timer capture compare

[psandesh007]

Posted on June 24, 2013 at 15:22

Im going to capture simultaneously 4 input signals(same inputs for 4 channels) using Timer 8 by enabling all the interrupts in TIM->CCER register .. But it was not capturing correctly and im getting  channel number  2 and 4 continuously compared to 1 and 3 channels while im giving same frequency for all the channels..

please help me to solve this problem..

[Tesla DeLorean]

Posted on June 24, 2013 at 16:49

On which board/part?

Make sure you aren't using PWM Input Capture mode.

Regular input capture should be able to latch the time base independently on each of the 4 channels. The CCR registers are latches.

[psandesh007]

Posted on June 25, 2013 at 09:04

Thank you for your reply... I am using STM32F103ZET6 for frequency capturing. Is it possible to capture 4 channels of Timer8 at once by enabling all the 4 interrupts at same time. 

[psandesh007]

Posted on June 25, 2013 at 10:04

Im finding only TIM1_CC_IRQ Handler and TIM8_CC_IRQ Handler for frequency capturing in STM32F103ZET6, and im trying to do the same in TIM3 and TIM4 by configuring same as the TIM1 and TIM8,  but I don't know how to capture the frequency using these timers, can u please help me to overcome this problem..

[Tesla DeLorean]

Posted on June 25, 2013 at 14:09

TIM3_IRQHandler, the interrupts all share a common handler.

[Tesla DeLorean]

Posted on June 26, 2013 at 14:25

Not your part, but perhaps illustrative. [DEAD LINK /public/STe2ecommunities/mcu/Lists/STM32Discovery/Flat.aspx?RootFolder=/public/STe2ecommunities/mcu/Lists/STM32Discovery/PWM%20Input%20capture%20doesnt%20work%20on%20Ch34%20pair&FolderCTID=0x01200200770978C69A1141439FE559EB459D75800084C20D8867EAD444A5987D47BE638E0F&TopicsView=https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/AllItems.aspx&currentviews=32]https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/Flat.aspx?RootFolder=%2fpublic%2fSTe2ecommunities%2fmcu%2fLists%2fSTM32Discovery%2fPWM%20Input%20capture%20doesnt%20work%20on%20Ch34%20pair&FolderCTID=0x01200200770978C69A1141439FE559EB459D75800084C20D8867EAD444A5987D47BE638E0F&TopicsView=https%3A%2F%2Fmy.st.com%2Fpublic%2FSTe2ecommunities%2Fmcu%2FLists%2FSTM32Discovery%2FAllItems.aspx¤tviews=32

[psandesh007]

Posted on June 27, 2013 at 09:54

Thank you.. (STM32F103ZET6) Now it is capturing 6 channels 4 from TIM8(CH1 & CH2 & CH3 & CH4) and 2 from TIM1(CH1 & CH4) and if i gave 6th channels TIM1_CH1 or TIM1_CH4 then it will fluctuates all the other 5 channels .. And also if i increase the frequency of all channels expect channels CH2 and CH3 of TIM8,then it was capturing the lower frequencies of all other channels , if im keep on increasing TIM8_CH1 and TIM8_CH4 and TIM1_CH1, then TIM8_CH2 and TIM8_CH3 frequencies are fluctuating more... please help me to solve this problems.... below is the code

void TIM8_CC_IRQHandler(void)

{

if((TIM8->SR & 0x2)!=0)// && (TIM8->SR & 0x1000)!=0)

    {

        TIM8->SR&=0xEFFC;

        ch1_CAP=TIM8->CCR1;

        ch1_CAP2=TIM5->CNT;

        if(ch1_CAP2>=ch1_CAP3)

        {

            gl85_lsb_captval_CH1=((65535*ch1_CAP2)+ch1_CAP)-((65535*ch1_CAP3)+ch1_CAP1);

        }

        else

        {

               ch1_CAP3=65535-ch1_CAP3;

            gl85_lsb_captval_CH1=(65535*(ch1_CAP2+ch1_CAP3))+(ch1_CAP-ch1_CAP1);

        }

        ch1_CAP1=TIM8->CCR1;

        ch1_CAP3=TIM5->CNT;

        No_of_Captures85_ch1++;

        if(No_of_Captures85_ch1>1)

        {

            No_of_Captures85_ch1=0;

            gl_capture_ch85_flag=1;

            TIM8_CH1_CAP_FLAG=1;

        }

    }

    else if((TIM8->SR & 0x4)!=0)// && (TIM8->SR & 0x0800)!=0)

    {

        TIM8->SR&=0xF7FA;

        ch2_CAP=TIM8->CCR2;

        ch2_CAP2=TIM5->CNT;

        if(ch2_CAP2>=ch2_CAP3)

        {

            gl85_lsb_captval_CH2=((65535*ch2_CAP2)+ch2_CAP)-((65535*ch2_CAP3)+ch2_CAP1);

        }

        else

        {

               ch2_CAP3=65535-ch2_CAP3;

            gl85_lsb_captval_CH2=(65535*(ch2_CAP2+ch2_CAP3))+(ch2_CAP-ch2_CAP1);

        }

        ch2_CAP1=TIM8->CCR2;

        ch2_CAP3=TIM5->CNT;

        No_of_Captures85_ch2++;

        if(No_of_Captures85_ch2>2)

        {

            No_of_Captures85_ch2=0;

            gl_capture_ch85_flag=1;

            TIM8_CH2_CAP_FLAG=1;

        }

    }

    else if((TIM8->SR & 0x8)!=0)// && (TIM8->SR & 0x0400)!=0)

    {

        TIM8->SR&=0xFBF6;

        ch3_CAP=TIM8->CCR3;

        ch3_CAP2=TIM5->CNT;

        if(ch3_CAP2>=ch3_CAP3)

        {

            gl85_lsb_captval_CH3=((65535*ch3_CAP2)+ch3_CAP)-((65535*ch3_CAP3)+ch3_CAP1);

        }

        else

        {

               ch3_CAP3=65535-ch3_CAP3;

            gl85_lsb_captval_CH3=(65535*(ch3_CAP2+ch3_CAP3))+(ch3_CAP-ch3_CAP1);

        }

        ch3_CAP1=TIM8->CCR3;

        ch3_CAP3=TIM5->CNT;

        No_of_Captures85_ch3++;

        if(No_of_Captures85_ch3>2)

        {

            No_of_Captures85_ch3=0;

            gl_capture_ch85_flag=1;

            TIM8_CH3_CAP_FLAG=1;

        }    

    }

    else if((TIM8->SR & 0x10)!=0)// && (TIM8->SR & 0x0200)!=0)

    {

        TIM8->SR&=0xFDEE;

        ch4_CAP=TIM8->CCR4;

        ch4_CAP2=TIM5->CNT;

        if(ch4_CAP2>=ch4_CAP3)

        {

            gl85_lsb_captval_CH4=((65535*ch4_CAP2)+ch4_CAP)-((65535*ch4_CAP3)+ch4_CAP1);

        }

        else

        {

               ch4_CAP3=65535-ch4_CAP3;

            gl85_lsb_captval_CH4=(65535*(ch4_CAP2+ch4_CAP3))+(ch4_CAP-ch4_CAP1);

        }

        ch4_CAP1=TIM8->CCR4;

        ch4_CAP3=TIM5->CNT;

        No_of_Captures85_ch4++;

        if(No_of_Captures85_ch4>3)

        {

            No_of_Captures85_ch4=0;

            gl_capture_ch85_flag=1;

            TIM8_CH4_CAP_FLAG=1;

        }

    }

}

[Tesla DeLorean]

Posted on June 27, 2013 at 13:58

I'm not sure I'm invested in wading through that.

 

What frequency ranges are we talking about?

Don't use TIMx->SR &=  this is not how to clear status and causes hazards.

[psandesh007]

Posted on June 28, 2013 at 07:14

Thank u Clive now the code is working and we are talking about 5Hz-1KHz by cascading the timers.. Now also im clearing the status register like TIMx->SR&= .. But before im clearing 'Status Register' by writting '0' into it, that was clearing all the interrupts flag so i used this way.. Can u tell me the other method of clearing the status registers..

[Tesla DeLorean]

Posted on June 28, 2013 at 13:51

if (TIM8->SR & 2) // TIM_IT_CC1

    {

        TIM8->SR = ~2;

..

[psandesh007]

Posted on June 29, 2013 at 07:42

Thanks for your support..

Frequency is still fluctuating little if i use that math ..

        ch4_CAP=TIM3->CCR1;

        ch4_CAP2=TIM1->CNT;

        if(ch4_CAP2>=ch4_CAP3)

        {

            gl31_captval_CH4=((65535*ch4_CAP2)+ch4_CAP)-((65535*ch4_CAP3)+ch4_CAP1);

        }

        else

        {

               ch4_CAP3=65535-ch4_CAP3;

            gl31_captval_CH4=(65535*(ch4_CAP2+ch4_CAP3))+(ch4_CAP-ch4_CAP1);

        }

        ch4_CAP1=TIM3->CCR1;

        ch4_CAP3=TIM1->CNT

Can you Help me to do the math for both timers..