LPC54606 SCTimer change period problem

luimarma — Mon, 16 Oct 2023 15:12:34 GMT

Hello,

I am working with SCTimer to generate a PWM signal.

This signal I need to change the period and duty cycle frequently.

I have created a function in fs_timer library using the code of " SCTIMER_UpdatePwmDutycycle".

The function works when stepping in debug mode step by step, but when runing normal it stops generating the pulses. I am missing abything needed to change the match register and do not break anything?

The following is the function code used:

void SCTIMER_UpdatePwmPeriod(SCT_Type *base, sctimer_out_t output, sctimer_pwm_mode_t mode, uint32_t pwmFreq_Hz, uint8_t dutyCyclePercent, uint32_t srcClock_Hz, uint32_t event) { assert(0U != srcClock_Hz); assert(0U != pwmFreq_Hz); assert((uint32_t)output < (uint32_t)FSL_FEATURE_SCT_NUMBER_OF_OUTPUTS); assert(1U == (base->CONFIG & SCT_CONFIG_UNIFY_MASK)); status_t status = kStatus_Fail; status_t status2; uint32_t period, pulsePeriod = 0; uint32_t sctClock = srcClock_Hz / (((base->CTRL & SCT_CTRL_PRE_L_MASK) >> SCT_CTRL_PRE_L_SHIFT) + 1U); uint32_t periodEvent = 0, pulseEvent = 0; uint32_t reg; uint32_t periodMatchReg, pulseMatchReg; bool isHighTrue = (0U != (base->OUT[output].CLR & (1UL << (event + 1U)))); if ((s_currentEvent + 2U) <= (uint32_t)FSL_FEATURE_SCT_NUMBER_OF_EVENTS) { /* Calculate PWM period match value */ if (mode == kSCTIMER_EdgeAlignedPwm) { period = (sctClock / pwmFreq_Hz) - 1U; } else { period = sctClock / (pwmFreq_Hz * 2U); } /* For 100% dutycyle, make pulse period greater than period so the event will never occur */ if (dutyCyclePercent >= 100U) { pulsePeriod = period + 2U; /* Set the initial output level base on output mode */ if (isHighTrue) { base->OUTPUT |= (1UL << (uint32_t)output); } else { base->OUTPUT &= ~(1UL << (uint32_t)output); } } else { pulsePeriod = (uint32_t)(((uint64_t)period * dutyCyclePercent) / 100U); } /* Retrieve the match register number for the PWM period */ periodMatchReg = base->EV[event].CTRL & SCT_EV_CTRL_MATCHSEL_MASK; /* Retrieve the match register number for the PWM pulse period */ pulseMatchReg = base->EV[event + 1U].CTRL & SCT_EV_CTRL_MATCHSEL_MASK; /* Stop the counter before updating match register */ SCTIMER_StopTimer(base, (uint32_t)kSCTIMER_Counter_U); /* Update dutycycle */ base->MATCH[periodMatchReg] = period; base->MATCHREL[periodMatchReg] = period; base->MATCH[pulseMatchReg] = pulsePeriod; base->MATCHREL[pulseMatchReg] = pulsePeriod; /* Restart the counter */ SCTIMER_StartTimer(base, (uint32_t)kSCTIMER_Counter_U); } }

Re: LPC54606 SCTimer change period problem

Alice_Yang — Thu, 19 Oct 2023 06:49:12 GMT

Hello @luimarma

How about low the change frequency, it means delay the time before change period.

Alice

LPC MicrocontrollersのトピックRe: LPC54606 SCTimer change period problem

LPC54606 SCTimer change period problem

Re: LPC54606 SCTimer change period problem