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PSoC 5, 3 & 1 MCU

Anonymous
Not applicable

 Can Filter in PSoC process the analog signal? I didn't see any I/O ports of Filter.

   

The example project of Filter used DMA to transfer the digital signal. Is DMA necessary for using Filter?

   

 

   

Regards

   

Yudong

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Esteemed Contributor II

The filter component in PSoC3/5 is digital in nature, thus requiring an ADC first. To remove the burden for the CPU to transfer the converted values from ADC to Filter a DMA is appropiare thus freeing a lot of MIPS.

   

Nevertheless there are two LPFs within a PSoC3/5 which you may use, have a look at this thread http://www.cypress.com/?app=forum&id=2233&rID=63395 

   

 

   

Bob

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Esteemed Contributor

DMA is just one option for the filter data handling -

   

General Description

   

The customizer for the Filter component allows you to configure digital filters on
one or two data streams passed to the Digital Filter Block(DFB),using DMA,interrupts,
or polling to manage data flow. TheDFB’s 128 data and coefficientlocations are shared
as needed between the two filter channels.The customizer reports (but does not set)
the minimum bus clock frequency required to execute the filtering within the user-
declared sample interval.

   

 

   

The filter can perform BP, LP, HP, Band Stop.......

   

 

   

Regards, Dana.

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Anonymous
Not applicable

 Hi Bob and Dana,

   

I have read the example project of Filter. In that project, the cutoff frequency is 1KHz and input voltage range of ADC is 0 to 1.024V. My input sine wave is 900Hz and Vpp = 1V. So I expect to get sine wave on output terminal of VDAC which is equal in amplitude and frequency to the sine wave on input terminal of ADC. But my wave observed is not like the expection. Have I made any mistakes?

   

 

   

Regards

   

Yudong

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Anonymous
Not applicable

  I attached my project.

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Anonymous
Not applicable
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Anonymous
Not applicable

 I tried several times but failed to upload my files. My project is just the example project found in PSoC Creator.

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Anonymous
Not applicable

Have you zip the file?

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Anonymous
Not applicable

 Yes, I zipped the file.

   

Try again.

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Esteemed Contributor II

To upload a project here in Creator

   

Build -> Clean Project

   

File -> Create Workspace Bundle (minimal)

   

and then upload the resulting archieve here.

   

 

   

You do not get the signal you expect? A probabil might be that your 1V p-p signal might go below 0V. Check that with an oscilloscope.

   

 

   

Bob

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Esteemed Contributor II

When uploading does not work, try to use MS Internet Explorer, I've seen some issues with other browsers.

   

 

   

Bob

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Esteemed Contributor

If you sine wave is ground referenced you are violating common mode input range

   

of A/D or amplifier. In other words you need to level shift the sine wave to meet

   

the input CM range.

   

 

   

For example, if A/D Vref is Vssa to 2.048, single ended, optimally sine would go

   

from 0 Vdc to 2.048, that is its amplitude would be 2.048 and it would have a DC

   

offset of 1.024.

   

 

   

An easy way to offset input signals -

   

 

   

http://electronicdesign.com/analog/use-excel-calculate-d-level-shifter-resistor-values
 

   

Attached is Excel calculator for the R's.

   

 

   

Regards, Dana.

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Anonymous
Not applicable

Hi Yudong,

   

 

   

If you are unable to upload the project, please mail it to me (dasg@cypress.com). I'll post it on your behalf.

   

 

   

Regards,

   

Gautam

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