Digital Signal Processing (DSP) From Ground Up™ on Arm Processors

Advanced DSP Course- IIR filter programming

  • RTOS
  • DSP
  • IIR
  • FILTER
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Anirudh R
  • Post By Anirudh R
  • 2 years ago

I am looking at the IIR filter with direct form-2 programming with live sensor data. As I see, RTOS is used in the code to filter live sensor data.
Is it possible to do it without RTOS, by using timers and interrupts? My existing project is based on a non-RTOS code, and I'd like to know how to IIR filter ADC data in the same firmware without RTOS.

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3 comments

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YCC
2 years ago

Hi Anirudh,

You can apply a timer to trigger the ADC operation at periodic interval. This way, you can specify the sampling rate of the DSP system.

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Anirudh R
2 years ago

@Ninsaw Thanks for the reply.
I am unable to understand how your sampling rate of the sensor is taken in your firmware. As I see in the video, the ADC sampling happens in an RTOS task that runs continuously. I don't see any configuration of timing that sets the sampling frequency.
I am using this as a reference for my own Butterworth filter implementation to filter current sensors ADC of a DC-DC converter being sampled at 30kHz. I am calling the IIR function each ADC reading. Is this the right way? When plotting the raw and filtered signal, the filtered signal looks worse than the raw one.

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Ninsaw Gbati
2 years ago

Hi Anirudh,
All the projects can be implemented without an RTOS. You can do that by using one or more timer interrupts