DS-0021 Jun 05

Page 7

OX12PCI840

OXFORD SEMICONDUCTOR LTD.

Pin Numbers

Name

Description

Multi-purpose & External interrupt pins

82, 51

I/O

MIO[1:0]

Multi-purpose I/O pins. Can drive high or low, or assert a PCI

interrupt

EEPROM pins

81

O

EE_CK

EEPROM clock

78

O

EE_CS

EEPROM active-high Chip Select

80

IU

EE_DI

EEPROM data in. When the serial EEPROM is connected,

this pin should be pulled up using 1-10k resistor. When the

EEPROM is not used the internal pull-up is sufficient.

79

O

EE_DO

EEPROM data out.

Miscellaneous pins

77

I

TEST

Test Pin : should be held low at all times

8,30,40,56,97

V

AC VDD

Supplies power to output buffers in switching (AC) state

16,45,67,87

V

DC VDD

Power supply. Supplies power to core logic, input buffers

and output buffers in steady state

3,7,20,29,35,41,48,55,61,72,92,96

G

AC GND

Supplies GND to output buffers in switching (AC) state

15,44,66,85

G

DC GND

Ground (0 volts). Supplies GND to core logic, input buffers

and output buffers in steady state

Table 1: Pin Descriptions

Note 1: Direction key:

I

Input

ID

Input with internal pull-down

O

Output

I/O

Bi-directional

OD

Open drain

NC

No connect

Z

High impedance

P_I

PCI input

P_O

PCI output

P_I/O

PCI bi-directional

P_OD

PCI open drain

G

Ground

V

5.0V power

Note 2: Power & Ground

There are two GND and two VDD rails internally. One set of rails supply power and ground to output buffers while in switching

state (called AC power) and another rail supply the core logic, input buffers and output buffers in steady-state (called DC rail).

The rails are not connected internally. This precaution reduces the effects of simultaneous switching outputs and undesirable RF

radiation from the chip. Further precaution is taken by segmenting the GND and VDD AC rails to isolate the PCI and Local Bus

pins.