Why is the "Closed Loop Control of a DC-DC Buck Converter" example not communicating with host model?

Hello,

I am currently working on the “Closed-loop control of DC-DC step-down converter” example provided by MathWorks:

https://www.mathworks.com/help/ti-c2000/ug/dc-dc-buck-converter.html

I followed all the instructions carefully, but unfortunately, the system is not operating as expected.

Issues observed:

• I am unable to read back the parameter values from the target model to the host model. I was trying to send parameter value from the host model and reading back the same parameter from the target.
• The oscilloscope shows unexpected/random waveforms instead of the expected response.
• I'm using LAUNCHXL-F28379D.
• I tested the setup with both MATLAB R2025a and MATLAB R2025b, but the issue persists in both versions.

Additional details:

• No modifications were made to the original model, except setting the correct COM port and Minor changes as shown in the attached images
• I am not using any BoosterPack (BOOSTXL-BUCKCONV).

I have attached relevant screenshots for reference.

I would appreciate any guidance or suggestions on what might be causing this issue.

Answer 1

[Samar]

Hi Mobasshir,

The detailed information and screenshot helped. Based on the setup and the observed behavior, the key reasons for the issues are:

1. BOOSTXL‑BUCKCONV is mandatory for this example: "The Closed‑Loop Control of DC‑DC Buck Converter" example is designed only for operation with the BOOSTXL‑BUCKCONV BoosterPack connected to the LAUNCHXL‑F28379D. Without the BoosterPack, ADC inputs are floating, leading to random/noisy waveforms and non‑meaningful feedback, which explains the oscilloscope behavior and unstable control.
2. Parameter read‑back not supported in the current setupIn this workflow, SCI/XCP is primarily intended for host‑to‑target parameter tuning, not round‑trip validation of the same parameter from the target. Reliable read‑back requires proper target‑side signal conditioning and valid plant feedback, which is missing without the BoosterPack hardware. Please refer the MathWorks Documentation given here: https://www.mathworks.com/help/ti-c2000/ug/parameter-tuning-external-mode.html
3. Expected behavior when running without power hardwareWhen the required power stage is not present, MathWorks recommends using simulation or HIL workflows, not direct hardware execution.

Recommendation

• Use the BOOSTXL‑BUCKCONV BoosterPack, or
• Run the controller in simulation/HIL mode if hardware is not available.

You can refer MATLAB Central discussion on SCI data handling in this buck example: https://www.mathworks.com/matlabcentral/answers/419321

Hope this helps!

Regards,

Samar