DM9095 datasheet(11/21 Pages) ETC

11 / 21 page

DM9095

Twisted-Pair Medium Attachment Unit

Final

Version: DM9095-DS-F02

August 21, 2000

Crystal Oscillator

An external TTL-Level clock can be applied to the

OSC1 pin which is crystal oscillator input.

A resistor

should be added in series with the clock source to limit

the amplitude of the voltage swing seen by the pin.

A 500

resistor works well in most cases.

LED Status Functions

The LED drivers require an external resistor in series

with the LED, which is in turn connected to VDD.

The driver pulls the pin low to light the LED and can

sink up to 15mA of drive current from the resistor with

an output impedance of less than 50

The

DM9095 provides three types LED drivers, as follows.

Output LED Drivers: The LED outputs XLED, RLED,

JLED, and CLED are output LED drivers.

These

signals are used for status information only.

XLED

drives high when the DM9095 is transmitting a packet.

XLED is not asserted if the DM9095 has detected a

jabber function or is in a link-fail state. RLED drives

high when the DM9095 is receiving a packet.

RLED

is not asserted when the DM9095 is in a link-fail state.

JLED drives low when the DM9095 has detected a

jabber condition.

CLED drives low when the

DM9095

has

detected

collision

condition.

Sampled LED Driver: The AP pin is used to set the

configuration of the DM9095 and drive the LED status

indicators.

Every 26ms, the pin is configured as an

input pin for 6.5• s.

During this time, it is sampled by

the DM9095.

Outside the sampling window, the

driver is placed in an output state and used to drive

the LED indicators.

AP is driven low to indicate that

a reversed twisted pair has been detected on the

receive circuit and corrected.

If AP is tied low,

DM9095 disables the auto-polarity function; when AP

is pulled high externally, the function is enabled.

Input / Output LED Driver: LI-pin is an input/output

pin, depending on the mode selection.

When

configured as an input pin, LI-controls the link integrity

test option.

If LI- is connected to GND, the link

integrity function is enabled.

If LI- is connected to

VDD or left floating (internal pull-high), the link

integrity function is disabled.

When configured as an

output pin, the pin drives low for link-fail state and

drives high for link-pass state.

The output pin can

drive an LED status indicator.

Power

There are six power connections to the DM9095,

including three VDD and three GND connections.

Pins 1 and 28 are used for analog supplies, including

squelch circuits, receiver, and the internal delay

circuit.

Pins 10 and 14 are used for digital circuits,

the I/O buffer, the control logic for analog circuits, and

the crystal oscillator circuit.

Pins 18 and 23 are used

for the Twisted Pair driver output buffer.

Operating Modes

The mode selection pins are used to select one of

eight

operating

modes.

These

modes

are

summarized in the table below.

The modes referred to in the table are the following:

z Heartbeat: A Yest means that the heartbeat

function is enabled; A No means the

heartbeat function is disabled.

z Line Length: “Extended” indicates that TP receive

squelch

thresholds

have

been

lowered to 300mV for use with longer

line lengths; Normal indicates that the

standard

10BASE-T

receive

squelch threshold of 450mV will be

used.

z LI-: The LI- pin can be configured to be an input

pin, whereby the link-integrity function can be

enabled or disabled.

The LI- pin can also be

configured as an output pin to indicate the

status of the link, where the link-integrity is

enabled.

Mode Description

Mode

MD0

MD1

MD2

Heartbeat

Line Length

LI-

Application

0000

Extended

Long wire TP

1001

Normal

Normal wire TP

2010

Normal

LI pin LED output

3011

Poer-down mode

4100

Yes

Extended

Long wire TP

5101

Yes

Normal

Normal wire TP

6110

Yes

Normal

LI pin LED output

7111

Power-down mode

DM9095 Datasheet(PDF) 11 Page - List of Unclassifed Manufacturers

DM9095 Datasheet(HTML) 11 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Datasheet Download

Link URL