Hi Ethan,

Let me look into this further and get back to you in 1-2 days. Thank you.

Best Regards,

Aishwarya

Part Number: TMS320F2800156-Q1

Tool/software:

Problem description

Date：2025.3.20

Background：During products functional testing after mass production, some products are running abnormally.

2      Cause analysis

1)      By observing the LED on the product, it was found that the MCU will continuously reset；

2)      Using an oscilloscope to detect the XRSN pin, it was found that the pin would be pulled down, and then the MCU reset.

3)      This MCU is welded on a normal product ，and the MCU still reset.

4)      Read RESC register data and send the data through CAN communication, it was found that the MCU was reset by NMIWDRSn.

5)      Read NMISHDFLG register data and send the data through CAN communication, it was found that the Shadow NMI Flags is CLOCKFAIL;

6)      The CLOCKFAIL is generated by clock (OSCCLK) failure detection module.

7)      Used an oscilloscope to test the external crystal oscillator, it founnds that the crystal oscillator is working normally.

8)      Turn off the MCD(missing clock detect) function, the product run normally;

Based on the above analysis, it is a problem with the internal missing clock detection circuit of the MCU.

Please help analyzed the cause of the damage.

Attached is the schematic.thanks!

SCH_TMS.pdf

Hi Zoey,

I see this question was already asked, so I will go ahead and merge these threads together. Thank you.

Best Regards,

Aishwarya

Hi Aishwarya

Please give some comments, thanks!

Hi  Aiswarya,

Pls give some advice? Thanks！

And it is similar as this problem.

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1126440/tms320f280025-pll-reference-clock-lost-detection-triggered-missing-clock-detect-not/4184003?tisearch=e2e-sitesearch&keymatch=SYSREF_LOST_MCD_EN#4184003 

Ethan / Zoey,

Could you please provide details on your clock configurations? Sending a snippet of code that configures the clock as well as screenshots of registers would be helpful to understand if there is a software cause to this. 

Best Regards,

Aishwarya 

Zoey / Ethan,

Could you confirm the following details regarding the hardware and software:

Hardware - 

• Both when MCD is enabled and disabled, can you provide images of the scope measurement for SYSCLK/8 on XCLKOUT? Are these scope readings correct and as expected?
• Can you provide a scope shot of X1/X2 to see if the crystal drive levels are as expected?  
• Does the XTAL take a long time to start up?
• In regard to the clock circuit...
  • Why was a shunt resistor (R36) added and why is it equal to 1 MOhms? Does MCD work as expected when the shunt resistor is removed?
  • What is the part number for the XTAL (Q200)?
  • What is the ESR? Maximum should be 45 or 75 for a 16 MHZ XTAL. Refer to this section for more information.

Software - 

• Was the application code migrated from an another (older) device to F280015x? Were there any modifications to the clock related code? If so, what were they?
• Could you please provide details on your clock configurations? Looking for a snippet of code that configures the clock as well as screenshots of the values in the registers.
• When the MCD function is turned off, can you confirm whether when the application code is running, all the functions are also executing correctly?

Best Regards,

Aishwarya