“Software Compare” mode - timer interrupt is triggered at every TPM2_MOD value, and not at TPM2_C0V value

anand-k — Thu, 31 Oct 2013 13:33:51 GMT

Hello,

I was trying to generate timer interrupt on TPM2 of KL15 processor.

I used following function in setting up the timer interrupt.

void Tpm2Init(void)

{

//! Status and Control Register (TPM2_SC)

//! - Clear status and control register

TPM2_SC = (uint32_t)0x00000000;

//! Modulo Register (TPM2_MOD)

// TODO: Update these values based on power modes

//! - Period value is 10 milli seconds / (1/6MHz) = 60000

TPM2_MOD = (uint32_t)0x0000EA60;

//! Channel Status and Control Register (TPM2_C0SC)

//! - Enable channel interrupt [CHIE = 1]

//! - TPM Channel disabled [MSB = 0, MSA = 1, ELSB = 0, ELSA =0]

TPM2_C0SC = (uint32_t)0x00000050;

//! Channel Value (TPM2_C0V)

// TODO: Update these values based on power modes

//! - Period value is 1 milli second / (1/6MHz) = 6000

TPM2_C0V = (uint32_t)0x00001770;

//! Status and Control Register (TPM2_SC)

//! - Timer Overflow Interrupt Enable [TOIE = 0]

//! - LPTPM counter operates in up counting mode [CPWMS = 0]

//! - LPTPM counter increments on every LPTPM counter clock [CMOD = 1]

//! - Prescaler Factor Selection is divide by 4 [PS = 2]

TPM2_SC = (uint32_t)0x0000000A;

}

I checked and found out that timer interrupt is triggered for every 10 milli seconds with the above mentioned code (at TPM2_MOD value) and not at TPM2_C0V value.

I would like to know whether TPM2_C0V will be used in “Software Compare” mode.

In “SIM_SOPT2” register MCGFLLCLK is selected as TPM clock source and I have configured MCGFLLCLK as 24 MHz.

Could anyone help me on this?

Thanks in advance,

Regards,

Anand

Re: “Software Compare” mode - timer interrupt is triggered at every TPM2_MOD value, and not at TPM2_C0V value

Hui_Ma — Wed, 13 Nov 2013 03:06:25 GMT

Hi Anand,

The reason is you aren't correct set TPM mode to output compare, please check below picture, which need [ELSnB:ELSnA] with correct setting (not all 0).

And you also enable timer overflow interrupt, which will generate interrupt when MOD value reached.

Wish it helps.

B.R.

Ma Hui

Kinetis Microcontrollersのトピック“Software Compare” mode - timer interrupt is triggered at every TPM2_MOD value, and not at TPM2_C0V value

“Software Compare” mode - timer interrupt is triggered at every TPM2_MOD value, and not at TPM2_C0V value

Re: “Software Compare” mode - timer interrupt is triggered at every TPM2_MOD value, and not at TPM2_C0V value