Pin Assignment

Pin Description

Pin No. Pin Name I/O

Description

USB Interface (2 pins)

3

USBD+

I/O USB data plus

4

USBD-

I/O USB data minus

General purpose I/O (9 pins)

6, 7

X1, X2

I

X-axis photo input with built-in Holtek's special dynamic photo in-

put resistor

8, 9

Y1, Y2

I

Y-axis photo input with built-in Holtek's special dynamic photo in-

put resistor

10, 11

Z1, Z2

I

Z-axis input supports two kinds of scroller input; optomechanical

and mechanical

12, 13,

14

L, R, M

I

These pins are input port with pull-high resistor. These pads can

function as Left, Right and Middle button input lines.

Miscellaneous (7 pins)

1

VSS

¾ Negative power supply, ground

2

V33O

O 3.3V voltage output

5

RESET

I

Chip reset input, low active

15

LED

I/O Drives LED output

16

VDD

¾ 5V positive power supply

17

OSC2

O 6MHz OSC output

18

OSC1

I

6MHz OSC input

HT82M91A

2

January 28, 2000

HT 8 2 M 9 1 A

1 8 D I P

18

17

16

15

14

13

12

11

10

1

2

3

4

5

6

7

8

9

VS S

V 33O

US B D +

US B D -

RE S E T

X1

X2

Y1

Y2

OS C 1

OS C 2

VD D

LE D

M

R

L

Z2

Z1