EM85000 Datasheet, PDF (5/9 Pages) ELAN Microelectronics Corp – APPLE DESKTOP BUS MOUSE CONTROLLER

EM85000
APPLE DESKTOP BUS MOUSE CONTROLLER
3. Tit (200us)signal:If no collision has been detected,
LISTEN command:Device waiting until Tit=“0” then device start to read data in.
TALK command:Device send two bytes data after Tit.
4. Stop bit(“0”).
5. Start bit(“1”).
6. Service Request:When the device has data to report with SRQ=1,it will pull the ADB bus to be low for 300us
after first stop bit of the command send by Host.
COLLISION:
1. Host send one command,but many devices respond to it.
2. Losing device:
a. Device detects “0” at Tit-time before device wants to send start bit.
b. Data line must hold “1” at Tit-time,but device detects “0” by another device send.
c. Device detects“0”while sending“1”.
3. Losing device must give up ADB bus and data is saved.
4. Every devices must have detecting collision ability.
DYNAMIC SAMPLING RATE
When the mouse is moved,the frequence of sampling rate depends on the mouse’s speed.If the mouse is still,the
sampling rate is at low speed(1KHz).It can reduce system power consumption.
DPI
DOTS
SPEED(cm/sec) SAMPLING RATE
0
---------
1KHz
1
2.54
2.5KHz
200
2
5.08
5KHz
4
10.16
10KHz
0
---------
1KHz
1
1.5875
2.5KHz
320
2
3.175
5KHz
4
6.35
10KHz
0
---------
1KHz
1
1.27
2.5KHz
400
2
2.54
5KHz
4
5.08
10KHz
0
---------
1KHz
1
0.907
2.5KHz
560
2
1.814
5KHz
4
3.632
10KHz
Formula:speed=[ ( dots / DPI ) * 2.54 ) ] / Tb.
EX:dot=1,DPI=200 dots/inch,Tb(Time Base)=5ms
speed=[ ( 1 / 200 ) * 2.54 ] / 5ms=2.54 cm/sec
* This specification are subject to be changed without notice.
11.6.1995 5