topic Re: input capture in Kinetis Microcontrollers

input capture

pandi — Thu, 18 Jan 2024 11:48:26 GMT

@ xiangjun_rong

how to configure input capture mode KV31F512VLL12 guide me and if you have sample program give to me help for us.

Thank you

PANDI

Re: input capture

pandi — Thu, 18 Jan 2024 14:11:18 GMT

@ xiangjun_rong

I `m trying this code not working if any changes let me know

void TIM1_init(void) {

SIM->SCGC5 |= SIM_SCGC5_PORTB(1);

PORTB->PCR[0] = PORT_PCR_MUX(0x3); // Set pin as ALT3 (TIM1_CH1)

SIM->SCGC6 |= SIM_SCGC6_FTM1(1);

FTM1->SC = 0;

FTM1->MOD = 1999;

FTM1->CONTROLS[1].CnSC = FTM_CnSC_MSB_MASK | FTM_CnSC_ELSB_MASK;

FTM1->CONTROLS[1].CnV = 1000;

FTM1->SC = FTM_SC_PS(7) | FTM_SC_TOF(1);

}

void TIM2_init(void) {

// Enable clock for PORTA

SIM->SCGC5 |= SIM_SCGC5_PORTA_MASK;

PORTA->PCR[1] = PORT_PCR_MUX(0x3); // Set pin as ALT3 (TIM2_CH1)

SIM->SCGC6 |= SIM_SCGC6_FTM2(1);

FTM2->SC = 0;

FTM2->CONTROLS[1].CnSC = FTM_CnSC_ELSA_MASK | FTM_CnSC_ELSB_MASK |FTM_CnSC_CHIE_MASK;

FTM2->SC = FTM_SC_PS(7) | FTM_SC_TOF(1);

NVIC_EnableIRQ(FTM2_IRQn);

}

void FTM2_IRQHandler() {

// Clear channel flag

FTM2->CONTROLS[1].CnSC &= ~FTM_CnSC_CHF_MASK;

if (gap == 0) {

counter0 = FTM2->CONTROLS[1].CnV;

gap = 1;

} else {

counter1 = FTM2->CONTROLS[1].CnV;

if (counter1 > counter0) {

Counter = counter1 - counter0;

Frequency = 10000 / Counter;

} else {

Counter = counter1 + 0xFFFF - counter0 + 1;

Frequency = 10000 / Counter;

}

counter0 = counter1;

}

PANDI

Re: input capture

xiangjun_rong — Mon, 22 Jan 2024 08:05:37 GMT

Hi, Pandi,

This is the capture mode configuration for FTM. You have to configure the FTM1_CHx as FTM1 function in the PORTx_PCRy register so that you can connect the captured signal to the FTM0_CHx pin.

Hope it can help you

XiangJun Rong

Re: input capture

pandi — Mon, 22 Jan 2024 11:58:51 GMT

@xiangjun_rong

i`m trying but did not get frequency value .please you have to give input frequency calculation code guide me

This code TIM1 PWM generation and TIM2 to get frequency if any changes you have to guide me and you have change this code

void TIM1_init(void) {

SIM->SCGC5 |= SIM_SCGC5_PORTB(1);

PORTB->PCR[0] = PORT_PCR_MUX(0x3); // Set pin as ALT3 (TIM1_CH1)

SIM->SCGC6 |= SIM_SCGC6_FTM1(1);

FTM1->SC = 0;

FTM1->MOD = 1999;

FTM1->CONTROLS[1].CnSC = FTM_CnSC_MSB_MASK | FTM_CnSC_ELSB_MASK;

FTM1->CONTROLS[1].CnV = 1000;

FTM1->SC = FTM_SC_PS(7) | FTM_SC_TOF(1);

}

void TIM2_init(void) {

// Enable clock for PORTA

SIM->SCGC5 |= SIM_SCGC5_PORTA_MASK;

PORTA->PCR[1] = PORT_PCR_MUX(0x3); // Set pin as ALT3 (TIM2_CH1)

SIM->SCGC6 |= SIM_SCGC6_FTM2(1);

FTM2->SC = 0;

FTM2->CONTROLS[1].CnSC = FTM_CnSC_ELSA_MASK | FTM_CnSC_ELSB_MASK |FTM_CnSC_CHIE_MASK;

FTM2->SC = FTM_SC_PS(7) | FTM_SC_TOF(1);

NVIC_EnableIRQ(FTM2_IRQn);

}

void FTM2_IRQHandler() {

// Clear channel flag

FTM2->CONTROLS[1].CnSC &= ~FTM_CnSC_CHF_MASK;

if (gap == 0) {

counter0 = FTM2->CONTROLS[1].CnV;

gap = 1;

} else {

counter1 = FTM2->CONTROLS[1].CnV;

if (counter1 > counter0) {

Counter = counter1 - counter0;

Frequency = 10000 / Counter;

} else {

Counter = counter1 + 0xFFFF - counter0 + 1;

Frequency = 10000 / Counter;

}

counter0 = counter1;

}

Thankyou

PANDI

Re: input capture

xiangjun_rong — Tue, 23 Jan 2024 09:03:30 GMT

Hi, Pandi,

Can you enter FTM2_IRQHandler() if you connect a captured signal?

XiangJun Rong

Re: input capture

pandi — Tue, 23 Jan 2024 09:09:54 GMT

@xiangjun_rong

yes ,In captured frequency forTIM1 but did not working this program FTM2_IRQHandler() to get frequency value not working pls you have to guide me if any sample program give to me

Thank you

PANDI

Re: input capture

xiangjun_rong — Tue, 23 Jan 2024 09:14:54 GMT

Hi,

Pls confirm if you can enter the FTM2_IRQHandler()? it does not matter if you computation is correct or not, but it is first step that you can enter FTM2_IRQHandler() if you connect a captured signal to FTM2_CHx pin.

XiangJun Rong

Re: input capture

pandi — Tue, 23 Jan 2024 09:22:50 GMT

@xiangjun_rong

yes,TIM1 output pin to TIM2 input pin captured signal in connected.

PANDI

Re: input capture

xiangjun_rong — Tue, 23 Jan 2024 09:25:24 GMT

Hi, Pando,

can you enter the FTM2_IRQHandler()?

XiangJun Rong

Re: input capture

pandi — Tue, 23 Jan 2024 09:30:09 GMT

yes

@xiangjun_rong

void FTM2_IRQHANDLER(void) {

uint32_t intStatus;

/* Reading all interrupt flags of status register */

intStatus = FTM_GetStatusFlags(FTM2_PERIPHERAL);

FTM_ClearStatusFlags(FTM2_PERIPHERAL, intStatus);

currentCaptureValue = FTM2->CONTROLS[0].CnV;

period = currentCaptureValue - previousCaptureValue;

if (period > 0) {

capturedFrequency =SystemCoreClock/period; //SystemCoreClock / period;

} else {

capturedFrequency = 0;

}

previousCaptureValue = currentCaptureValue;

/* Add for ARM errata 838869, affects Cortex-M4, Cortex-M4F

Store immediate overlapping exception return operation might vector to incorrect interrupt. */

#if defined __CORTEX_M && (__CORTEX_M == 4U)

__DSB();

#endif

}

PANDI

Re: input capture

xiangjun_rong — Thu, 25 Jan 2024 04:58:30 GMT

Hi,

Okay, you can enter the FTM2_IRQHANDLER(), i suggest you use single edge to test the period, instead of dual edge. In general, the period is constant.

Hope it can help you

XiangJun Rong