Filter ADC VDAC - Example Project

[Anonymous]

Hello everyone,

   

I have the CY8CKIT-059 Psoc 5LP development board and want to test some of the example projects to learn the programming of an psoc.

   

I followed the instructions of this video:

   

https://www.youtube.com/watch?v=oq8eQhvkceM

   

to replace the interrupt with an dma request.

       

With the interrupt the filter works well, but when i replace it with an dma request the filter inverts my signal and i do not know the problem.

       

I hope you can help to find the problem...

       

Best regards!

[Bob_Marlowe]

Welcome in the forum, Martin!

   

The filter block delivers signed numbers in the range of -128 to +127, the DAC only accepts positive numbers in the range 0 to 255. This is the reason why in the original project 128 was added to the filter result. Since this cannot be done with the DMA component you will have to stay with the interrupt driven solution.

       

Bob

   

PS Where in Germany are you located? I live near Bremen

[Anonymous]

Good morning Bob,

   

The idea with unsigned and signed numbers was one of my first thoughts.

   

But it cannot be the answer, because than the video of cypress with the replacement of the interrupt with the dma would be a fake...

       

Martin

   

PS: I'm living in Soest ( between Dortmund & Padaborn )

[Bob_Marlowe]

Which video (link please) are you referring to?

   

Wasn't there a "Konrad Zuse Museum" in / near Paderborn?

       

Bob

[Anonymous]

You can find it in die video library of cypress for the psoc 5lp... or on youtube with better resolution
.

   

Link:

   

http://www.cypress.com/video-library/PSoC/how-create-analog-filter-psoc-5lp/385626?tid=84511&sort_by...

   

https://www.youtube.com/watch?v=oq8eQhvkceM

   

Maybe he forgot something to mention in the video...

       

Never heard, that such a museum is in my near...

       

Edit:

   

Is it possible to use an "Xor" to add an 1000 0000 to the output of the filter ?

[Bob_Marlowe]

I would suggest to contact the author (Todd Dust) directly. Create a support case: At top of this page select "Design Support -> Create a Support Case" and describe your problem, mention Todd, the video etc..

   

Museum is part of the Nixdorf Museum, just googeld.

       

Bob