Hello,
is there a example for a FTMinput filter configuration?
I would like to debounce a pwm signal. Is the FTM filter useful for this application or should I implement the debouncing with software? Or is there a fitler by default? And are there pullup or pulldown resistors at the input pins?
This is the FTM configuration I am using.
/* - Dual-Edge Capture Mode */
void FTM0_Dual_Edge_Capture_Mode()
{
/* Enable clock for PORTD */
PCC->PCCn[PCC_PORTD_INDEX] = PCC_PCCn_CGC_MASK;
/* Select and enable clock for FTM0 */
PCC->PCCn[PCC_FTM0_INDEX] = PCC_PCCn_PCS(6) | PCC_PCCn_CGC_MASK;
PORTD->PCR[15] = PORT_PCR_MUX(2); // Set PTD15 for FTM0 - Channel0
S32_NVIC->ISER[FTM0_Ch0_Ch1_IRQn / 32] |= (1 << (FTM0_Ch0_Ch1_IRQn % 32)); // Enable interrupt
/* Enable dual-edge capture mode */
FTM0->COMBINE= FTM_COMBINE_DECAPEN0_MASK | FTM_COMBINE_DECAP0_MASK
| FTM_COMBINE_DECAPEN1_MASK | FTM_COMBINE_DECAP1_MASK;
/* Set CNTIN */
FTM0->CNTIN = FTM_CNTIN_INIT(0);
/* Select positive polarity pulse width measurement and enable continuous mode for FTM0_CH0 */
FTM0->CONTROLS[0].CnSC = FTM_CnSC_MSA_MASK | FTM_CnSC_ELSA_MASK;
FTM0->CONTROLS[1].CnSC = FTM_CnSC_ELSB_MASK | FTM_CnSC_CHIE_MASK;
/* Reset counter */
FTM0->CNT = 0;
/* Select clock */
FTM0->SC = FTM_SC_CLKS(1)
|FTM_SC_PS(7);
FTM0->MOD = 62500 -1 ; /* FTM1 counter final value (used for PWM mode) */
/* FTM1 Period = MOD-CNTIN+0x0001 ~= 62500 ctr clks */
/* 8MHz /128 = 62.5kHz -> ticks -> 1Hz */
}
