CIC to HDL conversion

Hi All,

When I try to generate HDL for a CIC filter I get the following error in the Workflow Manager : ??? Dimension 1 is fixed on the left-hand side but varies on the right ([3 x 1] ~= [:? x :?]).

Error in ==> CICDecimator Line: 1 Column: 1 ### Code generation failed: View Error Report

Error in Manager>wfa_generateCode at 0

The Error report shows as in the attached image.

Can anyone please help ? I am new to MATLAB-> HDL conversion.

PS : I do not have license for Filter Design HDL Coder, hence cant run the relevant example.

Answer 1

[Bharath Venkataraman]

I suggest using the CIC Decimation block in Simulink. This should generate HDL code.

[Khalid Mirza]

Thanks can you please send me a simple working model. I am not very familiar with Simulink. I tried using CIC Decimation block in Simulink, I have some difficulty setting it up.

Answer 2

[Gautham Sholingar]

1) It seems that the error you are observing is related to variable sized inputs being used to define the CIC_filter. You could try to resolve this error by pre-allocating the sizes of the variables/arrays used in this process.

2) You can take a look at the documentation page associated with the specific example you are using to identify if the Filter Design HDL Coder toolbox is needed for your workflow. This may/may not be needed depending on your workflow.

3) The following documentation page talks about the restrictions of generating HDL code from CIC decimation filters:

http://www.mathworks.com/help/hdlcoder/ref/cicdecimation.html

Please refer to this page to understand if you are running into one of the reported limitations:

4) If these approaches do not help in resolving the issue, you can contact MathWorks Technical Support in the UK using the following link:

https://www.mathworks.com/support/contact_us/?country_sort=UK&geoloc=United%2520Kingdom

[Khalid Mirza]

Thanks,

I fixed the input size related errors. However, during MATLAB -> HDL conversion, dsp.CICDecimator object was highlighted as incompatible for conversion. I finally managed to generate an HDL code for the CIC filter from Simulink.