Primitive: Differential Bidirectional Buffer With Input Buffer Disable and On-die Input Termination Disable
- PRIMITIVE_GROUP: I/O
- PRIMITIVE_SUBGROUP: BIDIR_BUFFER
- Families: UltraScale, UltraScale+
Introduction
The IOBUFDS_DCIEN primitive is available in the HP I/O banks. It has an IBUFDISABLE port that can be used to disable the input buffer during periods that the buffer is not being used. The USE_IBUFDISABLE attribute must be set to TRUE and SIM_DEVICE to the appropriate value for this primitive to have the expected behavior that is specific to the architecture. The IOBUFDS_DCIEN primitive also has a DCITERMDISABLE port that can be used to manually disable the optional on-die receiver termination features (uncalibrated or DCI). See the UltraScale Architecture SelectIO Resources User Guide (UG571), "DCI Only available in the HP I/O Banks" and "Uncalibrated Input Termination in I/O Banks" sections for more details.
The IOBUFDS_DCIEN primitive can disable the input buffer and force the O output to the internal logic to a logic-Low when the IBUFDISABLE signal is asserted High and the output buffer is 3-stated (T = High). If the I/O is using an on-die receiver termination feature (uncalibrated or DCI), this primitive disables the termination legs whenever the DCITERMDISABLE signal is asserted High and the output buffer is 3-stated (T = High).
When the output buffer is 3-stated (T = High), the input buffer and any on-die receiver termination (uncalibrated or DCI) are controlled by IBUFDISABLE and DCITERMDISABLE, respectively. When the output buffer is not 3-stated (T = Low), the input buffer and any on-die receiver termination (uncalibrated or DCI) are disabled and force the O output (to the internal logic) to a logic-Low. These features can be combined to reduce power whenever the input is idle for a period of time.
I/O attributes that do not impact the logic function of the component, such as IOSTANDARD, DRIVE, and SLEW, should be supplied to the top-level port via an appropriate property. For details on applying such properties to the associated port, see the Vivado Design Suite Properties Reference Guide (UG912).
Port Descriptions
Port | Direction | Width | Function |
---|---|---|---|
DCITERMDISABLE | Input | 1 | Control to enable/disable DCI termination. This is generally used to reduce power in long periods of an idle state. |
I | Input | 1 | Input of OBUF. Connect to the logic driving the output port. |
IBUFDISABLE | Input | 1 | Disables input path through the buffer and forces to a logic Low. This feature is generally used to reduce power at times when the I/O is idle for a period of time. |
IO | Inout | 1 | Bidirectional diff_p port to be connected directly to top-level inout port. |
IOB | Inout | 1 | Bidirectional diff_n port to be connected directly to top-level inout port. |
O | Output | 1 | Output path of the buffer. |
T | Input | 1 | 3-state enable input signifying whether the buffer acts as an input or output. |
Design Entry Method
Instantiation | Yes |
Inference | No |
IP and IP Integrator Catalog | No |
Available Attributes
Attribute | Type | Allowed Values | Default | Description |
---|---|---|---|---|
SIM_DEVICE | STRING | "ULTRASCALE", "ULTRASCALE_PLUS", "ULTRASCALE_PLUS_ES1", "ULTRASCALE_PLUS_ES2" | "7SERIES" | Set the device version for simulation functionality. |
USE_IBUFDISABLE | STRING | "TRUE", "FALSE", "T_CONTROL" | "TRUE" | Set this attribute to "TRUE" to enable the IBUFDISABLE pin. |
VHDL Instantiation Template
Library UNISIM;
use UNISIM.vcomponents.all;
-- IOBUFDS_DCIEN: Differential Bidirectional Buffer With Input Buffer Disable and On-die Input Termination Disable
-- UltraScale
-- Xilinx HDL Language Template, version 2024.2
IOBUFDS_DCIEN_inst : IOBUFDS_DCIEN
generic map (
SIM_DEVICE => "ULTRASCALE", -- Set the device version for simulation functionality (ULTRASCALE)
USE_IBUFDISABLE => "TRUE" -- Enable/Disable the IBUFDISABLE pin (FALSE, TRUE, T_CONTROL)
)
port map (
O => O, -- 1-bit output: Buffer output
DCITERMDISABLE => DCITERMDISABLE, -- 1-bit input: DCI Termination Disable
I => I, -- 1-bit input: Buffer input
IBUFDISABLE => IBUFDISABLE, -- 1-bit input: Buffer disable input, high=disable
IO => IO, -- 1-bit inout: Diff_p inout (connect directly to top-level port)
IOB => IOB, -- 1-bit inout: Diff_n inout (connect directly to top-level port)
T => T -- 1-bit input: 3-state enable input
);
-- End of IOBUFDS_DCIEN_inst instantiation
Verilog Instantiation Template
// IOBUFDS_DCIEN: Differential Bidirectional Buffer With Input Buffer Disable and On-die Input Termination Disable
// UltraScale
// Xilinx HDL Language Template, version 2024.2
IOBUFDS_DCIEN #(
.SIM_DEVICE("ULTRASCALE"), // Set the device version for simulation functionality (ULTRASCALE)
.USE_IBUFDISABLE("TRUE") // Enable/Disable the IBUFDISABLE pin (FALSE, TRUE, T_CONTROL)
)
IOBUFDS_DCIEN_inst (
.O(O), // 1-bit output: Buffer output
.DCITERMDISABLE(DCITERMDISABLE), // 1-bit input: DCI Termination Disable
.I(I), // 1-bit input: Buffer input
.IBUFDISABLE(IBUFDISABLE), // 1-bit input: Buffer disable input, high=disable
.IO(IO), // 1-bit inout: Diff_p inout (connect directly to top-level port)
.IOB(IOB), // 1-bit inout: Diff_n inout (connect directly to top-level port)
.T(T) // 1-bit input: 3-state enable input
);
// End of IOBUFDS_DCIEN_inst instantiation