Davicom DM9095L Datasheet
General Description
DM9095
Twisted-Pai r Medium Attachment Un it
The DM9095 twisted-pair Media Attachment Unit
(TPMAU) is designed to allow Ethernet connections
to use existing Twisted-pair wiring plants through an
Ethernet At tachment Unit Inter face (AUI). The
DM9095 provides the electrical interface between
the AUI and the twisted-pair wire.
The DM9095’s functions include level-shifted data
pass-through from one transmission media to
another, collision detection, transmitting predistortion
Block Diagram
DO +
DO -
AUI
Data
Receiver
Jabber
AUI
Data
Squelch
generation, receiving squelch function, selectable
signal-quality-error (SQE) test generation, a linkintegrity strapping option, and automatic correction
of polarity reversal on the twiste d pair input. The
DM9095 also includes LED drivers for transmit,
receive, jabber , collision, reversed polarity detect
and link status.
The DM9095 is an advanced CMOS device
available in 28-pin PLCC packages.
TP
Pre-Distortion
Driver
TPO +
DTPO +
DTPO TPO-
MD0
MD1
MD2
DI +
DI -
CI +
CI -
OSC1
Operation
Mode
Selection
AUI
Current
Driver
Collision
Current
Driver
Crystal
Oscillator
Loopback
Control
Collision
Control
LED
Drivers
RLED CLED XLED JLED
Link
Integrity
Auto-Polarity
Detection
TP
Data
Receiver
TP
Data
Squelch
LI-
AP
TPI +
TPI -
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Version: DM9095-DS-F02
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Features
DM9095
Twisted-Pai r Medium Attachment Un it
• Compatible with or exceeds IEEE 802.3
standards for AUI and 10BASE-T interfaces
• Internal pre-distortion generator for TP driver
• Smart squelch circuitry on all received data
• Selectable heartbeat function
• Selectable line-integrity test with LED indication
• LED indicator for tr ansmit, rec eiv e, jabber, and
collision
• Advanced analog CMOS process using single 5V
Pin Configuration : DM9095L
GND
1
VDD
28
TPI+
27
TPI-
26
25
24
23
LI-
DI+
DI-
5
6
7
MDO
4
DO-
3
DO+
2
supply
• Lower TP threshold option for long length
application
• Selectable auto-polarity detection and correction
function wit h LED indication
• Automatic AUI/RJ45 selection
• Power-down mode
• Full ESD protection
MD1
MD2
GND
CI+
CI-
VDD
AP
10
11
8
9
12
JLED
13
OSC1
DM9095L
14
15
GND
CLED
16
RLED
17
XLED
22
21
20
19
18
VDD
TPO-
DTPO-
DTPO+
TPO+
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Version: DM9095-DS-F02
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Twisted-Pai r Medium Attachment Un it
Pin Description
Pin No. Pin Name I/O Descriptio n
1 GND - Ground
DM9095
2
3
4 MD0 I Operation mode selection pin. Pulled high internally.
5 LI- Link-Integrity enable. The pin is a dual function pin that
6
7
8
9
DO+
DO-
DI+
DI-
CI+
CI-
I Transmitter input. A balanced differential line receiver input pair
from the AUI circuit that receives 10 Mbits/s Manchester-encoded
data and applies the data to the TP cable.
determines whether the link integrity function should be realized.
When this pin, which is internally pulled-high, is configured as an
input pin and tied low, the link integrity test function is enabled.
While 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, as in Figure 3(b) (page 6).
O Receiver outputs. A balanced output current driver pair to the AUI
transceiver cable with the 10 Mbits/s Manchester-encoded data
received from the twisted-pair of the network.
O Collision outputs. Balanced differenti al line driver outputs which
send a 10MHz oscillation signal to the Manchester
encoder/decoder in the event of a collision, jabber interrupt, or
heartbeat test.
10 VDD - +5V Power Supply
11 AP I/O Auto Polarity. This pin is a dual func tion pin which determines if
the auto-polarity function should be enabled. The function is
enabled if the pin is HIGH. The pin is also capable of driving an
LED if the function is enabled.
12 JLED O Jabber indicator. Normally off. It indicates a time-out
transmi ssion onto TP network . It turns on i f the watchdog timer
has timed out and the twisted-pair driver has been disabled.
13 OSC1 I Crystal pin. This pin is a 20MHz frequency-reference terminal for
internal chip timing.
14 GND - Ground
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Version: DM9095-DS-F02
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DM9095
Twisted-Pai r Medium Attachment Un it
Pin Descr iption (contin ued)
Pin No. Pin Name I/O Descriptio n
15 LCED O Collision indicator. Normally off. It indicates a collision has been
detected by the M AU. It turns on the LED if a collision occurs.
16 RLED O Receive Indicator. Normally on. It indicates a reception from the
TP network is in progress. When LI- is disabled, RLED will turn
off i f the MAU receives a packet. When LI- is enabled, RLED will
turn off as long as the link is broken.
17 XLED O Transmit indicator. Normally on. It indicates that a
transmiwwion onto the TP network is in progress by turning off.
18 VDD O +5V Power Supply
19
20
21
22
23 GND - Ground
24 MD2 I Operation mode selection pin. Pulled high internally
25 MD1 I Operation mode selection pin. Pulled high internally
26
27
28 VDD O + 5V Power Supply
TPO+
DTPO+
DTPO-
TPO-
TPI-
TPI+
O TP driver outputs. These four outputs provide the TP drivers with
pre-distortion capability. The TPO+ /TPO- outputs generate
10Mbits/s Manchester- enc oded data. The DTPO+ /DTPO-
outputs are one-half bit time delayed and inverted with respect to
TPO+ /TPO-.
I TP Receive input. A differential receiver tied to the receive
transformer pair of the twisted-pair wire. The receive pair of the
twisted-pair medium is driven with 10Mbits/s Manchester-encoded
data.
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Version: DM9095-DS-F02
August 21, 2000
Overview
DM9095
Twisted-Pai r Medium Attachment Un it
The DM9095 provi des the int erf ac e between an AUI and
a TP wire. The receive, tr ansmit, and c ollision detection
functi ons of t he DM9095 are designed t o m eet t he I EEE
802.3 10BASE-T draft standard. The receive section
transfers 10Mbits/s Manchester-encoded data from the
twisted-pair to the AUI, while the transmit section transfers
data from the AUI cable to the TP wire. The collisiondetection functi on sends a 10MHz square wav e ont o t he
AUI_CI circuits after sensing data being simultaneously
transmitted and received.
In addition to the these functions, there are three optional
operating functions. Enabling the link-integrity function
causes a pulse to be transmitted in t he absence of data
transmission. The Receiver recognized link-integrity
pulses and connects the twisted-pair link. The linkintegrity pin can be configured as an input or as an output.
When the l ink-i ntegrity pi n is confi gured as an input, the
function is enabled for proper setting. When the linkintegrity pin is configured as an output, the function is
enabled and the status of the link is indicated.
If the heartbeat function is enabled, it allows the SQE-test
sequence to be transmitted to the DTE after every
successful transmission on t he TP wi r e. The opt ion also
enables normal or ex tended line length to be selected.
When standard TP squelch levels are implemented,
normal line length is used. When the TP squelch
thresholds are lowered, extended line length is used.
The devi ce also contains an auto-polari ty func tion which
can be determined if the recei ve twisted-pair has been
wired with polarit y reversal. If the twisted-pair i s wired
with polarity reversal, the device automatically corr ec ts for
this error condit ion. Also, the auto-pol arity f unction c an
be used with an LED to display the polarity of the receive
twisted-pair wire.
When power-down m ode is set, the dev ice shuts down,
and the supply current is reduced to less than 10 µA. The
DM9095 automatically pulls AUI-DI, AUI_CI, and AUI-DO
into high impedance state if the twisted-pair link is not
connected. The function is used to provide the
Encoder/Decoder chip to use coaxial MAU. The
DM9095 also includes four drivers capable of driving four
LEDs to indicate the status of the receive, transmit,
collis io n , and jabber functions. Also, when configured
correctly, two additional LEDs can display auto-polarity
and link-integrity status.
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Version: DM9095-DS-F02
August 21, 2000
DM9095
Twisted-Pai r Medium Attachment Un it
Figure 3 (a). Typical System Application for External TPMAU in Mode 5
(Where Link I ntegr ity Test is enabled, A uto-polarity is
disabled. LI- is input pin)
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Version: DM9095-DS-F02
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D
M9095
DM9095
Twisted-Pai r Medium Attachment Un it
Figure 3 (b). Typical System Application for Internal TPMAU in Mode 6
(Where Lin k In tegrity Test is enabled and Auto Pola rity
Function is enabled. LI- is output pin)
7 Final
Version: DM9095-DS-F02
August 21, 2000
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