DM9095 Ver la hoja de datos (PDF) - Davicom Semiconductor, Inc.
Número de pieza
componentes Descripción
Lista de partido
DM9095 Datasheet PDF : 21 Pages
| |||
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.
DM9095
Twisted-Pair Medium Attachment Unit
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.
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 a 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
Mode MD0
0
0
1
0
2
0
3
0
4
1
5
1
6
1
7
1
MD1
0
0
1
1
0
0
1
1
MD2
0
1
0
1
0
1
0
1
Heartbeat
No
No
No
Yes
Yes
Yes
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 TP 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
Line Length LI-
Application
Extended
I
Long wire TP
Normal
I
Normal wire TP
Normal
O LI pin LED output
Poer-down mode
Extended
I
Long wire TP
Normal
I
Normal wire TP
Normal
O LI pin LED output
Power-down mode
11
Final
Version: DM9095-DS-F02
August 21, 2000
Share Link: 