K32L2B21: generate PWM with variable frequency

nre — Thu, 27 May 2021 10:26:13 GMT

Hello, I need to generate a sound with a variable frequency during time (a siren).

I'm using uC K32L2B21, library SDK_2.9.0_K32L2B21xxxxA, MCUxpresso config tools v9, and TPM as a HW resource.
But I didn't find a way to dynamically change the frequency of a timer in a TPM library.
Pulse-Frequency-Modulation seems not supported on this chip.
I found only one timer API function that can be used for frequency changing (TPM_SetupPwm), but it entails constant period. What is the best way to generate variable frequency PWM?
Thank you in advance.

Re: K32L2B21: generate PWM with variable frequency

jingpan — Fri, 28 May 2021 10:39:22 GMT

Hi @nre ,

There is a inline function in fsl_tpm.h

static inline void TPM_SetTimerPeriod(TPM_Type *base, uint32_t ticks)
{
base->MOD = ticks;
}

Regards,

Jing

topic K32L2B21: generate PWM with variable frequency in MCUXpresso General

K32L2B21: generate PWM with variable frequency

Re: K32L2B21: generate PWM with variable frequency