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Does anyone could give me a hint about using the dsp.HDLIFFT in my code for HDL Code Generation?

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Im trying to generate a OFDM symbol for HDL Code Generation.
My code is:
%Main function
[Xt,validOut] = MODEL(Data_In)
%QPSK Modulator
[x_re,x_im,ready] = qpsk(input);
%if the symbol is ready keep it in ram..for future dataprocessing like Selective Mapping
[x_re,~] = ram_re[x_re,..]
[x_im,~] = ram_re[x_im,..]
%calculate IFFT for Xk = xre + jx_im
[Xt,validOut] = HDLIFFT128(xk,validIn)
function HDLIFFT128 given as example in the Matlab Documentation:
function [yOut,validOut] = HDLIFFT128(yIn,validIn)
%HDLIFFT128
% Processes one sample of data using the dsp.HDLIFFT System object(TM)
% yIn is a fixed-point scalar or column vector.
% validIn is a logical scalar.
% You can generate HDL code from this function.
persistent ifft128
if isempty(ifft128)
ifft128 = dsp.HDLIFFT('FFTLength',128);
end
[yOut,validOut] = step(ifft128,yIn,validIn);
end
Test Bench for HDLIFFFT128
....
N=128
Xt = zeros(1,3*N);
validOut = false(1,3*N);
for loop = 1:1:N
[Xt(loop),validOut(loop)] = HDLIFFT128(complex(Yin(loop)),true);
end
for loop = N+1:1:3*N
[Xt(loop),validOut(loop)] = HDLIFFT128(complex(0),false);
end
...
Does anyone know why I need to use a 3*N (3*128) loop for getting the IFFT of the input signal (Yin is a 128 size vector)?. I tryed to use the test bench inside my main function but It dosen´t work for HDL Code Generation. So How can I use HDLIIFT128 function in my code?

Answers (1)

Kiran Kintali
Kiran Kintali on 22 May 2021
MATLAB Design
function [yOut,validOut] = HDLFFT128(yIn,validIn)
persistent fft128;
if isempty(fft128)
fft128 = dsp.HDLFFT('FFTLength',128);
end
[yOut,validOut] = fft128(yIn,validIn);
end
Instructions to generate HDL code from above MATLAB code
yIn = fi(complex(0,0), 1, 32, 24, hdlfimath); % compelx signed 32bit input with 24bit fraction length
validIn = true;
c = coder.config('hdl');
codegen -config c -args {yIn, validIn} HDLFFT128 -report
### Begin VHDL Code Generation
### Generating HDL Conformance Report HDLFFT128_hdl_conformance_report.html.
### HDL Conformance check complete with 0 errors, 0 warnings, and 0 messages.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_1/SimpleDualPortRAM_generic as SimpleDualPortRAM_generic.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_1/SDFCommutator1 as SDFCommutator1.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_1 as RADIX22FFT_SDF1_1.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_CTRL1_1 as RADIX22FFT_CTRL1_1.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF2_2/SDFCommutator2 as SDFCommutator2.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF2_2 as RADIX22FFT_SDF2_2.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_CTRL1_2 as RADIX22FFT_CTRL1_2.vhd.
### Working on HDLFFT128/dsp.HDLFFT/TWDLROM_3_1 as TWDLROM_3_1.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_3/Complex4Multiply as Complex4Multiply.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_3/SDFCommutator3 as SDFCommutator3.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_3 as RADIX22FFT_SDF1_3.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_CTRL1_3 as RADIX22FFT_CTRL1_3.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF2_4/SDFCommutator4 as SDFCommutator4.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF2_4 as RADIX22FFT_SDF2_4.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_CTRL1_4 as RADIX22FFT_CTRL1_4.vhd.
### Working on HDLFFT128/dsp.HDLFFT/TWDLROM_5_1 as TWDLROM_5_1.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_5/Complex4Multiply as Complex4Multiply_block.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_5/SDFCommutator5 as SDFCommutator5.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_5 as RADIX22FFT_SDF1_5.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_CTRL1_5 as RADIX22FFT_CTRL1_5.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF2_6/SDFCommutator6 as SDFCommutator6.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF2_6 as RADIX22FFT_SDF2_6.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_CTRL1_6 as RADIX22FFT_CTRL1_6.vhd.
### Working on HDLFFT128/dsp.HDLFFT/TWDLROM_7_1 as TWDLROM_7_1.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_7/Complex4Multiply as Complex4Multiply_block1.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_7/SDFCommutator7 as SDFCommutator7.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_SDF1_7 as RADIX22FFT_SDF1_7.vhd.
### Working on HDLFFT128/dsp.HDLFFT/RADIX22FFT_CTRL1_1 as RADIX22FFT_CTRL1_1_block.vhd.
### Working on HDLFFT128/dsp.HDLFFT as dsp_HDLFFT.vhd.
### Working on HDLFFT128 as HDLFFT128.vhd.
### Generating package file HDLFFT128_pkg.vhd.
### Generating Resource Utilization Report resource_report.html.
### Code generation successful: View report
>>

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