I am seeking assistance with an issue involving the F280039C MCU on a high-voltage PMSM (Permanent Magnet Synchronous Motor) drive system (>1000V). Here’s the problem:

1. Setup:
   • I use a LaunchPad F280039C kit to upload code to the inverter’s F280039C MCU via a standard JTAG interface.
   • The code is developed in MATLAB/Simulink and flashed successfully in most cases.
2. Issue Description:
   • After uploading the code, the JTAG cable is disconnected, and the system is powered up (DC bus raised to rated voltage, followed by the MCU supply).
   • Recently, two critical problems occurred:
     • MCU Reset During Operation: When the JTAG cable is connected while the PMSM drive is running, the MCU resets and loses its code.
     • LaunchPad Failure: After several attempts (with JTAG disconnected during operation), the code upload process failed entirely, and the LaunchPad kit appears to be damaged (possibly burned out).
3. Key Observations:
   • The issue arises only when interacting with the JTAG interface under operational conditions (high-voltage active).
   • The LaunchPad kit worked fine initially but now seems non-functional after repeated attempts.

Could you please advise on:

• Potential causes for the MCU reset/code loss during JTAG connection under operation?
• Recommendations to avoid damaging the debugger/programmer in high-voltage environments?
• Any isolation or grounding precautions specific to JTAG in such systems?

Thank you for your support. I’d be happy to provide further details if needed.

 

Use separate grounds for the high-voltage and low-voltage sections, connecting them only at one point. Use TVS diodes, resistors, and shielding to protect the JTAG interface from high-voltage transients and EMI.