LS1043 PORRESET_B vs. HRESET_B difference to DDR controller

[lingjun]

Hi NXP expert : 

     I have a board that uses the LS1043 processor, and this board's CPU may have power integrity issues. I've found that when the DDR controller causes a CPU exception due to power integrity problems, the watchdog HRESET_B reset sometimes fails to successfully reset the CPU. Only a  PORRESET_B power reset can successfully reset it.

    I would like to know: for the DDR controller of the LS1043, what is the difference between these PORRESET_B and HRESET_B resets?

   thanks a lot ~

[yipingwang · Accepted solution]

• PORRESET_B = full chip cold reset
  → Resets everything, including DDR controller logic, PHY, internal state machines, PLLs, and I/O calibration.

• HRESET_B = core/system warm reset
  → Resets CPU cores and most digital logic, but does NOT fully reset DDR PHY and some analog / training state.

Therefore: If DDR or its PHY enters an invalid state (e.g., due to power integrity causing training corruption), HRESET_B cannot recover it, but PORRESET_B can.

[lingjun]

thank you very much. It helped me a lot.