Why Output PWM Frequency in TMS320F28379D Controller dropping after deploying code ?

I am using the GPIO DO Block, and the PWM Frequency is 4 kHz. After generating code from Simulink, deploying the Code to the TMS320F28379D Controller, and then observing the PWM frequency on the Oscilloscope, which shows around 1.3 kHz. Why is the PWM frequency dropping?

Answer 1

[Kothuri]

Hi PANDIT DHANRAJ SURESH,

The GPIO DO Block which you are using is a Digital Output Block.

• If you are toggling the GPIO in software, the maximum frequency is limited by your model's step size and CPU speed.
• For accurate PWM, you should use dedicated PWM peripheral blocks provided in Simulink for the F28379D i.e, F2837xD ePWM block.
• These blocks configure the on-chip PWM peripherals, which can generate high-frequency PWM signals independent of the CPU and Simulink step size.

Please refer the below documentation for more info on ePWM block:

https://www.mathworks.com/help/ti-c2000/ref/epwmtype14.html