IDT72V51353L7-5BB8 IDT, Integrated Device Technology Inc, IDT72V51353L7-5BB8 Datasheet - Page 18

• Manufacturer Part Number: IDT72V51353L7-5BB8
• Description: IC FLOW CTRL MULTI QUEUE 256-BGA
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT72V51353L7-5BB8

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 72V51353L7-5BB8

NULL QUEUE OPERATION (OF THE READ PORT)
utilization in standard mode. Data can be read out of the multi-queue flow-control
device on every RCLK cycle regardless of queue switches or other opera-
tions. The device architecture is such that the pipeline is constantly filled with
the next words in a selected queue to be read out, again providing 100% bus
utilization. This type of architecture does assume that the user is constantly
switching queues such that during a queue switch, the last data word required
from the previous queue will fall through the pipeline to the output.
will automatically flow through the pipeline to the output.
RDADD[6:0] bus should be addressed with xxx1xxx, this address is the Null-Q.
A null queue can be selected when no further reads are required from a
previously selected queue. Changing to a null queue will continue to propagate
data in the pipeline to the previous queue’s output. The Null-Q can remain
selected until a data becomes available in another queue for reading. The Null-Q
can be utilized in either standard or packet mode.
as and treated as an empty queue, therefore after switching to the null queue
the last word from the previous queue will remain in the output register and the
OV flag will go HIGH, indicating data is not valid.
queue, it is a means to force data through the pipeline to the output. Null-Q
selection and operation has no meaning on the write port of the device. Also,
refer to Figure 16, Read Operation and Null Queue Select for diagram.
BUS MATCHING OPERATION
During a master reset of the multi-queue the state of the two setup pins, IW (Input
Width) and OW (Output Width) determine the input and output port bus widths
as per the selections shown in Table 3, “Bus Matching Set-up”. 9 bit bytes or
18 bit words can be written into and read from the queues. When writing to or
reading from the multi-queue in a bus matching mode, the device orders data
in a “Little Endian” format. See Figure 3, Bus Matching Byte Arrangement for
details.
reads of data widths determined by the write port width. For example, if the input
port is x18 and the output port is x9, then two data reads from a full queue will
be required to cause the full flag to go HIGH (queue not full). Conversely, the
Output Valid flag and Almost Empty flag operations are always based on writes
and reads of data widths determined by the read port. For example, if the input
port is x9 and the output port is x18, two write operations will be required to cause
the output valid flag of an empty queue to go LOW, output valid (queue is not
empty).
port, therefore the input bus width to all queues is equal (determined by the input
port size) and the output bus width from all queues is equal (determined by the
output port size).
TABLE 3 — BUS-MATCHING SET-UP
IDT72V51333/72V51343/72V51353 3.3V, MULTI-QUEUE FLOW-CONTROL DEVICES
(8 QUEUES) 18 BIT WIDE CONFIGURATION 589,824, 1,179,648 and 2,359,296 bits
Pipelining of data to the output port enables the device to provide 100% bus
Note, that if reads cease at the empty boundary of a queue, then the last word
The Null-Q is selected via read port address space RDADD[3]. The
Note: If the user switches the read port to the null queue, this queue is seen
The Null queue operation only has significance to the read port of the multi-
Bus Matching operation between the input port and output port is available.
The Full flag and Almost Full flag operation is always based on writes and
Note, that the input port serves all queues within a device, as does the output
I W
0
0
1
1
OW
0
1
0
1
Write Port
x18
x18
x9
x9
Read Port
x18
x18
x9
x9
18
FULL FLAG OPERATION
The FF flag output provides a full status of the queue currently selected on the
write port for write operations. Internally the multi-queue flow-control device
monitors and maintains a status of the full condition of all queues within it, however
only the queue that is selected for write operations has its full status output to the
FF flag. This dedicated flag is often referred to as the “active queue full flag”.
will switch to the new queue and provide the user with the new queue status,
on the cycle after a new queue selection is made. The user then has a full status
for the new queue one cycle ahead of the WCLK rising edge that data can be
written into the new queue. That is, a new queue can be selected on the write
port via the WRADD bus, WADEN enable and a rising edge of WCLK. On the
next rising edge of WCLK, the FF flag output will show the full status of the newly
selected queue. On the second rising edge of WCLK following the queue
selection, data can be written into the newly selected queue provided that data
and enable setup & hold times are met.
cycle after queue selection, which is one cycle before data can be written to that
queue. This prevents the user from writing data to a queue that is full, (assuming
that a queue switch has been made to a queue that is actually full).
based on a rising edge of WCLK. Internally the multi-queue device monitors and
keeps a record of the full status for all queues. It is possible that the status of a
FF flag maybe changing internally even though that flag is not the active queue
flag (selected on the write port). A queue selected on the read port may
experience a change of its internal full flag status based on read operations.
and Figure 11, Full Flag Timing in Expansion Mode for timing information.
EXPANSION MODE - FULL FLAG OPERATION
of all devices should be connected together, such that a system controller
monitoring and managing the multi-queue devices write port only looks at a
single FF flag (as opposed to a discrete FF flag for each device). This FF flag
is only pertinent to the queue being selected for write operations at that time.
Remember, that when in expansion mode only one multi-queue device can be
written to at any moment in time, thus the FF flag provides status of the active
queue on the write port.
output have a High-Impedance capability, such that when a queue selection is
made only a single device drives the FF flag bus and all other FF flag outputs
connected to the FF flag bus are placed into High-Impedance. The user does
not have to select this High-Impedance state, a given multi-queue flow-control
device will automatically place its FF flag output into High-Impedance when none
of its queues are selected for write operations.
flag output of that device will maintain control of the FF flag bus. Its FF flag will
simply update between queue switches to show the respective queue full status.
on the 3 bit ID code found in the 3 most significant bits of the write queue address
bus, WRADD. If the 3 most significant bits of WRADD match the 3 bit ID code setup
on the static inputs, ID0, ID1 and ID2 then the FF flag output of the respective
device will be in a Low-Impedance state. If they do not match, then the FF flag
output of the respective device will be in a High-Impedance state. See Figure
11, Full Flag Timing in Expansion Mode for details of flag operation, including
when more than one device is connected in expansion.
The multi-queue flow-control device provides a single Full Flag output, FF.
When queue switches are being made on the write port, the FF flag output
Note, the FF flag will provide status of a newly selected queue one WCLK
The FF flag is synchronous to the WCLK and all transitions of the FF flag occur
See Figure 9, Write Queue Select, Write Operation and Full Flag Operation
When multi-queue devices are connected in Expansion mode the FF flags
This connection of flag outputs to create a single flag requires that the FF flag
When queues within a single device are selected for write operations, the FF
The multi-queue device places its FF flag output into High-Impedance based
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES