MPC5777C RSTOUT permanently asserted

darq · ‎03-27-2022

Hello,

We have an issue with MPC5777C not recovering after short time voltage drop. We use MC35FS6513 as our SBC chip so the setup is almost the same as on the evaluation board MPC5777C-516DS. During cranking procedure when the battery charge is low, we see that voltage drops below what is required by SBC. The result is that we observe around 40ms voltage drop on 5V and 1,25V delivered to the microcontroller. As a result the microcontroller resets which is expected. Unfortunately after around 1s we loose communication with the microcontroller because as we discovered, the RSTOUT signal from the microcontroller is permanently asserted. What can be the reason for that and how can i proceed with investigation of this issue any further?

Any help would be greatly appreciated.

Best regards

darq · ‎04-20-2022

Could i ask for some further suggestions?

Best regards

petervlna · ‎03-28-2022

Hello.

Unfortunately after around 1s we loose communication with the microcontroller because as we discovered, the RSTOUT signal from the microcontroller is permanently asserted.

And after the initial reset from low voltage regulator, you are able to boot micro and after 1s it went to reset?

Could you be more specific?

Best regards,

Peter

darq · ‎03-28-2022

The times vary a bit but it is as the attached picture presents. The red signal is RSTOUT and the green one is 5V power supply to the micro. The 1,25V looks the same as 5V, after initial drop it is constant.

Oysterminate · ‎03-30-2022

The times vary a bit but it is as the attached picture presents. The red signal is RSTOUT and the green one is 5V power supply to the micro. The 1,25V looks the same as 5V, after initial drop it is constant. publix passport

Very informative post. I really do hope and pray this stuff works!

petervlna · ‎03-29-2022

Hello,

Thanks for measurement.

It looks like the reset is triggered from micro on some other event after some time.

What is the status of Reset Status Register (SIU_RSR) after second reset?

Reset Status Register (SIU_RSR) will give you an reset source.

Best regards,

Peter

saichinnala · ‎06-24-2023

i want to use spi from mcu to control sbc but i did not find configuration sdk for sbc, can you please solve the issue to configure sbc in mpc5777c_devb board

darq · ‎04-12-2022

Hi,

Any further suggestions?

Best regards

petervlna · ‎04-22-2022

Hello,

Has there been any progress from your side on this issue?

I can see that after voltage drop micro is restarted and then it will run into reset after some time, in this time do you see anything in your safety mechanisms on micro? FCCU faul, SWT timeout, etc..

Is you SW running as expected?

I see your 5V is fine and you stating also core voltage is fine so the reset is coming from your application. Do you see anything in FCCU alarm state, any expection?

You will need to attach in this time to device with debugger, or to write SW to log the reset and FCCU sources in this time to som NVM memory.

Best regards,

Peter

darq · ‎04-07-2022

I have checked today and i can confirm. RSTOUT signal is staying low for minutes (indefinitely?) and the debug session cannot be started.

darq · ‎04-04-2022

Hi,

Thank you for your answer. As far a i remember i could not start debug session after this event but i would have to confirm. The setup to reproduce this is quite hard to book so it may take some time before i post some reply.

Best regards