KEEPER - 2021.2 English

Vivado Design Suite 7 Series FPGA and Zynq-7000 SoC Libraries Guide (UG953)

Document ID
UG953
Release Date
2021-10-22
Version
2021.2 English

Primitive: KEEPER Symbol

Introduction

The design element is a weak keeper element that retains the value of the net connected to its bidirectional O pin. For example, if a logic 1 is being driven onto the net, KEEPER drives a weak/resistive 1 onto the net. If the net driver is then 3-stated, KEEPER continues to drive a weak/resistive 1 onto the net.

Port Descriptions

Port Direction Width Function
O Output 1-Bit Keeper output

Design Entry Method

Instantiation Yes
Inference No
IP Catalog No
Macro support No

This element can be connected to a net in the following locations on a top-level schematic file:

  • A net connected to an input IO Marker.

  • A net connected to both an output IO Marker and 3-statable IO element, such as an OBUFT.

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;

-- KEEPER: I/O Buffer Weak Keeper
--         7 Series
-- Xilinx HDL Language Template, version 2021.2

KEEPER_inst : KEEPER
port map (
   O => O     -- Keeper output (connect directly to top-level port)
);

-- End of KEEPER_inst instantiation

Verilog Instantiation Template


// KEEPER: I/O Buffer Weak Keeper
//         7 Series
// Xilinx HDL Language Template, version 2021.2

KEEPER KEEPER_inst (
   .O(O)     // Keeper output (connect directly to top-level port)
);

// End of KEEPER_inst instantiation

Related Information

  • See the 7 Series FPGA SelectIO Resources User Guide (UG471).