MATLAB: How to integrate HDL code from a MATLAB function and an FDATool filter in HDL Coder 3.2 (R2013a)

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I am trying to use Mathworks products to generate HDL code for my FPGA. I have successfully generated code from a MATLAB function, and also successfully generated code for a filter that I built using FDATool. I would like to combine these two components, such that a signal goes through my function and then goes through my filter (or vice versa). How do I combine these two components in HDL Coder 3.2 (R2013a)?

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There are several approaches that can be used to combine HDL code from a MATLAB function and from FDATool, depending on exactly how you would like to proceed. For example, you can try to integrate the function and the filter in MATLAB/Simulink and generate the HDL code as a single unit (this is probably a little easier), or you could try to generate the HDL code from both items separately and then combine them afterward.

1. The most straightforward way would be to bring both systems into Simulink and then generate the HDL code as a single unit. To do this, you can export the filter from FDATool to Simulink via File->Export to Simulink Model, and then click the “Realize Model” button. Then, you can port the MATLAB code into a MATLAB Function block. If you cascade these two blocks in Simulink, attach the necessary inports and outports, and create a subsystem from this, you can generate the HDL code as a single unit (right-click on the subsystem and go to HDL Code->Generate HDL for Subsystem).

2. If you would like to combine the HDL code using Mathworks tools after the HDL has already been generated, there is a “black box” approach, also using Simulink, which is detailed at the following link:

http://www.mathworks.com/help/releases/R2013a/hdlcoder/ug/black-box-implementation-for-subsystem-blocks.html

3. One additional way would be to design your filter using a system object and integrate this along with the function in a single M-file, and then generate HDL code from this combined MATLAB code. However, the caveat here is that not all of the current System objects are supported for HDL code generation. The list of supported System objects is available here:

http://www.mathworks.com/help/releases/R2013a/hdlcoder/ug/system-objects.html

If you start using Simulink, the HDL Workflow Advisor may come in handy. You can open this advisor by using the HDLADVISOR command, or going to Code->HDL Code->HDL Workflow Advisor in your Simulink model.

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MATLAB: M function converted into a VHDL with coder (Matlab R2012a)

MATLAB code is untimed code. It has no concept of time, and thus has no need to create or refer to a clocking signal within it. HDL Coder synthesizes a clock, clock enable, and reset when needed. These signals do not appear in the source code. They cannot be referenced by your MATLAB design; if you try to name-match the synthetic signal names, HDL Coder will (as you have seen) modify the name of the synthetic clock signals so that there is no name collision between the user MATLAB and the synthetic clocking signals.

HDL Coder can generate fairly sophisticated clocking patterns, depending on the optimizations and behavioral synthesis options chosen. For example, a large array declaration may infer a RAM. Design permitting, HDL Coder can schedule multiple accesses to this single RAM within a single clock cycle by using a multi-port RAM. Similarly, loops or other repeated structures can be streamed or shared, inferring hardware that runs at multiple rates.

If you have a straightforward design that uses a single clock rate, and you have no need for a clock enable, it can simply be tied high. Newer versions of HDL Coder (you are using the first release to support HDL code generation from MATLAB code) can detect and remove the clock enable in these circumstances.

I recommend taking a look at the examples provided with HDL Coder to understand how state elements are inferred based on your MATLAB code. The clocks themselves are taken care of by the tool.

MATLAB: How to disable the base rate interrupt and replace it with another interrupt, when working with Code Composer Studio and Embedded Coder 6.4 (R2013a)

There is no single checkbox that disables the base rate interrupt. However, there is a model that ships with Embedded Coder called "Field-Oriented Control of a Permanent Magnet Synchronous Machine F28335 Synchronized to ADC Interrupt" that provides an example of how to do this:

>> c28335_pmsmfoc_adcinterrupt

Note that this example builds upon the following Simulink Coder model:

>> rtwdemo_pmsmfoc_system

While using interrupts, the recommended practice is to place the blocks that the interrupt needs to trigger inside a Function-Call Subsystem. The only drawback is that you will lose the ability to use blocks (such as discrete integrators) that need absolute time in the function-call subsystems. However, you can replace these blocks with generic Simulink blocks by using unit delays. The following example uses this technique:

>> c28335pmsmfoc

In this example, there are PID blocks (e.g. Function-Call SubSystem/Generating Space Vectors/Generating Raw Space Vectors/control/PID Controller) that need integrators. If you look under the mask by right-clicking and going to “Look Under Mask”, you can see how the integrator is created with generic Simulink blocks.

You should be able to adapt these examples with your own model to disable the base rate interrupt and use another one instead.

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