Can someone please highlight, what is the maximum limit of etpu channel frequency?
In the application notes, it states
freq (uint32_t): The frequency of the PWM output in Hz. The range of this parameter is determined by the complete system but normally should be between 1 Hz and 100 kHz.
However I have to generate PWM of 300Khz, and When I generate, I get a square wave in which the vertical edges are not vertical.The rise and fall in voltage should be instantaneous but here there is a distinct lengthening of the rise and fall times plus a certain amount of rounding of the waveform.
I tried to use different value of slew rate while configuring SIU_PCR register.
Waveform generated by my code is similar to one attached.
Hi, timing of output pads with slew rate control you have defined in
MPC5777C Microcontroller Data Sheet Data Sheet, Rev. 11, 04/2017,
Figure 5 and Table 9.
AN2849 (document describing eTPU PWM function) speaks about 100kHz.
If we take into account that the PWM function was written for MPC5554, its eTPU max frequency is 66MHz and max eTPU frequency for MPC5777C is 100MHz (in eTPU or normal clock mode), we could simply estimate maximum frequency around 150kHz, but it is given by eTPU code execution time, not by pad performance.