First ESP32-P4 board bringup - power problems

[mikeselectricstuff]

Hi - I'm trying to get my first ESP32-P4 board running. It is basically a copy of the Waveshare WIFI6-TOUCH-LCD-XC board (Schematic : https://files.waveshare.com/wiki/ESP32- ... matic.pdf] ), with a few parts omitted (camera, audio, USB-Serial)

The immediate issues I see are that DCDC_EN is low, and the LDO outputs are incorrect.

LDO values:
V01 1.10V
V02 1.08V
V03 40mV
V04 3.30V
VddHP is at 1.13v
I am seeing some boot text from the UART, and 10MHz clocks on the flash (at 1V due to the V01)

inþESP-ROM:esp32p4-eco2-20240710
Build:Jul 10 2024
rst:0x7 (HP_SYS_HP_WDT_RESET),boot:0x30f (SPI_FAST_FLASH_BOOT)
invalid header: 0xffff0000

The USB port on GPIO24/25 enumerates as a COM port. Attempting to flash fails due to no flash power, but it does ID the chip as V1.3 and shows a plausible MAC address.
I read out the e-fuses and compared to the device on my devboard, only obvious differences are ( my chip / devboard chip)
WAFER_VERSION_MINOR (BLOCK1) 3 / 0
And the calibration data, which is different but not vastly so

VBAT is connected to +3v3 as I don't need the RTC
Current draw from 3.3V is 62mA ( includes 1.2v reg) ( 9mA when reset is low)
If I disconnect EN_DCDC from the 1V2 regulator and set it high at the regulator, 3v3 draw reduces to 36mA and there is now 1.2V on VddHP. No change to LDO values.

1V2 DCDC is TLV62569DVBR

Chip is from JLCPCB/LCSC, marking ESP32-P4 NRW32 ( former same as the devboard I'm using) FEF0 FMDC183

I've checked every power pin with a meter, and tried two boards with the same result.

Disconnecting V03 from VDD_MIPI makes no difference to the V03 voltage
I tried with and without the 1V2 supply connected to pin 54 - no difference

Am I missing something obvious....?

**EDIT** I now realise that the EN_DCDC low is normal until boot, so looks like something to do with the LDOs - V01 for the flash at 1.1V seems likely to be a symptom of something else - isolating it from Flash Vdd and VDD_PST3 makes no difference - still sits at 1.1V

[mikeselectricstuff]

OK think I may have figured it out - I have V01..4 order reversed, so may have smoked the PSRAM - seeing if I can track-hack a new PCB to confirm.....

[mikeselectricstuff]

Yes, that was it !
I didn't realise that only the flash LDO is enabled initially, hence confusion over the other voltages.