Hello, i'm using K32L2B21 with MCUxpresso v.9.0.
When I start a PWM to generate a sound for a second time, an undesired sporadic pulse is generated at the beginning of the PWM sequence, as shown on the pic1. It could be because the duty cycle is 100% instead of 5% as expected.
Timer configuration is shown on pic2.
Initialization is following:
const tpm_config_t TPM1_config = {
.prescale = kTPM_Prescale_Divide_8,
.useGlobalTimeBase = false,
.triggerSelect = kTPM_Trigger_Select_0,
.triggerSource = kTPM_TriggerSource_External,
.enableDoze = false,
.enableDebugMode = false,
.enableReloadOnTrigger = true,
.enableStopOnOverflow = false,
.enableStartOnTrigger = false,
.enablePauseOnTrigger = false
};
const tpm_chnl_pwm_signal_param_t TPM1_pwmSignalParams[] = {
{
.chnlNumber = kTPM_Chnl_0,
.level = kTPM_HighTrue,
.dutyCyclePercent = 5U
}
};
void TPM1_init(void) {
TPM_Init(TPM1_PERIPHERAL, &TPM1_config);
TPM_SetupPwm(TPM1_PERIPHERAL, TPM1_pwmSignalParams, sizeof(TPM1_pwmSignalParams) / sizeof(tpm_chnl_pwm_signal_param_t), kTPM_EdgeAlignedPwm, 1000U, TPM1_CLOCK_SOURCE);
TPM_EnableInterrupts(TPM1_PERIPHERAL, kTPM_Chnl0InterruptEnable);
EnableIRQ(TPM1_IRQN);
}
main()
{
TPM_StartTimer(TPM1_PERIPHERAL, kTPM_SystemClock);
wait 10 s
TPM_StopTimer(TPM1_PERIPHERAL);
wait 2 s
TPM_StartTimer(TPM1_PERIPHERAL, kTPM_SystemClock); //<---- here the spark is generated
}
Dynamically i'm setting the sound period by
TPM_SetTimerPeriod(TPM1_PERIPHERAL, USEC_TO_COUNT(value, TPM_SOURCE_CLOCK));
