IDT77V1253L25PGI IDT, Integrated Device Technology Inc, IDT77V1253L25PGI Datasheet - Page 28

• Manufacturer Part Number: IDT77V1253L25PGI
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT77V1253L25PGI

• Data Rate: 25.6/51.2Mbps
• Number Of Channels: 3
• Type Of Atm Phy Interface: DPI/UTOPIA
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Pin Count: 144
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

TRIPLE PORT PHY (PHYSICAL LAYER) FOR 25.6
AND 51.2 MBPS ATM NETWORKS
DIAGNOSTIC FUNCTIONS
1. LOOPBACK
mode is controlled via bits 1 and 0 of the Diagnostic Control Registers:
Normal Mode
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".
There are two loopback modes supported by the 77V1253. The loopback
This mode, Figure 32, supports normal operating conditions: data to be
ATM Layer
ATM Layer
Device
Device
Bit 1
0
1
1
Utopia/DPI
Interface
Utopia/DPI
Interface
Bit 0
0
0
1
Normal operating mode
PHY Loopback
Line Loopback
TC sublayer
MODE
TC sublayer
Figure 33. PHY Loopback
Figure 32. Normal Mode
4781 tbl 12
28
PHY Loopback
within the PHY from the transmit PHY-ATM interface to the PHY-ATM receive
interface. Note that while this mode is operating, no data is forwarded to or
received from the line interface.
Line Loopback
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.
As Figure 33 illustrates below, this loopback mode provides a connection
Figure 34 might also be called “remote loopback” since it provides for a
PMD sublayer
PMD sublayer
4781 drw 34
4781 drw 33
Interface
Interface
Line
Line
IDT77V1253