Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

PS/2 MOUSE CONTROLLER

DESCRIPTION

The SC84502 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. SC84502 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 display screen is thus moved

frequently up and down or back and forth. This will consumes a great

amount of energy. The SC84502 PS/2 mouse controller provides

noise immunity circuits to eliminate these noise In order to reduce

energy consumption.

FEATURES

* Being compatible 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 12ms

* Through three key-switches input, SC84502 can exert seven

different output

* The motion detector of the SC84502 could sense 8m/sec

maximum with 200 DPI wheels

DIP-16

DIP-14

ORDERING INFORMATION

SC84502AP

DIP-14 PACKAGE

DIP-16 PACKAGE

SC84502BP

APPLICATIONS

* Optical mouse or pen-mouse

* Mechanical mouse or pen-mouse

* Optomechanical mouse or pen-mouse

* Mechanical track ball

* Optomechanical track ball

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

PIN CONFIGURATIONS

SC84

502BP

VDD

OSC OUT

CLK

DATA

VSS

OSCR

VDD

VSS

OSC OUT

CLK

DATA

OSCR

84502

BLOCK DIAGRAM

( Refer to SC84502BP )

COUNTER

DATA

I/O

CTO

UNCE

I
S

I
MMUNTY

TIMING

CONTROLLER

SYSTEM

CLOCK

GENERATOR

OSCR

OSC OUT

DATA

CLK

MMA

DC ELECTRICAL CHARACTERISTICS

(Tamb=25~70

�

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Operating Voltage

4.5

5.5

Operating Current

Iop

No Load

1.2

X1,X2,Y1,Y2

Low Input reference current

Ipl

�

X1,X2,Y1,Y2

High Input reference current

Iph

106

�

(to be continued)

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

(continued)

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Schmitt trigger input, Ipl=76

�

0.8

1.2

Comparator input, Ipl=80

�

0.8

1.2

X1,X2,Y1,Y2 input current

Comparator input, Ipl=500

�

1.5

2.1

CLK, DATA positive-going

threshold voltage

Vt+

3.2

3.8

CLK, DATA negative-going

threshold voltage

Vt-

1.2

1.9

Low Input Voltage, Other Pins

Vail

1.5

High Input Voltage, Other Pins

Vaih

3.5

L,M,R Input Current

Imi

Pull Up Resistor, Vin=5V

16.6

�

PS/2 mouse mode

DATA,CLK input Current

Idc

Vin = 0V

0.56

1.86

PS/2 mouse mode

DATA,CLK low output Voltage

Vprl

Iprl = -2 mA

0.4

L,M,R,X1,X2,Y1,Y2

Input Leakage Current

Iil

Vin = 0V

1.0

�

Note: 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.

AC ELECTRICAL CHARACTERISTICS

( Tamb = 0 ~ 70

�

Parameter

Symbol

Min

Typ

Max

Unit

Oscillating Frequency

Fosc

34.3-10%

34.3

34.3+10%

kHz

Key Debounce

Tkd

Rising Edge Crossed Width Fosc=35 kHz

14.3

�

Falling Edge Crossed Width Fosc=35 kHz

14.3

�

Mouse CLK Active Time

Tmca

42.9

�

Mouse CLK Inactive Time

Tmci

42.9

�

Time that Mouse Sample DATA from CLK rising Edge

Tmdc

14.3

�

System CLK Active Time

Tsca

42.9

�

System CLK Inactive Time

Tsci

42.9

�

Time from DATA Transition to Falling Edge of CLK

Tsdc

14.3

�

Time from rising Edge of CLK to DATA Transition

Tscd

28.6

�

Time to mouse Inhibit after the 11th CLK to

ensure mouse does not start another Transmission

Tpi

�

Note: The AC timings are measured under using 35kHz system clock signal.

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

X1, X2, Y1, Y2 INPUT IMPEDANCE

1.0

2.0

3.0

4.0

5.0

UNIT:K

MAX.

TYP.

MIN.

7.0

8.0

9.0

6.0

2.0

3.0

4.0

1.0

10.0

15.0

16.0

12.0

13.0

14.0

11.0

INPUT VOLTAGE

PIN DESCRIPTION

(refer to SC84502BP)

Pin No. Pin Name

I/O

Description

Positive Power Supply.

X, Y inputs:

Floating: Comparator input.

GND: Schmitt trigger input.

Short to OSC OUT: Testing Mode.

No Connection

OSCOUT

Clock output.

CLK

I/O

8042 auxiliary port CLK line.

DATA

I/O

8042 auxiliary port DATA line.

Negative Power Supply

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

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

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 12ms.

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

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

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

OSCR

50k

�

5% pull low for 35kHz oscillation

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

FUNCTION DESCRIPTIONS

1. 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.

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:

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

SC84502.

2. 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:

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

Byte

Bit

Description

Left button status; 1 = pressed

Right button status; 1 = pressed

Middle button status; 1 = pressed

Reserve

X data sign; 1 = negative

Y data sign; 1 = negative

X data overflow; 1 = overflow

Y data overflow; 1 = overflow

0-7

X data(D0 ~ D7)

0-7

Y data(D0 ~ D7)

3.PS/2 MOUSE DATA TRANSMISSION

i) SC84502 generates the clocking signal when sending data to and receiving data from the system.

ii) The system requests SC84502 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:

Bit

Function

Start bit(always 0)

2 ~ 9

Data bits(D0 ~D7)

Parity bit(odd parity)

Stop bit (always 1)

iv) Data Output (data from SC84502 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 SC84502 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, SC84502 check for line contention by checking for an inactive level on CLK at

intervals not to exceed 100

�

sec. Contention occurs when the system lowers CLK to inhibit SC84502

output after SC84502 has started a transmission. If this occurs before the rising edge of the contention

does not occur by the tenth clock, the transmission is complete.

Following a transmission, the system inhibits SC84502 by holding CLK low until it can service the input or

until the system receives a request to send a response from SC84502.

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

v) Data Input (from system to SC84502)

System first check if SC84502 is transmitting data. If SC84502 is transmitting, the system can override the

output forcing CLK to an inactive level prior to the tenth clock. If SC84502 transmission is beyond the tenth

clock, the system receives the data. If SC84502 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 100m 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, SC84502 clocks 11 bits. Following the tenth clock SC84502 checks for an active level on the

DATA line, and if found, force DATA low , and clock once more. If occurs framing error, SC84502 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 SC84502 to response

before sending its next output.

4. 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) SC84501 receives a Resend command ( FE ), it transmit its last packet of data.

In the stream mode "Resend" is received by SC84502 following a 3-byte data packet transmission to the

system. SC84502 resend the 3-byte data packet prior to clearing the counter.

vi) A response is sent within 25 ms if

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.

5. PS/2 MOUSE COMMANDS DESCRIPTION

There are 16 valid commands that transmits between the system and SC84502. 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:

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

Hex Code

Command

SC84502 echo code

Reset

FA, AA, 00

Resend

XX, (XX, XX)

Set Default

Disable

Enable

F3, XX

Set Sampling Rate

FA, FA

Read Device Type

FA, 00

Set Remote Mode

Set Wrap Mode

Reset Wrap Mode

Read Data

FA, XX, XX, XX

Set Stream Mode

Status Request

FA, XX, XX, XX

E8, XX

Set Resolution

EA, FA

Set Autospeed

Reset Autospeed

The following describes valid commands:

a). Reset ( FF )

SC84502 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 SC84502 receives an invalid command, it returns a Resend command to the system.

ii). When SC84502 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 SC84502 immediately following a 3-byte data

packet transmission to the system.

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

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 SC84502.

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

10/sec

20/sec

40/sec

60/sec

80/sec

100/sec

200/sec

g). Read Device Type (F2)

SC84502 always echoes "FA, 00 " following this command.

h). Set Remote Mode (F0)

Data values 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)

SC84502 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 SC84502 in stream mode.

m). Status Request (E9)

When this command is issued by the system, SC84502 respond with a 3-byte status report as follows:

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

Byte

Bit

Description

1=Right button pressed

1=Middle button pressed

1= Left button pressed

Reserved

0=Normal speed, 1=Autospeed

0=Disabled, 1=Enabled

0=Stream mode, 1=Remote mode

Reserved

0�7

Current resolution setting (D0-D7)

0-7

Current sampling rate (D0-D7)

n). Set Resolution ( E8,XX )

SC84502 provides four resolutions selected by the second byte of this command as follows:

Second Byte XX

Resolution

8 dot/count

4 dot/count

2 dot/count

1 dot/count

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

Output

N (

2.0*N

p). Reset Autospeed ( E6 )

This command restore normal speed.

6.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.

Silan
Semiconductors

SC84502

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

TIMING DIAGRAM

X1(Y1)

X2(Y2)

CLK

DATA

CLK

DATA

Inhibit

Start

Bit

Bit0-Bit7

Parity

Bit

Line

Control

Bit

Stop

Bit

Start

Bit

Bit0-Bit7

Parity

Bit

Stop

Bit

Tscl

Tsca

Tscd

Tsdc

Tpi

Tmdc

Tmca

Tmci

1st

CLK

2rd

CLK

9th

CLK

10th
CLK

11th
CLK

1st

CLK

2nd

CLK

10th
CLK

11th
CLK

(2) PS/2 Mouse

(B) Sending Data

(A) Receiving Data

(1) Photo-couples pulse width

AC TIMING POINT

-2.6

+0.4

+1.6

+0.8

-0.8

L, M, R PIN

CLK, DATA PIN

Input:

X1, X2, Y1, Y2 PIN

Output:

DATA
CLK PIN

(PS/2 mouse mode)

Электронный компонент: SC84502BP