IBUFE3 - 2024.1 English

UltraScale Architecture Libraries Guide (UG974)

Document ID
UG974
Release Date
2024-05-30
Version
2024.1 English

Primitive: Input Buffer with Offset Calibration and VREF Tuning

  • PRIMITIVE_GROUP: I/O
  • PRIMITIVE_SUBGROUP: INPUT_BUFFER
  • Families: UltraScale, UltraScale+

Introduction

The input buffer (IBUFE3) primitive is only supported in HP I/O banks. This primitive has functions similar to the IBUF_IBUFDISABLE with added controls for offset calibration and VREF tuning, along with input buffer disable (IBUFDISABLE). The offset calibration feature is accessed using the OSC_EN and OSC[3:0] ports. The VREF scan feature is accessed using the HPIO_VREF primitive in conjunction with IBUFE3.

I/O attributes that do not impact the logic function of the component, such as IOSTANDARD, and IBUF_LOW_PWR, should be supplied in XDC or 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). Attributes that impact the functionality, such as SIM_INPUT_BUFFER_OFFSET, must be supplied to the component via a generic_map (VHDL) or parameter (Verilog) to have the correct simulation behavior.

Port Descriptions

Port Direction Width Function
I Input 1 Diff_p Buffer Input. Connect to top-level p-side input 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.
O Output 1 Buffer output
OSC<3:0> Input 4 Offset cancellation value
OSC_EN Input 1 Offset cancellation enable
VREF Input 1 Vref input from HPIO_VREF

Design Entry Method

Instantiation Yes
Inference No
IP and IP Integrator Catalog No

Available Attributes

Attribute Type Allowed Values Default Description
SIM_DEVICE STRING "7SERIES", "ULTRASCALE" "ULTRASCALE" Set the device version for simulation functionality.
SIM_INPUT_BUFFER_OFFSET DECIMAL -50 to 50 0 Offset value for simulation purposes.
USE_IBUFDISABLE STRING "FALSE", "T_CONTROL", "TRUE" "FALSE" Set this attribute to "TRUE" to enable the IBUFDISABLE pin.

VHDL Instantiation Template

Unless they already exist, copy the following two statements and paste them before the entity declaration.
Library UNISIM;
use UNISIM.vcomponents.all;

-- IBUFE3: Input Buffer with Offset Calibration and VREF Tuning
--         UltraScale
-- Xilinx HDL Language Template, version 2024.1

IBUFE3_inst : IBUFE3
generic map (
   SIM_DEVICE => "ULTRASCALE_PLUS", -- Set the device version for simulation functionality (ULTRASCALE,
                                    -- ULTRASCALE_PLUS)
   SIM_INPUT_BUFFER_OFFSET => 0,    -- Offset value for simulation (-50-50)
   USE_IBUFDISABLE => "FALSE"       -- Enable/Disable the IBUFDISABLE pin (FALSE, TRUE, T_CONTROL)
)
port map (
   O => O,                     -- 1-bit output: Buffer output
   I => I,                     -- 1-bit input: Buffer input (connect directly to top-level port)
   IBUFDISABLE => IBUFDISABLE, -- 1-bit input: Buffer disable input, high=disable
   OSC => OSC,                 -- 4-bit input: Offset cancellation value
   OSC_EN => OSC_EN,           -- 1-bit input: Offset cancellation enable
   VREF => VREF                -- 1-bit input: Vref input from HPIO_VREF
);

-- End of IBUFE3_inst instantiation

Verilog Instantiation Template


// IBUFE3: Input Buffer with Offset Calibration and VREF Tuning
//         UltraScale
// Xilinx HDL Language Template, version 2024.1

IBUFE3 #(
   .SIM_DEVICE("ULTRASCALE_PLUS"), // Set the device version for simulation functionality (ULTRASCALE,
                                   // ULTRASCALE_PLUS)
   .SIM_INPUT_BUFFER_OFFSET(0),    // Offset value for simulation (-50-50)
   .USE_IBUFDISABLE("FALSE")       // Enable/Disable the IBUFDISABLE pin (FALSE, TRUE, T_CONTROL)
)
IBUFE3_inst (
   .O(O),                     // 1-bit output: Buffer output
   .I(I),                     // 1-bit input: Buffer input (connect directly to top-level port)
   .IBUFDISABLE(IBUFDISABLE), // 1-bit input: Buffer disable input, high=disable
   .OSC(OSC),                 // 4-bit input: Offset cancellation value
   .OSC_EN(OSC_EN),           // 1-bit input: Offset cancellation enable
   .VREF(VREF)                // 1-bit input: Vref input from HPIO_VREF
);

// End of IBUFE3_inst instantiation

Related Information

  • UltraScale Architecture SelectIO Resources User Guide (UG571)
  • Vivado Design Suite Properties Reference Guide (UG912)