IDT72P51759L6BBI8 IDT, Integrated Device Technology Inc, IDT72P51759L6BBI8 Datasheet - Page 29

• Manufacturer Part Number: IDT72P51759L6BBI8
• Description: IC FLOW CTRL 36BIT 256-BGA
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT72P51759L6BBI8

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 72P51759L6BBI8

SWITCHING QUEUES ON THE WRITE PORT
can be configured up to a maximum of 128 queues. Data is written into a queue
using the Data Input (Din) bus, Write Clock (WCLK) and Write Enable (WEN)
signals. Selecting a queue occurs by placing the queue address on the Write
supports 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 Write Address Bus (WRADD) bus and a rising edge of Write
Clock (WCLK) and Write Address Enable (WADEN) is HIGH. There are no
restrictions as to the order to which queues are selected or switched into or out
of.
NOTES:
1. PQ = Present Queue
* Requires 4 clock cycles to switch queues.
IDT72P51749/72P51759/72P51769 1.8V, MULTI-QUEUE FLOW-CONTROL DEVICES
(128 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648, 2,359,296, and 4,718,592
bits
The IDT72P51749/72P51759/72P51769 multi-queue flow-control devices
The IDT72P51749/72P51759/72P51769 multi-queue flow-control device
NQ = Next Queue
WADEN
WCLK
WEN
Din
WRADD
WADEN
WCLK
PQ
Queue
address
Figure 7. Write Port Switching Queues Signal Sequence
Queue Switch Cycles *
QS-1
PQ
Figure 8. Switching Queues Bus Efficiency
Queue Switch Cycle
QS0
PQ
QS1
PQ
29
Address bus (WRADD) during a rising edge of WCLK while Write Address
Enable (WADEN) is HIGH. For reference, the state of Write Enable (WEN) is
a “Don’t Care” during a queue selection. WEN has significance during the queue
mark operation. Selecting a queue requires 4 WCLK cycles. Refer to Figure
7, Write Port Switching Queues Signal Sequence.
the IDT72P51749/72P51759/72P51769 multi-queue flow-control device can
continue to write into the Present Queue (PQ). The Present Queue is defined
as the current selected queue. Refer to Figure 8, Switching Queues Bus
Efficiency.
QS2
For maximum efficiency, during the 4 clock cycles required to switch queues
NQ
Queue
address
QS3
NQ
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
6714 drw13
FEBRUARY 10, 2009
6714 drw14