IDT77105L25TF IDT, Integrated Device Technology Inc, IDT77105L25TF Datasheet - Page 12

• Manufacturer Part Number: IDT77105L25TF
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT77105L25TF

• Data Rate: 25.6Mbps
• Number Of Channels: 1
• Type Of Atm Phy Interface: UTOPIA
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Pin Count: 64
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

problems.
Cable Disconnect Procedures and Link
Cable Disconnect Procedures and Link
Cable Disconnect Procedures and Link
Cable Disconnect Procedures and Link
Establishment
Establishment
Establishment
Establishment
some interrupts (“HEC Error Cell Received” interrupt, “Short Cell
Received” interrupt, and “Received Cell Symbol Error” interrupt) that
may appear. These interrupts should be masked.
this depends on the passive network between the magnetics and the
77105. Previous network recommendations did not adequately address
this matter, the result being that the receiver would generate needless
repetitive interrupts. The latest network recommendations, shown in
Figure 21, pull the RXD+ and RXD- inputs to different D.C. voltages in
the absence of a signal. This prevents false receive signals when there
is no actual signal, and thus prevent repetitive interrupts.
Register Status for Established Link
Register Status for Established Link
Register Status for Established Link
Register Status for Established Link
condition exists.
LED Control and Signalling
LED Control and Signalling
LED Control and Signalling
LED Control and Signalling
capability of 10mA. As an example, the RxLED pin’s output is described
in the truth table:
connected to provide for a two-LED condition indicator. These could also
be different colors to provide simple status indication at a glance. (The
value of R is determined to limit LED current to 10mA or less as speci-
fied by the LED manufacturer. Minimum value for R should be 270 ).
TxLED Truth Table (Pin 14)
TxLED Truth Table (Pin 14)
TxLED Truth Table (Pin 14)
TxLED Truth Table (Pin 14)
IDT77105
This leaves the interrupt system ready to signal an alarm for further
During the initial state of connecting the line for IDT77105, there are
When the line is disconnected, these interrupts may also appear, but
IDT77105 register setting and status are as follows when the link
The LED outputs, pins 13 and 14 provide bi-directional LED drive
As illustrated in the following drawing (Figure 8), this could be
Master Control Register 0x00
Interrupt Status Register 0x01
Diagnostic Control Register 0x02
Cell being received
Cells not being received
Cell being transmitted
Cells not being transmitted
State
State
Low
High
Low
High
Pin Voltage
Pin Voltage
contents => 49h
contents => 40h
contents => 00h
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Diagnostic Functions
Diagnostic Functions
Diagnostic Functions
Diagnostic Functions
1. Loopback
1. Loopback
1. Loopback
1. Loopback
back mode is controlled via Register 0x02, bits 1 and 0:
be transmitted is transferred to the TC, where it is queued and formatted
for transmission by the PMD. Receive data from the PMD is decoded
along with its clock for transfer to the receiving "upstream system".
connection within the PHY between transmit and receive data. Note that
while this mode is operating, no data is forwarded to or received from
the line interface.
a means to test the overall system, including the line. Since this mode
will probably be entered under direction from another system (at a
remote location), receive data is also decoded and transferred to the
upstream system to allow it to listen for commands. A common example
would be a command asking the upstream system to direct the TC to
leave this loopback state, and resume normal operations.
after receiving a complete cell, the cell is transmitted.
There are two loopback modes supported by the 77105. The loop-
Normal Mode
This mode, Figure 9, supports normal operating conditions: data to
PHY Loopback
As Figure 10 illustrates below, this loopback mode provides a
Line Loopback
Figure 11 might also be called “remote loopback” since it provides for
Entering Loopback (Byte Mode)
In byte mode, the 77105 counts 53 bytes after each TxSOC, and
0x02
RxLED,
Pin 13
Bit 1
0
1
1
Bit 0
R
R
0
0
1
Figure 8
Vcc
Normal operating mode
PHY Loopback
Line Loopback
(Indicates: Cells are
not being received)
September 11, 2000
(Indicates: Cells
being received)
3445 drw 11