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Hello:
I am using IPWM mode to measure external PWM pulses, in actual testing I found that when I meet the requirements of measuring low-frequency PWM signals a few HZ frequency, measurement of high-frequency PWM signals error will be very large, when to meet the high-frequency signals measurement accuracy, then the measurement of low-frequency signals will be an overflow event, there is no way that I can meet the low-frequency and high-frequency PWM pulses measurement at the same time. Hope to get some suggestions.
IPWM timer value is 16bit for 65536. So you may need to change the value setting for 5Hz and 30KHz since the dynamic freq range between 5Hz and 30KHz is quite large...
When I realize the stable acquisition of 3-10HZ PWM pulses, the error when measuring 30KHZ or even 40KHZ may be more than 20 %
I now want to realize 5HZ-30KHZ PWM pulse acquisition (duty cycle 50 %), the current configuration I get the 5HZ case of the period of 50000, so my corresponding clock frequency is roughly 250000 at this time I collect 30KHZ PWM pulse acquisition of the period of 8,9, at this time the conversion over the frequency of 27777-31250, the error is relatively large! If I want to improve the collection accuracy I need to reduce the value of Clock Divider Value; Master Bus Prescaler; Master Bus Alternate Prescaler, accordingly, when the measurement of 5HZ there may be overflow events, I do not know if my understanding is correct.
Hi@xuanming
please take a look at this post, if still have any question, please let me know,
https://community.nxp.com/t5/S32M-Knowledge-Base/S32M27x-S32K3-eMIOS-Usage/ta-p/2129760
How large the PWM measurement error will be ? You may need to check the counter bus channel you relied on when you measure the PWM pulse width like prescaler value etc..