How can I start up my board with a new & empty MPC5744p chip without causing the chip to brick.

[19627152]

Hello everybody,

I designed a control board referred to devkit-mpc5744p schematic_ Revb (SCH-29333).

When I first powered on the board, the RESET_B pin stayed low, and S32DS showed that the target may be entered reset escalation.

Then I removed U4(74LVC2GD8), U5(STM6315), R17, R18, and connected JTAG-RSTx directly to MCU-RSTx, kept  RESET_B pin with a pull-up resistance R15 to 3.3V. The problem remains，and I saw the RESET_B pin always stayed low from the oscilloscope when I powered on the board.

Is the chip "dead"? How can I reuse my board? or how can I start up my board?

Thank you very much!

[lukaszadrapa]

Hi,

if the reset is not released ever then it has nothing to do with reset escalation. Most likely, the reset is held by low voltage detectors. As a first step, I would check all supply rails.

https://www.nxp.com/docs/en/application-note/AN5267.pdf 

Regards,

Lukas