IDT72P51777L7-5BBI IDT, Integrated Device Technology Inc, IDT72P51777L7-5BBI Datasheet - Page 44

• Manufacturer Part Number: IDT72P51777L7-5BBI
• Description: IC FLOW CTRL 40BIT 376-BGA
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT72P51777L7-5BBI

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 72P51777L7-5BBI

SWITCHING QUEUES ON THE READ PORT
configured up to a maximum of 128 queues. Data is read from a queue using
the Data Output (Qout) bus, Read Clock (RCLK) and Read Enable (REN)
signals. Selecting a queue on the read port occurs by placing the queue address
on the Read Address bus (RDADD) during a rising edge of RCLK while Read
changing (switching) queues every four (4) clock cycles. To switch from the
Present Queue (PQ) to another queue requires a queue address to be placed
on the Read Address Bus (RDADD) bus and a rising edge of Read Clock
(RCLK) and Read Address Enable (RADEN) is HIGH. There are no
restrictions as to the order to which queues are selected or switched into or out
of.
NOTE:
PQ = Present Queue
NQ = Next Queue
IDT72P51767/72P51777 1.8V, MULTI-QUEUE FLOW-CONTROL DEVICES
(128 QUEUES) 40 BIT WIDE CONFIGURATION 5,898,240 and 11,796,480 bits
The IDT72P51767/72P51777 multi-queue flow-control devices can be
The IDT72P51767/72P51777 multi-queue flow-control device supports
RADEN
RCLK
Qout
REN
RDADD
RADEN
RCLK
PQ
Queue
address
Figure 21. Read Port Switching Queues Signal Sequence
PQ
QS-1
Queue Switch Cycles
Figure 22. Switching Queues Bus Efficiency
Queue Switch Cycle
QS0
PQ
QS1
PQ
44
Address Enable (RADEN) is HIGH. For reference, the state of Read Enable
(REN) is a “Don’t Care” during a read port queue selection. REN has
significance during the queue mark operation. Selecting a queue requires 4
RCLK cycles. Refer to Figure 21, Read Port Switching Queues Signal
Sequence.
the IDT72P51767/72P51777 multi-queue flow-control device can continue to
read from the Present Queue (PQ). The Present Queue is defined as the current
selected queue. Refer to Figure 22. Switching Queues Bus Efficiency.
For maximum efficiency, during the 4 clock cycles required to switch queues
QS2
PQ
Queue
address
QS3
PQ
NQ
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
FEBRUARY 11, 2009
6724 drw16
6724 drw17