EM84510
PS/2 SCROLLING MOUSE CONTROLLER
1
* This specification are subject to be changed without notice.
5.30.2001
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)
PIN ASSIGNMENT
V
DD
OSC.OUT
Z1
Z2
CLK
DATA
OPT
VSS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
OSCR
Y2
Y1
X2
X1
L
M
R
EM84510A/B/C/D/E/FP
EM84510
PS/2 SCROLLING MOUSE CONTROLLER
2
* This specification are subject to be changed without notice.
5.30.2001
FUNCTIONAL BLOCK DIAGRAM
PIN DESCRIPTIONS
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.
Symbol
I/O
Function
Z1
Z2
OPT
X1
X2
Y1
Y2
L
M
R
OSCR
OSC.OUT
C
O
M
P
A
R
A
T
O
R
M
O
T
I
O
N
D
E
T
E
C
T
O
R
D
E
B
O
U
N
C
E
COUNTER
COMMON
STATUS
SYSTEM CLOCK
GENERATOR
RC
OSCILLATION
MULTIPLEXER
DATA
I/O
TIMING
CONTROLLER
COMPARATOR
VOLTAGE
SENSOR
KEY-SWITCH
DETECTOR
Z-AXIS COUNTER
THREE TYPES SELECTOR
DATA CLK
EM84510
PS/2 SCROLLING MOUSE CONTROLLER
3
* This specification are subject to be changed without notice.
5.30.2001
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
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 )
EM84510
PS/2 SCROLLING MOUSE CONTROLLER
4
* This specification are subject to be changed without notice.
5.30.2001
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 100
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.
EM84510
PS/2 SCROLLING MOUSE CONTROLLER
5
* This specification are subject to be changed without notice.
5.30.2001
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
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