MPC5xxxのトピックPWM frequency calculation

PWM frequency calculation

Wen666 — Mon, 13 May 2024 08:09:58 GMT

Hello，

I would like to ask how the PWM frequency of MPC5744P is calculated.

The following figure shows the parameters I configured, where the frequency of MOTC_CLK is 200MHz,PWM_CLK is MOTC_CLK's 16-frequency division is 12.5MHz. The reload point of channel 0 of PWM is 4096, and the initial point is 0. According to the calculation, it should be 200MHz/16/4096=3.05KHz, but the actual measurement is only 2.4KHz, which is within the error range or there is a problem with my calculation?

Re: PWM frequency calculation

PetrS — Tue, 14 May 2024 06:07:41 GMT

Hi,

calculation is correct, but note max MOTC_CLK can be 160MHz. As you selected PLL0 for MOTC_CLK, most probably PLL0 is set to 160MHz. With this value you get 2,4KHz with your calculation.

BR, Petr

Re: PWM frequency calculation

Wen666 — Wed, 15 May 2024 01:26:37 GMT

OK,thanks.