ESP32 Forum

Posted: **Sun Oct 18, 2020 11:59 am**

Hi, I soldered the Board on an esp32-pico-d4 chip, GPIO12 is pulled up to the GND, and EN and BOOT are connected to the GND via a 10 UF capacitor, and EN is also pulled up to 3.3V via a 10K resistor, when trying to flash this happens:

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esptool.py v2.8                                                                                                         
Serial port COM3
Connecting........_____....._____....._____....._____....._____....._____....._____
A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

And if you connect via the serial port at a frequency of 115200, writes:

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rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)

flash read err, 1000

ets_main.c 371 

ets Jun  8 2016 00:22:57

And if you short BOOT to GND:

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rst:0x10 (RTCWDT_RTC_RESET),boot:0x3 (DOWNLOAD_BOOT(UART0/UART1/SDIO_REI_REO_V2))

waiting for download

But the download still doesn't happen.
What could be the problem?

Posted: **Mon Nov 02, 2020 11:58 pm**

I had a similar issue on my custom board, to activate the serial load feature GPIO0 has to be low at reset. The dev kits do that with a couple of transistors and using the DSR line from the USB.
I have to take a probe,, and ground a pad on the board before hitting the system reset switch. Next spin will be slightly different.
You seem to be be getting RTC Watchdog failures rather than just a power blink reset.
I would expect a reset to give you:
rst:0x1 (POWERON_RESET),boot:0x3 (DOWNLOAD_BOOT(UART0/UART1/SDIO_REI_REO_V2))
waiting for download

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Re: esp32-pico-d4 flash error