IDT72V51246L7-5BB IDT, Integrated Device Technology Inc, IDT72V51246L7-5BB Datasheet - Page 23

• Manufacturer Part Number: IDT72V51246L7-5BB
• Description: IC FLOW CTRL MULTI QUEUE 256-BGA
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT72V51246L7-5BB

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 72V51246L7-5BB

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.
OUTPUT VALID FLAG OPERATION
output, OV. The OV provides an empty status or data output valid status for the
data word currently available on the output register of the read port. The rising
edge of an RCLK cycle that places new data onto the output register of the read
port, also updates the OV flag to show whether or not that new data word is
actually valid. Internally the multi-queue flow-control monitors and maintains a
status of the empty condition of all queues within it, however only the queue that
is selected for read operations has its output valid (empty) status output to the
OV flag, giving a valid status for the word being read at that time.
IDT72V51236/72V51246/72V51256 3.3V, MULTI-QUEUE FLOW-CONTROL DEVICES
(4 QUEUES) 36 BIT WIDE CONFIGURATION 589,824, 1,179,648 and 2,359,296 bits
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
The multi-queue flow-control device provides a single Output Valid flag
23
data word is read from a selected queue, the OV flag will go HIGH on the next
enabled read, that is, on the next rising edge of RCLK while REN is LOW.
to show status of the new queue in line with the data output from the new queue.
When a queue selection is made the first data from that queue will appear on
the Qout data outputs 2 RCLK cycles later, the OV will change state to indicate
validity of the data from the newly selected queue on this 2
The previous cycles will continue to output data from the previous queue and
the OV flag will indicate the status of those outputs. Again, the OV flag always
indicates status for the data currently present on the output register.
based on a rising edge of RCLK. Internally the multi-queue device monitors and
keeps a record of the output valid (empty) status for all queues. It is possible that
the status of an OV flag may be changing internally even though that respective
flag is not the active queue flag (selected on the read port). A queue selected
on the write port may experience a change of its internal OV flag status based
on write operations, that is, data may be written into that queue causing it to
become “not empty”.
Valid Flag Timing for details of the timing.
EXPANSION MODE – OUTPUT VALID FLAG OPERATION
of all devices should be connected together, such that a system controller
monitoring and managing the multi-queue devices read port only looks at a
single OV flag (as opposed to a discrete OV flag for each device). This OV flag
is only pertinent to the queue being selected for read operations at that time.
Remember, that when in expansion mode only one multi-queue device can be
read from at any moment in time, thus the OV flag provides status of the active
queue on the read port.
output have a High-Impedance capability, such that when a queue selection is
made only a single device drives the OV flag bus and all other OV flag outputs
connected to the OV 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 OV flag output into High-Impedance when
none of its queues are selected for read operations.
flag output of that device will maintain control of the OV flag bus. Its OV flag will
simply update between queue switches to show the respective queue output
valid status.
on the 3 bit ID code found in the 3 most significant bits of the read queue address
bus, RDADD. If the 3 most significant bits of RDADD match the 3 bit ID code setup
on the static inputs, ID0, ID1 and ID2 then the OV flag output of the respective
device will be in a Low-Impedance state. If they do not match, then the OV flag
output of the respective device will be in a High-Impedance state. See Figure
13, Output Valid Flag Timing for details of flag operation, including when more
than one device is connected in expansion.
ALMOST FULL FLAG
single Programmable Almost Full flag output, PAF. The PAF flag output provides
a status of the almost full condition for the active queue currently selected on the
write port for write operations. Internally the multi-queue flow-control device
monitors and maintains a status of the almost full condition of all queues within
it, however only the queue that is selected for write operations has its full status
The nature of the first word fall through operation means that when the last
When queue switches are being made on the read port, the OV flag will switch
The OV flag is synchronous to the RCLK and all transitions of the OV flag occur
See Figure 12, Read Queue Select, Read Operation and Figure 13, Output
When multi-queue devices are connected in Expansion mode, the OV flags
This connection of flag outputs to create a single flag requires that the OV flag
When queues within a single device are selected for read operations, the OV
The multi-queue device places its OV flag output into High-Impedance based
As previously mentioned the multi-queue flow-control device provides a
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
nd
RCLK cycle also.