COM90C66 datasheet(6/76 Pages) SMSC

6 / 76 page

DESCRIPTION OF PIN FUNCTIONS

PLCC

PIN NO.

NAME

SYMBOL

DESCRIPTION

nI/O 16-Bit

Chip Select

nIOCS16

Output. This active low signal is used to indicate that the

present data transfer is a 16-bit I/O cycle. A15-A2 are

used to generate nIOCS16. This is an open-drain signal.

An external pull-up resistor is typically provided by the

system.

nSystem Bus

High Enable

nSBHE

Input.

This active low signal is used to enable the

COM90C66 to transfer data on D8-D15 of the Data Bus.

TRANSMISSION MEDIA INTERFACE

56, 55

nPulse 2,

nPulse 1

nPULSE 2,

nPULSE 1

Output. These active low signals carry the transmit data

information,

encoded

pulse

format,

from

the

COM90C66 to the LAN Driver.

Receive In

RXIN

Input.

This signal carries the receive data information

from the LAN Driver to the COM90C66.

MISCELLANEOUS

51-47

Memory Base

Address Select

MS0-MS4

Input. These signals are generated by external switches.

They are used by the memory decoder to select a block

of memory.

These signals are connected to weak

internal pull-up resistors.

46-44

I/O Base

Address Select

IOS0-IOS2

Input. These signals are generated by external switches.

They are used by the I/O decoder to select a block of 16

I/O locations.

These signals are connected to weak

internal pull-up resistors.

35-42

Node ID Select

NID0-NID7

Input. These signals are generated by external switches.

The Node ID code represents the node identification of

this particular COM90C66. These signals are connected

to weak internal pull-up resistors.

nTransmit

Activity LED

nTXLED

Output.

This active low signal is used for direct

connection to an LED through a resistor to Vcc to indicate

transmit activity. This signal has 12mA sink capability.

nBoard Select

Activity LED

nnBSLED

Output.

This active low signal is used for direct

connection to an LED through a resistor to Vcc to indicate

board activity. This signal has 12mA sink capability.

COM90C66 Datasheet(PDF) 6 Page - SMSC Corporation

COM90C66 Datasheet(HTML) 6 Page - SMSC Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76

Datasheet Download

Link URL