FRDM KL26 TPM (Input Capture Mode)

[alexleonte]

Hello,

I have an FRDM-KL26 MCU and I'm writing a TPM/PWM driver, but can't accomplish it, so I have a couple of questions:

1.TPM0 has 5 channels.It is possible to use all of these channels as input capture ?

2.I already configured one channel for input capture mode, but i can`t clear TOF(timer overflow flag) register in ISR. ( it is because another overflow occurred before i cleared first time ?)

Example of ISR:

void Io_Tpm_Tpm1Isr(void)

{

    if(TPM_STATUS_REG(TPM1) & TPM_STATUS_TOF_MASK){                                            /* check if TOF is set */

        TPM1_SC |= TPM_SC_TOF_MASK;    /* Delete the TOF flag such that the IRQ ends */

    }

    if( TPM_STATUS_REG(TPM1) & TPM_STATUS_CH0F_MASK ){                                        /* CHANNEL 0*/

        TPM_CnSC_REG(TPM1,IO_TPM_CHANNEL0) |=  TPM_CnSC_CHF_MASK;                            /*Clear CHF  - event occurred */

    }else if(TPM_STATUS_REG(TPM1) & TPM_STATUS_CH1F_MASK){                                    /* CHANNEL 1*/

        TPM_CnSC_REG(TPM1,IO_TPM_CHANNEL1) |=  TPM_CnSC_CHF_MASK;                            /*Clear CHF  - event occurred */

    }

}

[kerryzhou · Accepted solution]

Hi ALex Leonte,

    Answer your two questions:

1.Yes, you can configure your 5 channels as the capture function.

2.When you enter in ISR, are you sure it is caused by the TOF, not the CHF? You can debug it in the ISR, find which interrupt flag caused this ISR.

If the ISR is caused by the TOF, you can clear it by write 1 to it.

Attached project is the KL26 TPM code, it can works ok on my FRDM-KL26, you can refer to it.

Wish it helps you!

If you still have question, please let me know.

Have a great day,
Jingjing

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[alexleonte]

Channel interrupt and overflow interrupt have same ISR - TPM0 ISR, TPM1 ISR, TPM2 ISR.

So in each ISR you have to find out who caused it .

Status and Compare register can tell us depending on wich  bit is 1.

In my project i use an overflow counter for duty cycle.