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ADC conversion speed too fast

Wahldo Engelbrecht
Prodigy 30 points


Hi

How can I limit my ADC sample speed to about 33kHz? My CPU speed is set to 60MHz. I dont know if im doing something wrong but the highest I can set the ACQPS value is 63. And according to my calculations it gives a sample rate of about 3MHz?

At the moment my ADC is initialized for simultaneous mode. Is it possible to count the amount of conversions (is it possible to count the amount of times the EOC bit is set)? Then if it is possibles i can count the samples and just use each x'th sample to decrease the sample rate.

Thanks in advance. 

  • 0
    Genius 4925 points

    Hi Wahldo,

    I think you are mixing different things... You can set your sampling speed to much slower rates than you stated, by setting for example a cputimer to the desired frequency and fire the ADCSOC every time you hit the timer period value. The ACQPS value determines only how long your sample and hold window is open, but this is not equal to the sampling rate!

    Best regards

    Andreas

  • 0 in reply to andreas von kaenel
    Prodigy 30 points

    Andreas

    Thanks a lot for the reply. I was mixing different things. I didn't understand the ADC setup but I think I do now.

    I'm going to set up a PWM signal at 33kHz and see if I can get it to trigger my SOC's. Which will solve my problem.  

    Thanks again.

    Wahldo