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    • Timer2 maximum clock frequency on nucleo f401

    Posted by agassiandre on 2016-06-01 19:01

    Hi,

    reading the reference manual of stm32f401 processor (DM00096844), I would expect the timer 2 clock frequency to be the double of APB1 frequency when TIMPRE is 0, as I see in my case.
    I measure something as 42 MHz, meaning that I am generating a pwm from tim2 oc1 with a 50 % duty cycle and measuring the period of this pwm. I see a period that is double of what I expected.

    Questions:

    1) Is it correct to expect 84 MHz, or the timer clock maximum frequency is limited to the set APB1 frequency?

    2) Is there any other prescaler I am missing, for example in the OCx output?

    Regards.

    Reads: 14382
    Posted by agassiandre on 2016-06-07 10:19

    Hi,

    just to say, I found what the problem was.

    Actually I had another timer commanding the timer2, so the combination of master/slave determined half the frequency expected for the PWM.

    So, using only timer 2 I measured the expected times for PWM, using a prescaler that normalizes in us.

    Regards.