CFGLUT5 - 2021.2 English

UltraScale Architecture Libraries Guide (UG974)

Document ID
UG974
Release Date
2021-10-22
Version
2021.2 English

Primitive: 5-input Dynamically Reconfigurable Look-Up Table (LUT)

  • PRIMITIVE_GROUP: CLB
  • PRIMITIVE_SUBGROUP: LUT
  • Families: UltraScale, UltraScale+

Introduction

This element is a runtime, dynamically reconfigurable, 5-input look-up table (LUT) that enables the changing of the logical function of the LUT during circuit operation. Using the CDI pin, a new INIT value can be synchronously shifted in serially to change the logical function. The O6 output pin produces the logical output function, based on the current INIT value loaded into the LUT and the currently selected I0-I4 input pins. Optionally, you can use the O5 output in combination with the O6 output to create two individual 4-input functions sharing the same inputs or a 5-input function and a 4-input function that uses a subset of the 5-input logic (see the following tables). This component occupies one of the eight LUT6 components within a SLICEM.

To cascade this element, connect the CDO pin from each element to the CDI input of the next element. This will allow a single serial chain of data (32-bits per LUT) to reconfigure multiple LUTs.

Port Descriptions

Port Direction Width Function
CDI Input 1 Reconfiguration data serial input.
CDO Output 1 Reconfiguration data cascaded output (optionally connect to the CDI input of a subsequent LUT).
CE Input 1 Active-High reconfiguration clock enable.
CLK Input 1 Reconfiguration clock.
O5 Output 1 4-LUT output.
O6 Output 1 5-LUT output.
LUT Inputs: Logic inputs to the programmable look-up table.
I0 Input 1 Logic inputs to the programmable look-up table.
I1 Input 1 Logic inputs to the programmable look-up table.
I2 Input 1 Logic inputs to the programmable look-up table.
I3 Input 1 Logic inputs to the programmable look-up table.
I4 Input 1 Logic inputs to the programmable look-up table.

Design Entry Method

Instantiation Yes
Inference No
IP and IP Integrator Catalog No

Available Attributes

Attribute Type Allowed Values Default Description
INIT HEX Any 32-bit HEX value All zeroes Specifies the initial logical expression of this element.
IS_CLK_INVERTED BINARY 1'b0 to 1'b1 1'b0 Indicates whether the CLK is active-High or active-Low.

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;

-- CFGLUT5: 5-input Dynamically Reconfigurable Look-Up Table (LUT)
--          UltraScale
-- Xilinx HDL Language Template, version 2021.2

CFGLUT5_inst : CFGLUT5
generic map (
   INIT => X"00000000",    -- Initial logic function
   IS_CLK_INVERTED => '0'  -- Optional inversion for CLK
)
port map (
   CDO => CDO, -- 1-bit output: Reconfiguration cascade
   O5 => O5,   -- 1-bit output: 4-LUT
   O6 => O6,   -- 1-bit output: 5-LUT
   CDI => CDI, -- 1-bit input: Reconfiguration data
   CE => CE,   -- 1-bit input: Reconfiguration enable
   CLK => CLK, -- 1-bit input: Clock
   -- LUT Inputs inputs: Logic inputs
   I0 => I0,
   I1 => I1,
   I2 => I2,
   I3 => I3,
   I4 => I4
);

-- End of CFGLUT5_inst instantiation

Verilog Instantiation Template


// CFGLUT5: 5-input Dynamically Reconfigurable Look-Up Table (LUT)
//          UltraScale
// Xilinx HDL Language Template, version 2021.2

CFGLUT5 #(
   .INIT(32'h00000000),    // Initial logic function
   .IS_CLK_INVERTED(1'b0)  // Optional inversion for CLK
)
CFGLUT5_inst (
   .CDO(CDO), // 1-bit output: Reconfiguration cascade
   .O5(O5),   // 1-bit output: 4-LUT
   .O6(O6),   // 1-bit output: 5-LUT
   .CDI(CDI), // 1-bit input: Reconfiguration data
   .CE(CE),   // 1-bit input: Reconfiguration enable
   .CLK(CLK), // 1-bit input: Clock
   // LUT Inputs inputs: Logic inputs
   .I0(I0),
   .I1(I1),
   .I2(I2),
   .I3(I3),
   .I4(I4)
);

// End of CFGLUT5_inst instantiation

Related Information

  • See the UltraScale Architecture Configurable Logic Block User Guide (UG574).