topic Re: LS1043 PORRESET_B vs. HRESET_B difference to DDR controller in Layerscape

LS1043 PORRESET_B vs. HRESET_B difference to DDR controller

lingjun — Mon, 01 Jun 2026 08:47:19 GMT

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 ~

Re: LS1043 PORRESET_B vs. HRESET_B difference to DDR controller

yipingwang — Tue, 02 Jun 2026 02:05:00 GMT

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.

Re: LS1043 PORRESET_B vs. HRESET_B difference to DDR controller

lingjun — Tue, 02 Jun 2026 02:42:44 GMT

thank you very much. It helped me a lot.