Why do I use eMios to capture a low-frequency signal of 4hz, the acquisition result is random, not

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Why do I use eMios to capture a low-frequency signal of 4hz, the acquisition result is random, not

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zp001
Contributor III
 
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lm_rt_614
Contributor I

Hello all. I've been having the same issue. 

I need to be able to measure frequencies from 1Hz.

My core clock is 160MHz, Emios Mcl Clk Div Val is 256, Emios Mcl Master Bus Prescaler is DIV_16. For Emios Prescaler I tried setting it to both EMIOS_PRESCALER_DIVIDE_1 and EMIOS_PRESCALER_DIVIDE_16, but it doesn't make any difference. 

So the total frequency for the counter is 160.000.000/256/16 = 39062.5 Hz
When measuring the period between two rising edges at 1000 Hz, the period is 39 as expected. At 100 Hz, the period is about 390 as expected. At 10 Hz I start getting issues because instead of the expected period of about 3900, I get random results. At this point I'm still far from the Emios Mcl Default Period which is set to 65535. I'm using eMIOS0 CH6 which is G type and Counter bus F.

I appreciate any suggestions. Kind regards.

 

 

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