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import hdl coder fails, why?

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Gary
Gary on 15 Apr 2023
Commented: Kiran Kintali on 17 Apr 2023
I have the code below in verilog that implements cordic algorithm
`timescale 10 ns / 10 ns
module cordic_test
(
clk,
x,
y,
rst,
enable,
angle
);
input clk,rst,enable;
input [15:0] x,y;
output reg [15:0] angle;
reg signed [15:0] r,s,rnew,snew;
reg [4:0] i;
wire[0:15] tanLUT_fixed={16'h4000,16'h25c8,16'h13F6,16'hA22,16'h0516,16'h028B,16'h0145,16'h00A2,16'h51,16'h29,16'h14,16'hA,16'h5,16'h3,16'h2,16'h1};
always@(posedge clk)
if (!rst)
begin
rnew<=0;
snew<=0;
end
else if (enable==1)
begin
r<=x;
s<=y;
end
else begin
for(i=0;i<=15;i=i+1)
begin
if(s>0) // CW // Error: Multiple assignments on signal 'r' is not supported.
//Hdl Import parse failed.
begin
rnew<=r+(s>>i);
snew<=(s-(r>>i));
r<=rnew;
s<=snew;
angle<=(angle+tanLUT_fixed[i]);
end
else //CCW
begin
rnew<=(r-(s>>i));
snew<=(s+(r>>i));
r<=rnew;
s<=snew;
angle<=(angle-tanLUT_fixed[i]);
end
end
end
endmodule
. While importing through hdl coder, I get the error mesage "Multiple assignments on signal 'r' is not supported. Hdl Import parse failed. ". What could be wrong. Synthesizes well.

Answers (1)

Kiran Kintali
Kiran Kintali on 16 Apr 2023
This is a limitaiton of importhdl feature. In general only subset of verilog is convertible to Simulink using this feature.
  2 Comments
Gary
Gary on 16 Apr 2023
What corrections need to be done in the code?
Kiran Kintali
Kiran Kintali on 17 Apr 2023
What version of MATLAB are you using?
There is 128bit limitation for the import capability.
wire[0:15] tanLUT_fixed={16'h4000,16'h25c8,16'h13F6,16'hA22,16'h0516,16'h028B,16'h0145,16'h00A2,16'h51,16'h29,16'h14,16'hA,16'h5,16'h3,16'h2,16'h1};

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