ELAN EM84510CP, EM84510BP, EM84510AP, EM84510FP, EM84510EP Datasheet

GENERAL DESCRIPTION

The EM84510 Scrolling Mouse Controller is specially designed to control PS/2 mouse device. This single chip
can interface three key-switches four photo-couples plus z-axis direct to 8042 controller.
EM84510 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 traditional mouse, a great number of noises are generated when the grid is partially closed or opened. These
noises are usually mistaken for movement signals by traditional mouse controller and the cursor of the dispaly
screen is thus moved frequently up and down or back and forth. This will consume a great amount of energy.
The EM84510 mouse controller provides noise immunity circuits to eliminat these noise in order to reduce
energy consumption.

FEATURES

• Using 51k ±5% resistor for RC oscillation.

• Compatible with legacy PS/2 mouse.

• Compatible with Microsoft scrolling mouse.

• Built-in noise immunity circuit.

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

• Built-in three step dynamic input impedance.

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

• 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)

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

• The sampilng rate of motion detector is about 65KHz.

• Low power dissipation.

• Package type:
EM84510AP : 16DIP, Photo couples input. (Z/1) EM84510DP: 16DIP, Mechanical input. (Z/1)
EM84510BP : 16DIP, Key-switches input. EM84510EP : 16DIP, Photo couples input. (Z/4)
EM84510CP : 16DIP, Voltage-sensing input. EM84510FP : 16DIP, Mechanical input. (Z/2)

EM84510

PS/2 SCROLLING MOUSE CONTROLLER

PIN ASSIGNMENT

EM84510A/B/C/D/E/FP

VDD

OSC.OUT

Z1
Z2

CLK

DATA

OPT
VSS

* This specification are subject to be changed without notice.

1

16
2
3
4
5
6
7
8

OSCR

15

Y2

14

Y1

13

X2

12

X1

11

L

10

M

9

R

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FUNCTIONAL BLOCK DIAGRAM

EM84510

PS/2 SCROLLING MOUSE CONTROLLER

THREE TYPES SELECTOR

VOLTAGE

SENSOR

Z-AXIS COUNTER

MULTIPLEXER

COMMON

STATUS

SYSTEM CLOCK

GENERATOR

RC

OSCILLATION

KEY-SWITCH

DETECTOR

DATA

DATA

I/O

TIMING

CONTROLLER

CLK

OPT

Z1
Z2

C

D

O

M

E

M

O

X1

X2

Y1

Y2

L

M

R

P
A
R
A
T
O
R

OSC.OUT

D
E
B
O
U
N
C
E

T

T

E

I

C

O

T

N

O
R

OSCR

COMPARATOR

COUNTER

PIN DESCRIPTIONS

Symbol I/O Function

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

When OPT is connected to VDD, EM84510 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.
"1"= VDD, "0"= floating

High duty is about 60us.
OSC.OUT O RC mode oscillation with 51kohm resistor.
OSCR I
CLK I/O Connect to 8042 auxiliary port CLK line.
DATA I/O Connect to 8042 auxiliary port DATA line.
R/M/L I Three key-switches inputs.

200kohm resistor pull low.
X1 I Three step dynamic input impedance.
X2 Use current comparator to measure photo-couples "ON" ,or "OFF".
Y1
Y2
Z1 Z-axis inputs.
Z2 Photo mode: Three step dynamic input impedance. Current comparator input.

Key mode: 200kohm resistor pull low. 7 levels increased by "M" key.

Voltage mode: 200kohm resistor pull low. 7 levels voltage comparator.

Mechanical mode : 13.2kohm resistor pull low.
VSS Negative power.

VDD Power line.

* This specification are subject to be changed without notice.

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FUNCTION DESCRIPTIONS

Legacy PS/2 mouse operating:
(A) Operating mode
There are four operating modes in PS/2 mouse:
a. 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:
(a) Completion code AA & ID code 00.
(b) Set default :

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

b. Stream Mode:

The maximum rate of transfer is the programmed sample rate.

Data report is transmitted if

(a) switch is pressed

(b) movement has been detect

EM84510

PS/2 SCROLLING MOUSE CONTROLLER

c. Remote Mode:

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

d. Wrap Mode:

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

by EM84510.

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 )

* This specification are subject to be changed without notice.

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EM84510

PS/2 SCROLLING MOUSE CONTROLLER

C) PS/2 mouse Data Transmission:

i). EM84510 generates the clocking signal when sending data to and receiving data from the system.

ii). The system requests EM84510 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

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 EM84510 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 EM84510 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, EM84510 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 EM84510
output after EM84510 has started a transmission. If this occurs before the rising edge of the tenth clock,
EM84510 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 EM84510 by holding CLK low until it can service the input
or until the system receives a request to send a response from EM84510.

v). Data Input ( from system to EM84510 ):

System first check if EM84510 is transmitting data. If EM84510 is transmitting, the system can override
the output forcing CLK to an inactive level prior to the tenth clock. If EM84510 transmission is beyond
the tenth clock, the system receives the data. If EM84510 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, EM84510 clocks 11 bits. Following the tenth clock EM84510 checks for
an active level on the DATA line, and if found, force DATA low , and clock once more. If occurs framing
error, EM84510 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 EM84510 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.

* This specification are subject to be changed without notice.

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EM84510

PS/2 SCROLLING MOUSE CONTROLLER

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

iv). EM84510 receives a Resend command ( FE ), it transmit its last packet of data.

v). In the stream mode “Resend” is received by EM84510 following a 3-byte data packet transmission

to the system. EM84510 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.

E). PS/2 Mouse Commands Description:

There are 16 valid commands that transmits between the system and EM84510. 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 EM84510 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

The following describes valid commands:

a). Reset ( FF )

EM84510 operation:

i). Completion the reset.

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

iii). Set default:

sampling rate: 100 reports/s
non-autospeed

* This specification are subject to be changed without notice.

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EM84510

PS/2 SCROLLING MOUSE CONTROLLER

stream mode
2 dots/count
disable

b). Resend ( FE )

i). Any time EM84510 receives an invalid command, it returns a Resend command to the system.

ii). When EM84510 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 EM84510 immediately following a 3-byte data

packet transmission to the system.

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 EM84510.

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

g). Read Device Type ( F2 )

EM84510 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 )

EM84510 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.

* This specification are subject to be changed without notice.

5.30.2001

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