Primitive: Bi-Directional Single-ended Buffer with DCI
and Input Disable
This design element is a bidirectional
single ended I/O buffer used to connect internal logic to an external
bidirectional pin. This element includes Digitally Controlled Impedance
(DCI) termination enable/disable as well as input path disable as
additional power saving features when the I/O is either in an unused
state or being used as an output for a sustained amount of time. This
element may only be placed in High Performance (HP) banks in the 7 series devices.
||Bi-directional port connection. Connect directly to top-level
port in the design.
||Buffer input representing the output path to the device.
||Disables input path. When this signal is asserted HIGH and
the attribute USE_IBUFDISABLE is set to "TRUE", the input path through
the input buffer is disabled and forced to a logic HIGH. If USE_IBUFDISABLE
is set to "FALSE" this input is ignored and should be tied to ground.
This feature is generally used to reduce power at times when the
I/O is either idle or during sustained write (output) conditions.
||Disables DCI termination. When this signal is asserted HIGH,
DCI termination is disabled. This feature is generally used to reduce
power at times when the I/O is either idle or during sustained write
||Sets the I/O in a high impedance 3-state mode when the I/O
is being used for a read (input) operation. The T pin also affects
the IBUFDISABLE function when USE_IBUFDISABLE = "TRUE".
||Buffer output representing the input path to the device.
Design Entry Method
||2, 4, 6, 8, 12, 16, 24
||Selects output drive strength (mA) for the SelectIO™ buffers.
||Allows a trade off of lower power consumption vs. highest performance.
||See Data Sheet
||Assigns an I/O standard to the element.
||Sets the output rise and fall time. See the Data Sheet for
recommendations of the best setting for this attribute.
||Enables or disables the feature of IBUFDISABLE. Set to FALSE
when it is not desirable to have the T pin disable input path to allow
a read during write operation. When set to TRUE deasserting T (IO
used as output) or asserting IBUFDISABLE will disable the input path
through the buffer and forces to a logic high.
Unless they already exist, copy the following
two statements and paste them before the entity declaration.
-- IOBUF_DCIEN: Single-ended Bi-directional Buffer with Digital Controlled Impedance (DCI)
-- and Input path enable/disable
-- May only be placed in High Performance (HP) Banks
-- 7 Series
-- Xilinx HDL Language Template, version 2021.2
IOBUF_DCIEN_inst : IOBUF_DCIEN
generic map (
DRIVE => 12,
IOSTANDARD => "DEFAULT",
IBUF_LOW_PWR => "TRUE",
SLEW => "SLOW")
port map (
O => O, -- Buffer output
IO => IO, -- Buffer inout port (connect directly to top-level port)
DCITERMDISABLE => DCITERMDISABLE, -- DCI Termination enable input
I => I, -- Buffer input
IBUFDISABLE => IBUFDISABLE, -- Input disable input, high=disable
T => T -- 3-state enable input, high=input, low=output
-- End of IOBUF_DCIEN_inst instantiation
// IOBUF_DCIEN: Single-ended Bi-directional Buffer with Digital Controlled Impedance (DCI)
// and Input path enable/disable
// May only be placed in High Performance (HP) Banks
// 7 Series
// Xilinx HDL Language Template, version 2021.2
.DRIVE(12), // Specify the output drive strength
.IBUF_LOW_PWR("TRUE"), // Low Power - "TRUE", High Performance = "FALSE"
.IOSTANDARD("DEFAULT"), // Specify the I/O standard
.SLEW("SLOW"), // Specify the output slew rate
.USE_IBUFDISABLE("TRUE") // Use IBUFDISABLE function, "TRUE" or "FALSE"
) IOBUF_DCIEN_inst (
.O(O), // Buffer output
.IO(IO), // Buffer inout port (connect directly to top-level port)
.DCITERMDISABLE(DCITERMDISABLE), // DCI Termination enable input
.I(I), // Buffer input
.IBUFDISABLE(IBUFDISABLE), // Input disable input, high=disable
.T(T) // 3-state enable input, high=input, low=output
// End of IOBUF_DCIEN_inst instantiation
- See the 7 Series FPGA SelectIO Resources User