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developer2
developer2
Senior
August 7, 2013
Question

PWM pausing

  • August 7, 2013
  • 8 replies
  • 1329 views
Posted on August 07, 2013 at 13:52

Hi All,

i'm using on STM32F417 PWM on TIM4 CH2, i have successfully initialized PWM, i have there LED with blinking on 2Hz,

i would like to pause and i would like to return PWM to initial state with configured polarity,

is it possible with one command ?

when i use only TIM_Cmd( TIM4, DISABLE);

the LED stays in the last state, sometimes stays lighting and sometimes stays in off state,

Thank You for all replies,

Kind regards ...

#!telegraphing
    This topic has been closed for replies.

    8 replies

    Tesla DeLorean
    Tesla DeLorean
    Guru
    August 7, 2013
    Posted on August 07, 2013 at 14:11

    TIM4->CCR2 = 0;  Would be more predictable

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    developer2
    developer2Author
    Senior
    August 7, 2013
    Posted on August 07, 2013 at 14:59

    here is my source:

    DEBUG_LED_GREEN1_TIM4CH2(x)

    {

      if(x==0)

      {

       TIM_SetCompare2( TIM4, 0);

       TIM_Cmd( TIM4, DISABLE);

       TIM_CtrlPWMOutputs( TIM4, DISABLE );

      }

      else

      {

       TIM_SetAutoreload( TIM4, x);

       TIM_SetCompare2( TIM4, (x/2==0?1:(x/2)) );

       TIM_Cmd( TIM4, ENABLE);

      }

    }

    still no success :(

    i tried:

       TIM_Cmd( TIM4, DISABLE);

       TIM_SetCompare2( TIM4, 0);

       TIM_CtrlPWMOutputs( TIM4, DISABLE );

    and also:

       TIM_Cmd( TIM4, DISABLE);

       TIM_CtrlPWMOutputs( TIM4, DISABLE );

       TIM_SetCompare2( TIM4, 0);

    :(

    DAS.ANIL KUMAR
    DAS.ANIL KUMAR
    Associate II
    June 20, 2014
    Posted on June 20, 2014 at 09:22

    I have same problem.... i used tim1 ch4 and ch3 i want to start channel3 after 1 us  or delay betwwen ch3 and ch4  of 1 us ....plz help me ..

    thanks

    Tesla DeLorean
    Tesla DeLorean
    Guru
    June 20, 2014
    Posted on June 20, 2014 at 13:51

    The timers really don't work that way, there is a single counting element and the CCRx are just latches/comparators.

    If you want to impart some phase shift of one channel vs the next, use toggle mode, however this will always give you 50/50 duty unless you actively reprogram the TIMx->CCRx values ahead of the counter.
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    DAS.ANIL KUMAR
    DAS.ANIL KUMAR
    Associate II
    June 21, 2014
    Posted on June 21, 2014 at 08:14

    thank u for reply .............. how can i shift the phase  for 1 us delay.between these channel signal . which register value used for phase shift  ..i am using stvd and stm8s103.......thanks .

    Tesla DeLorean
    Tesla DeLorean
    Guru
    June 21, 2014
    Posted on June 21, 2014 at 14:28

    What's with the periods?

    This is an STM32 forum, if you have an STM8 question post it to that forum.

    If I had a 72 MHz system clock, with no prescaler 1us would be 72 ticks, and to get a phase shift in toggle mode you'd advance one CCRx by 72 with respect to the other.

    TIM1->CCR1 = N;

    TIM2->CCR2 = N + 72; // modulo period as required

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    DAS.ANIL KUMAR
    DAS.ANIL KUMAR
    Associate II
    June 23, 2014
    Posted on June 23, 2014 at 07:19

    thank u sir,   i didnot find phase shift in stm8 foroum thats why i am here.........i am using 16 Mhz internal freq.  i am generating  both signal with 10us for on and 8 us for off and continue and i want to 1 us second delay between these signal  or 2nd sinal start after 1us and continue.

    plz help me   thanks

    Tesla DeLorean
    Tesla DeLorean
    Guru
    June 23, 2014
    Posted on June 23, 2014 at 14:47

    thank u sir,   i didnot find phase shift in stm8 foroum thats why i am here.........i am using 16 Mhz internal freq.  i am generating  both signal with 10us for on and 8 us for off and continue and i want to 1 us second delay between these signal  or 2nd sinal start after 1us and continue.

     

    plz help me   thanks

    Then open a new question in the STM8 forum, the two platforms are not compatible.

    Failing that you'll have 2 rtfm.....

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