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mirco2
mirco2
Visitor II
August 12, 2015
Question

PWM with 1.5 MHz with STM32F411 Nucleo-Board

  • August 12, 2015
  • 2 replies
  • 1184 views
Posted on August 12, 2015 at 09:24

Hello,

i'm glad to be a member here in this forum. At the moment i am thinking about to buy a STM32F411 Nucleo-Board.  In this case i would like to ask you some question about this Board. I read many different articles about ''how to change the clock frequency'' but i couldn't find my answers. I would like to produce a PWM with a clock frequency of 1.5 MHz.

- Is this possible with the STM32F411 Nucleo-Board? If yes, what is the maximum resolution? 2-Bit?4-Bit? or higher? Are there any tables in which the output frequency in comparison with the resolution is?

- If i want to increase the clock frequency for example up to 100 MHZ. Do i have to include an external crystal? Or is it possible to change the internal PLL via software? If yes, how can i do that?

    This topic has been closed for replies.

    2 replies

    RomainR.
    RomainR.
    ST Employee
    August 12, 2015
    Posted on August 12, 2015 at 09:48

    First you should study the following documents:

    - STM32F411RE DataSheet

    - STM32F411RE Reference Manual

    I recommend the application note AN4013 which explain the features of Timer for all series of STM32.

    All documents are available

    http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1577/LN1877/PF260049?s_searchtype=partnumber#

    Is this feasible with the STM32F411 Nucleo-Board?

    If yes, what is the maximum resolution?

    2-Bit? 4-Bit?

    Higher gold?

    Are There Any qui tables in the output frequency in comparison with the resolution is?

     

    Yes this component has up to 8 TIMER.

    In 32bit and 16 bit

    Moreover, they also incorporate a variety of input / output mode Capture / Compare for this type of application.

    You should find alot of examples on Google

    .

    If i want to increase the clock frequency for example up to 100 MHZ. Do i have to include an external crystal? Or is it possible to change the internal PLL via software?

    Again you have to read the Reference manual and especially the chapter on RCC to understand how the STM32 Core and its peripherals are clocked

    To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
    Tesla DeLorean
    Tesla DeLorean
    Guru
    August 12, 2015
    Posted on August 12, 2015 at 16:35

    Thing to remember with the timers, and in fact all clocks in the STM32, all dividers are integer.

    100 MHz is not divisible by 1.5 MHz, 99 MHz is. You'd choose source clocks, and PLL settings accordingly.

    If you want to know how parts work you'll have to RTFM. The Reference Manual with the clock tree, and PLL settings being the first to review.
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