM84502

D

C

E

O

C

M

O

M

D

A

E

N

R

D

I/O

DATA
CLK

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.

* This specification are subject to be changed without notice.

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2

2). Set default:
sampling rate: 100 reports/s
non-autospeed
stream mode
2 dot/count
disable

ii). Stream Mode:

The maximum rate of transfer is the programmed sample rate.
Data report is transmitted if

1). switch is pressed

2). movement has been detect

iii). Remote Mode:

Data is transmitted only in response to a Read Data command.

iv). Wrap Mode:

PS/2 MOUSE CONTROLLER

EM84502

Any byte of data sent by the system, except hex EC ( Reset wrap mode ) or hex FF ( Reset ), is returned
by EM84502.

B). PS/2 Mouse Data Report:

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

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

iii). Data report format:

Byte Bit Description

1 0 Left button status; 1 = 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 )

C) PS/2 mouse Data Transmission:

i). EM84502 generates the clocking signal when sending data to and receiving data from the system.

ii). The system requests EM84502 receive system data output by forcing the DATA line to an inactive

level and allowing CLK line to go to an active level.

iii). Data transmission frame:

* This specification are subject to be changed without notice.

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PS/2 MOUSE CONTROLLER

Bit Function

1 Start bit ( always 0 )
2-9 Data bits ( D0 - D7 )
10 Parity bit ( odd parity )
11 Stop bit ( always 1 )

iv). Data Output ( data from EM84502 to system ):

If CLK is low ( inhibit status ) , data is no transmission.

If CLK is high and DATA is low ( request-to-send ), data is updated. Data is received from the system
and no transmission are started by EM84502 until CLK and DATA both high. If CLK and DATA are both
high, the transmission is ready. DATA is valid prior to the falling edge of CLK and beyond the rising edge
of CLK. During transmission, EM84502 check for line contention by checking for an inactive level on CLK
at intervals not to exceed 100u sec. Contention occurs when the system lowers CLK to inhibit EM84502
output after EM84502 has started a transmission. If this occurs before the rising edge of the tenth clock,
EM84502 internal store its data in its buffer and returns DATA and CLK to an active level. If the contention
does not occur by the tenth clock, the transmission is complete.
Following a transmission, the system inhibits EM84502 by holding CLK low until it can service the input
or until the system receives a request to send a response from EM84502.

EM84502

v). Data Input ( from system to EM84502 ):

System first check if EM84502 is transmitting data. If EM84502 is transmitting, the system can override
the output forcing CLK to an inactive level prior to the tenth clock. If EM84502 transmission is beyond
the tenth clock, the system receives the data. If EM84502 is not transmitting or if the system choose to
override the output, the system force CLK to an inactive level for a period of not less than 100µ sec while
preparing for output. When the system is ready to output start bit (0), it allows CLK go to active level. If
request-to-send is detected, EM84502 clocks 11 bits. Following the tenth clock EM84502 checks for
an active level on the DATA line, and if found, force DATA low , and clock once more. If occurs framing
error, EM84502 continue to clock until DATA is high, then clocks the line control bit and request a
Resend. When the system sends out a command or data transmission that requires a response, the system
waits for EM84502 to response before sending its next output.

D). PS/2 Mouse Error Handling:

i). A Resend command ( FE ) following receipt of an invalid input or any input with incorrect parity.

ii). If two invalid input are received in succession, an error code of hex FC send to the system.

iii). The counter accumulators are cleared after receiving any command except “Resend”.

iv). EM84501 receives a Resend command ( FE ), it transmit its last packet of data.

v). In the stream mode “Resend” is received by EM84502 following a 3-byte data packet transmission

to the system. EM84502 resend the 3-byte data packet prior to clearing the counter.

vi). A response is sent within 25 ms if

* This specification are subject to be changed without notice.

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PS/2 MOUSE CONTROLLER

a). The system requires a response
b).An error is detected in the transmission

vii). When a command requiring a response is issued by the system ,another command should not be issue

until either the response is received or 25ms has passed.

E). PS/2 Mouse Commands Description:

There are 16 valid commands that transmits between the system and EM84502. The “FA” code is always the
first response to any valid input received from the system other than a Set Wrap Mode or Resend command.
The following table list the commands:

Hex Code Command EM84502 echo code

FF Reset FA,AA,00
FE Resend XX,(XX,XX)
F6 Set Default FA
F5 Disable FA
F4 Enable FA
F3,XX Set Sampling Rate FA,FA
F2 Read Device Type FA,00
F0 Set Remote Mode FA
EE Set Wrap Mode FA
EC Reset Wrap Mode FA
EB Read Data FA,XX,XX,XX
EA Set Stream Mode FA
E9 Status Request FA,XX,XX,XX
E8,XX Set Resolution FA,FA
E7 Set Autospeed FA
E6 Reset Autospeed FA

EM84502

The following describes valid commands:

a). Reset ( FF )

EM84502 operation:

i). Completion the reset.

ii). Transmitted FA,AA,00 to the system.

iii). Set default:

sampling rate: 100 reports/s
non-autospeed
stream mode
2 dots/count
disable

b). Resend ( FE )

i). Any time EM84502 receives an invalid command, it returns a Resend command to the system.

ii). When EM84502 receives a Resend command, it retransmits its last packet of data. If the last packet was

a Resend command, it transmits the packet just prior to the Resend command.

iii). In stream mode, if a Resend command is received by EM84502 immediately following a 3-byte data

packet transmission to the system.

* This specification are subject to be changed without notice.

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PS/2 MOUSE CONTROLLER

c). Set Default ( F6 )

The command reinitializes all conditions to the power-on defaults.

d). Disable ( F5 )

This command is used in the stream mode to stop transmissions from EM84502.

e). Enable ( F4 )

Begins transmissions, if in stream mode.

f). Set Sampling Rate ( F3,XX )

In the stream mode, this command sets the sampling rate to the value indicated by byte hex XX,
shown in following:

Second byte XX Sample Rate

0A 10/sec
14 20/sec

28 40/sec
3C 60/sec
50 80/sec
64 100/sec
C8 200/sec

EM84502

g). Read Device Type ( F2 )

EM84502 always echoes “ FA,00 “ following this command.

h). Set Remote Mode ( F0 )

Data value are reported only in response to a Read Data command.

i). Set Wrap Mode ( EE )

Wrap mode remains until Reset ( FF ) or Reset Wrap Mode( EC ) is received.

j). Reset Wrap Mode ( EC )

EM84502 returns to the previous mode of operation after receiving this command.

k). Read Data ( EB )

This command is executed in either remote or stream mode. The data is transmitted even if there has been
no movement since the last report or the button status is unchanged. Following a Read Data command,
the registers are cleared after a data transmission.

l). Set Stream Mode ( EA )

This command sets EM84502 in stream mode.

m). Status Request ( E9 )

When this command is issued by the system, EM84502 respond with a 3-byte status report as follows:

Byte Bit Description

1 0 1 = Right button pressed

1 1 = Middle button pressed
2 1 = Left button pressed

* This specification are subject to be changed without notice.

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PS/2 MOUSE CONTROLLER

3 Reserved
4 0 = Normal speed, 1 = Autospeed
5 0 = Disabled, 1 = Enabled
6 0 = Stream mode, 1 = Remote mode

7 Reserved
2 0-7 Current resolution setting ( D0 - D7 )
3 0-7 Current sampling rate ( D0 - D7 )

n). Set Resolution ( E8,XX )

EM84502 provides four resolutions selected by the second byte of this command as follows:

Second Byte XX Resolution

00 8 dot/count

01 4 dot/count

02 2 dot/count

03 1 dot/count

EM84502

o). Set Autospeed ( E7 )

At the end of a sample interval in the stream mode, the current X and Y data values are converted new values.
The sign bits are not involved in this conversion. The conversion is only in stream mode. The relationship
between the input and output count follows:

Input Ouput
00
11

21
33
46
59
N(≥6 ) 2.0*N

p).Reset Autospeed ( E6 )

This command restore normal speed.

F) Testing mode

Whenever OPT is connected to OSC OUT, 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.

ABSOLUTE MAXIMUM RATINGS

Parameter Sym. Ratings Unit

Temperature under bias T
Storage temperature range T
Input voltage V
Output voltage V

OPR
STR

IN

O

* This specification are subject to be changed without notice.

0~70 °C

-65~150 °C

-0.3~6.0 V

-0.3~6.0 V

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PS/2 MOUSE CONTROLLER

DC ELECTRICAL CHARACTERISTICS (TA=25°C to 70°C)

Parameters Sym. Min. Typ. Max. Unit

EM84502

Operating voltage V
Operating current (no load) I
X,X2,Y1,Y2 low input reference current I
X,X2,Y1,Y2 high input reference current I
X,X2,Y1,Y2 input current V

DD

Op

PL

Ph

PI

4.5 5 5.5 V

- - 1.2 mA

70 - - µA

- - 106 µA

0.8 - 1.2 V

Schmitt trigger input (76µA)
X,X2,Y1,Y2 input current V

PI

0.8 - 1.2 V

Comparator input (80µA)
X,X2,Y1,Y2 input current V

PI

1.5 - 2.1 V

Comparator input (500µA)
CLK, DATA postive-going Vt+ 3.2 - 3.8 V

threshold voltage
CLK, DATA negative-going Vt - 1.2 - 1.9 V

threshold voltage
Low input voltage, other pins Vail - - 1.5 V
High input voltage, other pins Vaih 3.5 - - V
L, M, R input current Imi 16.6 - 50 µA
(pull low resistor Vin=5V)
PS/2 mouse mode DATA, CLK input Current Idc 0.56 - 1.86 mA
(pull up resistor) (VIN=0V)
PS/2 mouse mode DATA, CLK low output voltage Vprl - - 0.4 V

(Iprl=-2mA)

L, M, R, X1, X2, Y1, Y2 input leakage current Iil 0 - 1.0 µA

(Vin=0V)

* All voltages in above table are compared with VSS.
* All parameters in above table are tested under VDD=5V.
* CLK & DATA output gates are open drains that connect to pull up resistors.
* X1, X2,Y1,T2 Input Impedance

MAX.

TYP.

MIN.

16.0K

15.0K

14.0K

13.0K

12.0K

11.0K

10.0.K

9.0K

8.0K

7.0K

6.0K

5.0K

4.0K

3.0K

2.0K

1.0K

0

10.0M

1.0

2.0
VOLTS (LIN)

3.0

* This specification are subject to be changed without notice.

4.0

5.0

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PS/2 MOUSE CONTROLLER

AC ELECTRICAL CHARACTERISTICS (TA=0°C to 70°C)

Parameters Sym. Min. Typ. Max. Unit

Oscillating Frequency Fosc 37.5-10% 37.5 37.5+10% KHz
Key Debounce Tkd - 12 - ms
Rising Edge Crossed Width Fosc=35 KHz Tr 14.3 - - us
Falling Edge Crossed Width Fosc=35 KHz Tf 14.3 - - us
Mouse CLK Active Time Tmca - 42.9 - us
Mouse CLK Inactive Time Tmci - 42.9 - us

Mouse Sample DATA from Tmdc - 14.3 - us
CLK rising Edge

System CLK Active Time Tsca - 42.9 - us
System CLK Inactive Time Tsci - 42.9 - us
Time from DATA Transition to Falling Edge of CLK Tsdc - 14.3 - us
Time from rising Edge of CLK to DATA Transition Tscd - 28.6 - us

Time to mouse Inhibit after the 11th CLK to Tpi 0 - 50 us
ensure mouse does not start another Transmission

EM84502

PS. The AC timings are measured under using 35 KHz system clock signal.

TIMING DIAGRAM

(1) Photo-couples pulse width :

X1 (Y1)

X2 (Y2)

10th

CLK

Tf

11th

CLK

Stop

Bit

(2) PS/2 Mouse

(A) Receiving DATA

CLK

DATA

Inhibit

><

Tmca

><

Tmdc

Start

Bit

Tr

1st

CLK

2nd

CLK

9th

CLK

><

Tmci

• • • • • • • • • • • •• • • • • • •
Bit0 -Bit7

Parity

Bit

• • • • •

Line

Control

Bit

* This specification are subject to be changed without notice.

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9

(B) Sending DATA

PS/2 MOUSE CONTROLLER

EM84502

1st

CLK

2nd

CLK

CLK

DATA

><

Tsci

><

Tsdc

><

Tscd

><

Tsca

• • • • • • • • • • • •• • • • •

Start

Bit

Bit0 -Bit7

AC Timing point:

Output:

DATA,
CLK PIN (PS/2 mouse mode)

Input:

X1,X2,Y1,Y2 PIN

CLK, DATA PIN

L,M,R PIN

EM84502 I/O pin equivalent circuit :
R,M,L : DATA :

VDD-2.6

10th

CLK

Parity

Bit

11th

CLK

><

Tpi

Stop

Bit

+0.4

V

SS

48.4 µA

+1.6V

39.6 µA

V

SS

VDD-0.8
VSS+0.8

V

DD

V

SS

• • • • • • • • • • •

• • • • • • • • •

V

CC

(R,M,L)

(R,M,L)

INTERNAL SIGNAL

PS2 MOUSE ENABLE

DATA OUTPUT SIGNAL

CLK : X1,X2,Y1,Y2 :

X1,X2,Y1,Y2

V

CC

V

DD

+

4

-

PS2 MOUSE ENABLE

CLK OUTPUT SIGNAL

CLK INPUT SIGNAL

V

CC

CLK

DATA INPUT SIGNAL

13.2K

12.5K

V

DD

13.2K

30K

12.5K

V

CC

DATA

-

+

V

DD

80µA

PHASE DIGITAL SIGNAL

* This specification are subject to be changed without notice.

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APPLICATION CIRCUIT

PS/2 MOUSE CONTROLLER

EM84502

+5V

10µf

510

510

13

Y2

12

Y1

1

PS/2 MOUSE ONLY

DD

V

EM84501

OP

2

OSC.DR

14

11

3

30K

10

9

X2

X1

EM84502A

OSC.OUT

CLK

5

4

8

L

DATA

M

7

R

SS

V

6

* This specification are subject to be changed without notice.

CLK

DATA

GROUND

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PAD DIAGRAM

CS

VDD

PS/2 MOUSE CONTROLLER

EM84502

OSCR

OSCOUT

RTSCK

3

4

Chip Size : 1500 µm x 1310 µm (EL5741)

1214

(0,0)

13

12

Y2
Y1

EM84502

11

65

6

GND

RXDBDAT

GND

7

8

R

M

10

9

L

X2
X1

Pad No. Sym. X Y

1V

DD

-204.6 509.4
2 CS -385.9 512.6
3 OSCOUT -596.3 -175.7
4 RTSCK -586.7 -384.8
5 RXDBDAT -426.4 -487.9
6 GND -265.6 -487.9
6 GND -143.8 -510.9
7 R 63.9 -508.7
8 M 235.3 -508.7
9 L 407.1 -508.7

10 X1 587.4 -453.2
11 X2 587.4 -332.6
12 Y1 587.4 374.1
13 Y2 587.4 494.6
14 OSCR 409.6 512.6

* This specification are subject to be changed without notice.

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14 PDIP

PS/2 MOUSE CONTROLLER

EM84502

E1

1

D

A

A1

L1

L

B

e

B1

Symbol

15°(4X)

F

E1

eB

15°(2X)

C

5°(2X)

ϑ

Inches Milimeters

MIN. TYP. MAX. MIN. TYP. MAX.

A - .130 - - 3.302 -

A1 .059 .060 .061 1.499 1.524 1.549

B - .018 - - 0.457 -

B1 - .060 - - 1.524 -

C - .010 - - 0.254 ­D .740 .750 .760 18.796 19.050 19304

E1 .259 .260 - 6.579 6.604 -

F .290 .300 .310 7.366 7.620 7.874

L - .130 - - 3.302 -

L1 - .020 - - 0.506 -

e - .100 - - 2.540 -

eB .345 .355 .365 8.763 9.017 9.271

ϑ 0° 7.5° 15° 0° 7.5° 15°

* This specification are subject to be changed without notice.

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