Silan

Semiconductors

SC83702

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0

2000.12.31

6

FUNCTION DESCRIPTIONS

1.OPERATING MODE

A) Mouse System Mode

Anytime the mouse changes its state, including the key-switches and the photo-couple sensors, SC83702 will

detect the result and transmit to RS-232C. Mouse system transmits the result with five bytes in 1200 baud rate.

Each byte contains 10 bits, one start bit, one stop bit and eight data bits. The first byte represents the key-

switches status. The second byte denotes the number counted by the horizontal counter. The third byte conveys

the number accumulated by the vertical counter. If the mouse is moved faster, the photo-couple sensors detect

the "change state" and output the record, excessive horizontal counter will be transported through the fourth byte

and vertical counter through the fifth byte. Otherwise, the fourth and fifth byte are zero. Output bytes arrange:

Bit No.

765

432

1

0

1st Byte

100

00

L’*

M’*

R’*

2nd Byte

H7

H6

H5

H4

H3

H2

H1

H0

3rd Byte

V7

V6

V5

V4

V3

V2

V1

V0

4th Byte

H7

H6

H5

H4

H3

H2

H1

H0

5th Byte

V7

V6

V5

V4

V3

V2

V1

V0

B) Microsoft Mode

In microsoft mode, the transmission cycle consists of three bytes. Each byte is divided into one start bit, seven

data bits and two stop bits. The first byte contains "L", "R" switch status and four bits of the two most significant

bits in horizontal counter and vertical counter. The next byte represents the value accumulated by horizontal

counter, the last byte is the data of the vertical counter. Notice that "M" key-switch is not active in the microsoft

mode and the vertical data is transmitted in 2's complement.

Bit No.

6

543

21

0

1st Byte

1L

R

V7'

V6'

H7

H6

2nd Byte

0

H5H4H3

H2H1

H0

3rd Byte

0

V5'

V4'

V3'

V2'

V1'

V0'

2.TESTING MODE

generators will present to L and M pin. Pressing "R" key can toggle the output from X direction to "Y" direction.

3.ECHO MODE

RXD will send out CD (H) code when RTS rise from low to high under microsoft mode. Under mouse system

mode, when RTS rise from low to high, the RXD pin SC83702 will send out two byte C8 (H) code.