AR# 38213

Design Assistant for XST - Help resolving "HDLCompiler:634:Net does not have a driver" warnings

Description

Refer to this Answer Record for help resolving a "HDLCompiler:634:Net does not have a driver" warning.

Note: This Answer Record is a part of the Xilinx Solution Center for XST (Xilinx Answer 38927). The Xilinx Solution Center for XST is available to address all questions related to XST. Whether you are starting a new design or troubleshooting a problem, use the Solution Center for XST to guide you to the right information.

Solution

This message appears when the Net or Reg does not have a driver.

WHAT NEXT:

Make surethe Net in question is connectedto a source, so that it can drive the net, and re-run XST.

EXAMPLE:

Consider the following RTL:

module top (din, clk, rst, out);
input din;
input clk;
input rst;
output out;

reg temp_reg;
reg OutData;

always @(posedge clk, posedge rst) begin
if(rst)
OutData <= temp_reg;
else
OutData <= din;
end

assign out = OutData;
endmodule

In the above example,the register 'temp_reg' is not driven by a source (driver).

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Linked Answer Records

Master Answer Records

Answer Number	Answer Title	Version Found	Version Resolved
38927	Xilinx Solution Center for XST	N/A	N/A

Associated Answer Records

Answer Number	Answer Title	Version Found	Version Resolved
40379	Design Assistant for XST Help understanding the XST report to resolve errors\warnings	N/A	N/A

AR# 38213
Date	12/15/2012
Status	Active
Type	General Article
Devices	Virtex-5 FXT Virtex-5 LX Virtex-5 LXT More Virtex-5 SXT Virtex-5 TXT Virtex-5Q Virtex-5QV Virtex-6 CXT Virtex-6 HXT Virtex-6 LX Virtex-6 LXT Virtex-6 SXT Virtex-7 Less
Tools	ISE Design Suite - 11.5 ISE Design Suite - 12.1 ISE Design Suite - 12.2 More ISE Design Suite - 12.3 ISE Design Suite - 13.1 Less

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