Hi Noah,
It's difficult to determine the exact cause of your issue, but I can provide some general advice on troubleshooting a PLL implementation on the TI C2000 F28379D.
Firstly, make sure that you have configured the PLL block correctly in your Simulink model. Check that the input signal to the PLL block has the correct amplitude and frequency, and that the PLL parameters (such as loop filter coefficients and NCO frequency) are set appropriately for your application.
Next, check the sample rate of your ADC and make sure that it is fast enough to capture the frequency components of the input signal. You may need to adjust the ADC settings or use a higher sampling rate to accurately capture the 60 Hz signal.
If you are still experiencing issues, try running the Simulink model in simulation mode with a fixed-step solver and a small time step (e.g. 1 microsecond). This will allow you to see the behavior of the PLL block in real-time and identify any issues with its performance.