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I am trying to toggle the red led using TPM0_interrupt on FRDM-KL43Z

Question asked by priyanka v on Apr 17, 2016
Latest reply on Apr 20, 2016 by Alice_Yang

HI,

 

I am trying to toggle the red led using TPM0 _interrupt on FRDM-KL43Z board. I selected MCGIRCLK(8MHZ) as TPM clock source.

Since the prescaler is 2, the TPM clock period is 0.25microseconds.I  am loading the TPM_MOD register with 8000 so that the ON and OFF period of led is 2ms .

But the problem is irrespective of the value loaded in the TPM_MOD register the ON and OFF periods are 16.80ms and 16ms respectively. The following is the code .

 

SIM_SCGC6 |= SIM_SCGC6_TPM0_MASK ; //enable the clock for TPM0 module

SIM_SOPT2        |= SIM_SOPT2_TPMSRC_MASK ; //MCGIRCLK as clock source

TPM0_CONF      |= TPM_CONF_DBGMODE_MASK ; // increment the counter in debug mode

TPM0_SC             |= TPM_SC_PS(1); //PRESCALER IS 2

TPM0_SC             |= TPM_SC_CPWMS_upcounting ; //up counting is selected(0x08u)

TPM0_CNT         |= TPM_CNT_COUNT_MASK ; //clear the counter value

TPM0_MOD       |= TPM_MOD_MOD(8000); // to get a delay of 2msec

TPM0_SC             |= TPM_SC_TOF_MASK ; // clear the interrupt flag

TPM0_SC             |= TPM_SC_TOIE_MASK; //enable the interrupt

TPM0_SC             |= TPM_SC_CMOD(2); //TPM counter increments on every TPM counter clock

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