The MPC5748G chip cannot run after being powered on

[1009427882]

After being powered on, the MPC5748G cannot run.  When the reset pin (PIN 29) of MPC5748G-176QFP is continuously pulled down, the program will restart several times, after which it can return to normal.  May I ask whether this phenomenon is a hardware fault? Have you encountered similar problems?

[petervlna]

Hello,

Hmm, picture 1 and 2 seems to be the same picture. Am I wrong?

But please capture at least 200ms (not 8 as SWT is 20ms by default)

Best regards,

Peter

[1009427882]

Hello，

Yes, you're right. Picture 1 and picture 2 look the same. But the board in Picture 1 doesn't work, and the board in Picture 2 does.We couldn't find out what the problem was.

Attached is the picture you need.

[petervlna]

Hello,

Ok, then I am confused by your statement.

the program will restart several times, after which it can return to normal.

If the device is all the time in reset (as you present on the screenshots) how it can execute any program if core is in reset and not able to execute any instructions?

Also did you program anything to it?

and do you have custom HW or NXP evaluation board?

Are the supply voltages in datasheet specified range?

Best regards,

Peter

[1009427882]

Hello，

I'm sorry that I didn't describe it very clearly earlier. Our two boards have the same program and the same power supply. When they work normally, they will have LED lights on and the serial port will have data output. However, after board 1 is powered on, there is no LED light on and no data output. Board 2 is working properly. If the RESET pin of board 1 is continuously pulled down at this time (connect GND with jumper), the serial port of board 1 will have output showing that it has restarted several times, then we disconnect the jumper, and board 1 can running properly.

We have NXP MPC5748G evaluation board, I will check the power supply with the hardware engineer.

[petervlna]

Hello,

Could you post me a reset line measured by scope directly after power on reset?

There can be 2. scenarios.

1. reset escalation due to unlabeled SWT (default state from factory) -> discussed multiple time on forum.

2. you programmed corrupt data into HSM memory space -> bricked chip

Best regards,

Peter

[1009427882]

Thanks for your reply.

Picture 1 shows the RESET waveform of the chip that cannot be started.

Picture 2 shows the RESET waveform of a normal startup chip.

The chip in Picture 1 cannot run when it is powered on, and it cannot start even after repeated power-off and restart.  After pulling down the RESET pin level for a long time, it will restart several times, and then it will return to normal.  After it is restored to normal, it can run normally every time it is powered on and restarted.