4

AV9155

Pin Configuration

Pin Descriptions for AV9155-23, -36

20-Pin DIP or SOIC

20-Pin DIP or SOIC

PIN

NUMBER

PIN

NAME

TYPE

DESCRIPTION

1

1.843/40 MHz

Output

1.84 MHz (-23)/40 MHz SCSI (-36) clock output.

2

X2

Output

Crystal connection.

3

X1

Input

Crystal connection.

4

VDD

-

Digital power supply (+5V)

5

GND

-

Digital ground.

6

16 MHz/15 MHz

Output

16 MHz (-23)/15 MHz (-36) clock output.

7

24 MHz

Output

24 MHz floppy disk/combination I/O clock output.

8

12 MHz

Output

12 MHz keyboard clock output.

9

AGND

-

Analog ground (original version).

10

OE

Input

Output enable. Tristates all outputs when low. (Has internal pull-up.)

11

FS2

Input

CPU clock frequency select #2. (-23 has internal pull-up.)

12

PD#

Input

Power-down. Shuts off entire chip when low. (Has internal pull-up.)

13

14.318 MHz

Output

14.318 MHz reference clock output.

14

14.318 MHz

Output

14.318 MHz reference clock output.

15

GND

-

Digital ground.

16

VDD

-

Digital power supply (3.3V or 5.0V).

17

2XCPU

Output

2X CPU clock output.

18

CPU

Output

1X CPU clock output.

19

FS1

Input

CPU clock frequency select #1. (-23 has internal pull-up.)

20

FS0

Input

CPU clock frequency select #0. (-23 has internal pull-up.)