S32K Input Capture

[Shruthi_C]

Hi Team, 

We are using S32K146 microcontroller, we need any one input pin as Input capture pin, can you please suggest me with which module should I configure?

If I use FTM as signal measurement, am I able to achieve input capture function? Or shall I use ic_pal functionality?

Please support

Thanks 
Shruthi C

[Shruthi_C]

Hi, 

Can I get any input for interrupt enabled FTM pin as input capture

Thanks

Shruthi C

[PetrS]

Hi,

the most common and efficient way is to configure FTM in input capture mode and use pin which has FTM functionality. Each FTM channel can be configured for input capture mode, where it captures the timer value on an edge (rising, falling, or both) of the input signal. This is commonly used for measuring: signal period, pulse width, frequency.

The IC PAL driver allows to detect the input signal and measure pulse width or period of the channel input signal. It was designed to be portable across all platforms and IPs which support FTM , eMIOS, FLEXPWM and ETIMER.

So if you want full control and performance use FTM directly. If you want simpler code and portability use IC PAL.

BR, Petr

[Shruthi_C]

Hi Petr,

Thanks for your neat clarification.

Can I use these functions to initialize FTM pin as input capture 
`FTM_DRV_Init()`
`FTM_DRV_InitInputCapture()`

And install an IRQ handler for capturing the pulse occurrence 

`INT_SYS_InstallHandler(FTM0_Ch0_Ch1_IRQn, PWM_InputCapture_IRQHandler, NULL)`

Please support

Thanks 
Shruthi C

[PetrS]

Hi,

yes, those functions should be enough. SDK driver enables FTM channel interrupt, right handler should be assigned from startup, I think. If not right handler is FTM0_Ch0_Ch1_IRQHandler.

The FTM_DRV_GetInputCaptureMeasurement is called to get captured value.

BR, Petr

[Shruthi_C]

Hi Petr,

Im unable to use  INT_SYS_InstallHandler(FTM0_Ch0_Ch1_IRQn, PWM_InputCapture_IRQHandler, NULL);  function  as its taking default handler and not taking this handler FTM0_Ch0_Ch1_IRQn

My configurations are 

/* Global configuration of flexTimer_ic_1 InitConfig */

ftm_user_config_t flexTimer_ic_1_InitConfig =

{

    {

        true,    /* Software trigger state */

        false,  /* Hardware trigger 1 state */

        false,  /* Hardware trigger 2 state */

        false,  /* Hardware trigger 3 state */

        false, /* Max loading point state */

        false, /* Min loading point state */

        FTM_SYSTEM_CLOCK, /* Update mode for INVCTRL register */

        FTM_SYSTEM_CLOCK, /* Update mode for SWOCTRL register */

        FTM_SYSTEM_CLOCK, /* Update mode for OUTMASK register */

        FTM_SYSTEM_CLOCK, /* Update mode for CNTIN register */

        false, /* Automatic clear of the trigger */

        FTM_UPDATE_NOW, /* Synchronization point */

    },

        FTM_MODE_INPUT_CAPTURE, /* Mode of operation for FTM */

        FTM_CLOCK_DIVID_BY_1, /* FTM clock prescaler */

        FTM_CLOCK_SOURCE_SYSTEMCLK,   /* FTM clock source */

        FTM_BDM_MODE_11, /* FTM debug mode */

        false,    /* Interrupt state */

        false     /* Initialization trigger */

};

/* Input capture configuration for flexTimer_ic_1 */

ftm_input_param_t flexTimer_ic_1_InputCaptureConfig =

{

    1U, /* Number of channel configurations */

    65535U, /* Maximum count value */

    flexTimer_ic_1_InputCaptureChannelConfig /* Channels configuration*/

};

/* Channels configuration structure for flexTimer_ic_1 input capture */

ftm_input_ch_param_t flexTimer_ic_1_InputCaptureChannelConfig[1] =

{

    {

        0U, /* Channel id */

        FTM_SIGNAL_MEASUREMENT, /* Input capture operation mode */

        FTM_RISING_EDGE, /* Edge alignment mode */

        FTM_FALLING_EDGE_PERIOD_MEASUREMENT, /* Signal measurement operation type */

        0U, /* Filter value */

        false, /* Filter state (enabled/disabled) */

        true, /* Continuous measurement state */

        NULL, /* Vector of callbacks  parameters for channels events */

        NULL /* Vector of callbacks for channels events */

    }

};

[PetrS]

Hi,

if you need to install handler again you should have 

extern void FTM0_Ch0_Ch1_IRQHandler(void);

INT_SYS_InstallHandler(FTM0_Ch0_Ch1_IRQn, FTM0_Ch0_Ch1_IRQHandler, NULL);

BR, Petr

[Shruthi_C]

Hi, 

Yes I do have that function defined, but after that the function call goes to infinite loop, and it will run further 

The whole system will not work, 

Thanks

Shruthi C

[PetrS]

Hi,

there is SDK example you can refer to directly (ftm_signal_measurement).
Or share simplified project showing the issue.

BR, Petr

[Shruthi_C]

HI,

In SDK example I referred to directly (ftm_signal_measurement).
In this example they did not used Interrupt method they used polling method then they called FTM_DRV_GetInputCaptureMeasurement 

Im looking for FTM signal measurement with interrupt, once input capture recognizes the signal, I need interrupt to be triggered and call FTM_DRV_GetInputCaptureMeasurement function in ISR

Can u pls provide code for this 

Thanks 
Shruthi C

[PetrS]

Hi,

driver is using interrupt for capture event, only not shown in example directly.
I modified FTM IC setting to use one shot mode and add Callback, which is called from driver interrupt.

See attached for modified main.c of ftm_signal_measurement_s32k146 demo.

BR, Petr

[Shruthi_C]

Hi, 

Thanks for your support, and code snippet, I will check 

T&R, 

Shruthi C