Examples

This example shows how to generate a Xilinx ® System Generator for DSP Black Box block from a MATLAB® HDL design.

Introduction

HDL Coder can generate a System Generator Black Box block and configuration file from your MATLAB HDL design. After designing an algorithm in MATLAB for HDL code generation, you can then integrate it into a larger system as a Xilinx System Generator Black Box block.

HDL Coder places the generated Black Box block in a Xilinx System Generator (XSG) subsystem. XSG subsystems work with blocks from both Simulink® and Xilinx System Generator, so you can use the generated black box block to build a larger system for simulation and code generation.

MATLAB Design

The MATLAB code in the example implements a simple FIR filter. The example also shows a MATLAB testbench that exercises the filter.

design_name = 'mlhdlc_fir';
testbench_name = 'mlhdlc_fir_tb';

1. Design: mlhdlc_fir

2. Test Bench: mlhdlc_fir_tb

Create a New Folder and Copy Relevant Files

Execute the following lines of code to copy the necessary example files into a temporary folder.

mlhdlc_demo_dir = fullfile(matlabroot, 'toolbox', 'hdlcoder', 'hdlcoderdemos', 'matlabhdlcoderdemos');
mlhdlc_temp_dir = [tempdir 'mlhdlc_fir'];

% Create a temporary folder and copy the MATLAB files
cd(tempdir);
[~, ~, ~] = rmdir(mlhdlc_temp_dir, 's');
mkdir(mlhdlc_temp_dir);
cd(mlhdlc_temp_dir);

copyfile(fullfile(mlhdlc_demo_dir, [design_name,'.m*']), mlhdlc_temp_dir);
copyfile(fullfile(mlhdlc_demo_dir, [testbench_name,'.m*']), mlhdlc_temp_dir);

Simulate the Design

To simulate the design with the test bench to make sure there are no runtime errors before code generation, enter the following command:

mlhdlc_fir_tb

Create a New Project From the Command Line

To create a new project, enter the following command:

coder -hdlcoder -new fir_project

Next, add the file 'mlhdlc_fir.m' to the project as the MATLAB Function and 'mlhdlc_fir_tb.m' as the MATLAB Test Bench.

Click the Workflow Advisor button to launch the HDL Workflow Advisor.

Generate a Xilinx System Generator for DSP Black Box

To generate a Xilinx System Generator Black Box from a MATLAB HDL design, you must have Xilinx System Generator configured. Enter the following command to check System Generator availability:

xlVersion

In the Advanced tab of the Workflow Advisor, enable the Generate Xilinx System Generator Black Box option:

To generate code compatible with a Xilinx System Generator Black Box, set:

• 'Clock input port' to 'clk'

• 'Clock enable input port' to 'ce'

• 'Drive clock enable at' to 'DUT base rate'

Run Fixed-Point Conversion and Generate Code

Right-click the 'Code Generation' step and choose the 'Run to selected task' option to run all the steps from the beginning through HDL code generation.

Examine the Generated Model and Config File

A new model opens after HDL code generation. It contains a subsystem called DUT at the top level.

The DUT subsystem has an XSG subsystem called SysGenSubSystem, which contains:

• A Xilinx System Generator Black Box block

• A System Generator block

• Gateway-in blocks

• Gateway-out blocks

Notice that in addition to the data ports, there is a reset port on the black box interface, while 'clk' and 'ce' are registered to System Generator by the Black Box configuration file.

The configuration file and your new model are saved in the same directory with generated HDL code. You can open the configuration file by entering the following command:

edit('codegen/mlhdlc_fir/hdlsrc/mlhdlc_fir_FixPt_xsgbbxcfg.m');

You can now use the generated Xilinx System Generator Black Box block and configuration file in a larger system design.

Clean up the Generated Files

Run the following commands to clean up the temporary project folder.

mlhdlc_demo_dir = fullfile(matlabroot, 'toolbox', 'hdlcoder', 'hdlcoderdemos', 'matlabhdlcoderdemos');
mlhdlc_temp_dir = [tempdir 'mlhdlc_fir'];
clear mex;
cd (mlhdlc_demo_dir);
rmdir(mlhdlc_temp_dir, 's');