ESP32-S3 WROOM-1U Brown-out reset problem and Flashing fails

[embedded.hw9]

Hi Team,

I am using ESP32-S3-WROOM-1U-N8 module. I am using UART0 to flash the module. I am able to enter into the download mode when I press & hold IO0 pin and press & release CHIP_EN pin, but I am getting following error in my Arduino IDE console

"A fatal error occurred: Failed to connect to ESP32-S3: Download mode successfully detected, but getting no sync reply: The serial TX path seems to be down"

I connected UART0 with my Laptop and found below logs:
rst:0xf (BROWNOUT_RST),boot:0x13 (DOWNLOAD(USB/UART0))
waiting for download
ESP-ROM:esp32s3-20210327
ESP-ROM:esp32s3-20210327
Build:Mar 27 2021

this message is scrolling up continously. I checked all the strapping pin GPIO's and Boot GPIO's as Follow

GPIO0 - Externally Floating and connected to tactile switch button
GPIO46 - Pulled low
GPIO45 - Pulled high
GPIO3 - Pulled low
above are default GPIO state during powering the board.

Please suggest if we use UART Serial Download mode then also do we need to pull down GPIO45 and what could be the reason for the brownout reset detector ?
What is the threshold level of brownout detector for this variant of chip part ?

Thanks in advance for help

[ESP_Sprite]

A brownout means you have an insufficient power supply, a brownout in download mode means your power supply is *really* insufficient (normally they only pop up when you start using WiFi.). What does your 3.3V power supply look like, how is it generated? Are you sure it can deliver the >=500mA the ESP32-S3 needs, as per the datasheet?

[embedded.hw9]

Hi

Thank you very much for replying. I am sure my DC-DC converter is capable enough I have used part#TPS631000DRLR from Texas Instrument and measured stable 3.3V

Also please see below snaps of my design.

Do you think increasing R/C network time delay of CHIP_PU(EN Pin) will help, with the value like 4.7uF or 10uF.

Is my above GPIO's mentioned in initial thread is properly latched with either high/low, any changes expected over there

[ESP_Sprite]

Thank you very much for replying. I am sure my DC-DC converter is capable enough I have used part#TPS631000DRLR from Texas Instrument and measured stable 3.3V

Did you also measure that on the castellated pads of the module itself? Also with a scope, so you can see even very short power dips?

Also please see below snaps of my design.

Do you think increasing R/C network time delay of CHIP_PU(EN Pin) will help, with the value like 4.7uF or 10uF.

Is my above GPIO's mentioned in initial thread is properly latched with either high/low, any changes expected over there

That design doesn't tell me much; you didn't even include the power supply. Modifying the EN RC network won't help; if that was the issue you wouldn't get *continuous* brownouts. The GPIOs also don't cause the brownouts, so I suggest you keep those out of your mind for now.

[embedded.hw9]

Hi ESP Team,

After providing proper clean supply 3.3V@1A, brown-out reset message is gone, I am not seeing that message on UART0 but instead now I am seeing below message continously

ESPESP-ROESP-ROM:esp3òESP-ROMúESP-ROÍESP-ROMúESP-ROMESP-ROMúESPESP-ROMúESP-ROMúE SP-ROMº ESP-ROM:esp32s3-20210³ESP-ROMúESP-ROM:esp3òESP-ROM:esp32s3-20210327


I am trying to get into the Download mode but am unable to do so now. Earlier during brown-out reset I was able to enter into the Download mode.
My GPIO46 is always low(during and after the power on)
GPIO0 is tied to button with external pull-up
Also I am observing certain GPIO's during the Boot-up has either high/floating state.

Can you please help resolving this issue. All the GPIO state which are critical in serial download are mentioned in above thread.

[ESP_Sprite]

Hard to say without having your hardware on hand. For some reason the ESP32 resets very early in the boot process, but it's impossible to say what just from that; it generally does not do that by itself so I'd suspect the power supply (still; in this case a disconnect on a 3.3V pin would give results like this) or the reset circuit.