IDT77V1254L25PGI IDT, Integrated Device Technology Inc, IDT77V1254L25PGI Datasheet - Page 28

• Manufacturer Part Number: IDT77V1254L25PGI
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT77V1254L25PGI

• Data Rate: 25.6/51.2Mbps
• Number Of Channels: 4
• 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

diagnostic aids. Refer to the Status and Control Register List section.
the respective port. The Interrupt Mask Registers allow individual masking of different interrupt sources. Additional interrupt signal control is provided
by bit 5 of the Master Control Registers. When this bit is set (=1), receive cell errors will be flagged via interrupt signalling and all other interrupt condi-
tions are masked. These errors include:
when an interrupt condition is detected. The external system should then interrogate the 77V1254L25 to determine which one (or more) conditions
caused this flag, and reset the interrupt for further occurrences. This is accomplished by reading the Interrupt Status Registers. Decoding the bits in
these bytes will tell which error condition caused the interrupt. Reading these registers also:
different colors to provide simple status indication at a glance. (The minimum value for R should be 330 ).
Diagnostic Function
IDT77V1254L25
!
!
The IDT77V1254L25 provides a variety of selectable interrupt and signalling conditions which are useful both during ‘normal’ operation, and as
Overall interrupt control is provided via bit 0 of the Master Control Registers. When this bit is cleared (set to 0), interrupt signalling is prevented on
Normal interrupt operations are performed by setting bit 0 and clearing bit 5 in the Master Control Registers. INT (pin 85) will go to a low state
This leaves the interrupt system ready to signal an alarm for further problems.
LED Control and Signaling
The LED outputs provide bi-directional LED drive capability of 8 mA. As an example, the RXLED outputs are described in the truth table:
As illustrated in the following drawing (Figure 31), this could be connected to provide for a two-LED condition indicator. These could also be
!
!
!
clears the (sticky) interrupt status bits in the registers that are read
resets INT
Bad receive HEC
Short (fewer than 53 bytes) cells
Received cell symbol error
RxLED(3:0)
TxLED(3:0)
Cells being received
Cells not being received
Cells being transmitted
Cells not being transmitted High
State
State
Figure 31 LED Indicator
TXLED Truth Table
R
R
28 of 48
3.3V
Low
High
Low
not being received or
Pin Voltage
Pin Voltage
(Indicates: Cells are
being received or
(Indicates: Cells
transmitted)
transmitted)
3505 drw 32
December 2004