基于Matlab设计生成HDL/Verilog代码

本示例展示了如何创建HDL Coder项目并从MATLAB设计中生成代码。在这个例子中，你需要：
1、创建一个MATLAB HDL Coder项目。
2、将设计和测试台文件添加到项目中。
3、启动HDL Workflow Advisor进行MATLAB设计。
4、执行定点转换和生成HDL代码。

一、Matlab设计FIR滤波器

MATLAB设计的mlhdlc_sfir是一个简单的对称FIR滤波器。

design_name = ‘mlhdlc_sfir’;
testbench_name = ‘mlhdlc_sfir_tb’;

在Matlab中新建两个脚本，命名为上述两个文件：

mlhdlc_sfir.m代码如下：

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% MATLAB design: Symmetric FIR Filter
% 
% Introduction:
%
% We can reduce the complexity of the FIR filter by leveraging its symmetry. 
% Symmetry for an n-tap filter implies, coefficient h0 = coefficient hn-1, 
% coefficient, h1 = coefficient hn-2, etc. In this case, the number of 
% multipliers can be approximately halved. The key is to add the 
% two data values that need to be multiplied with the same coefficient 
% prior to performing the multiplication. 
%
% Key Design pattern covered in this example: 
% (1) Filter states represented using the persistent variables
% (2) Filter coefficients passed in as parameters
%   Copyright 2011-2019 The MathWorks, Inc.
%#codegen
function [y_out, delayed_xout] = mlhdlc_sfir(x_in,h_in1,h_in2,h_in3,h_in4)   
% Symmetric FIR Filter
% declare and initialize the delay registers
persistent ud1 ud2 ud3 ud4 ud5 ud6 ud7 ud8;
if isempty(ud1)
    ud1 = 0; ud2 = 0; ud3 = 0; ud4 = 0; ud5 = 0; ud6 = 0; ud7 = 0; ud8 = 0;
end
% access the previous value of states/registers
a1 = ud1 + ud8; a2 = ud2 + ud7;
a3 = ud3 + ud6; a4 = ud4 + ud5;
% multiplier chain
m1 = h_in1 * a1; m2 = h_in2 * a2;
m3 = h_in3 * a3; m4 = h_in4 * a4;
% adder chain
a5 = m1 + m2; a6 = m3 + m4;
% filtered output
y_out = a5 + a6;
% delayout input signal
delayed_xout = ud8;
% update the delay line
ud8 = ud7; 
ud7 = ud6;
ud6 = ud5;
ud5 = ud4;
ud4 = ud3;
ud3 = ud2;
ud2 = ud1;
ud1 = x_in;
end

二、FIR滤波器Matlab测试台

MATLAB测试台mlhdlc_sfir_tb对滤波器设计进行了验证。

mlhdlc_sfir_tb.m代码如下：

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% MATLAB test bench for the FIR filter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   Copyright 2011-2019 The MathWorks, Inc.
clear mlhdlc_sfir;
T = 2;
dt = 0.001;
N = T/dt+1;
sample_time = 0:dt:T;
df = 1/dt;
sample_freq = linspace(-1/2,1/2,N).*df;
% input signal with noise
x_in = cos(2.*pi.*(sample_time).*(1+(sample_time).*75)).';
% filter coefficients
h1 = -0.1339; h2 = -0.0838; h3 = 0.2026; h4 = 0.4064;
len = length(x_in);
y_out = zeros(1,len);
x_out = zeros(1,len);
for ii=1:len
    data = x_in(ii);
    % call to the design 'mlhdlc_sfir' that is targeted for hardware
    [y_out(ii), x_out(ii)] = mlhdlc_sfir(data, h1, h2, h3, h4);