My board wouldn't boot, why?

Posts: 8
Joined: Wed Jul 08, 2020 5:27 am

My board wouldn't boot, why?

Postby szabiaura » Thu Oct 22, 2020 4:24 am

I built a board hosting a ESP32-WROOM-32D module. After assembling, I just can't get it to do anything. Schematics are according to the datasheet. Here's what I checked:
  • pin 1 (GND) is low
  • pin 2 (3V3) is high (3.24V)
  • pin 3 (EN) is high
  • pin 14 (MTDI/GPIO12) is low
  • pin 26 (GPIO0) is low to enter download mode for flashing initial firmware
  • tried swapping TX/RX; the serial adapter works for sure
  • power supply not shorted, the board takes about 10 mA

Code: Select all

$ flash
Executing action: flash
Choosing default port b'/dev/ttyUSB0' (use '-p PORT' option to set a specific serial port)
Running ninja in directory /home/szabi/Documents/ledbridge/eclipse-workspace/8k_firmware/build
Executing "ninja flash"...
[1/4] Performing build step for 'bootloader'
ninja: no work to do.
[1/2] cd /home/szabi/esp/esp-idf/components/esptool_py && /home/szabi/.espressif/to..._firmware/build" -P /home/szabi/esp/esp-idf/components/esptool_py/run_esptool.cmake --chip esp32 -p /dev/ttyUSB0 -b 460800 --before=default_reset --after=hard_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 4MB 0x8000 partition_table/partition-table.bin 0x1000 bootloader/bootloader.bin 0x10000 LEDBridge8KFirmware.bin v3.0-dev
Serial port /dev/ttyUSB0

A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header
CMake Error at run_cmd.cmake:14 (message): failed
Call Stack (most recent call first):
  run_esptool.cmake:21 (include)

FAILED: CMakeFiles/flash 
cd /home/szabi/esp/esp-idf/components/esptool_py && /home/szabi/.espressif/tools/cmake/3.16.4/bin/cmake -D IDF_PATH="/home/szabi/esp/esp-idf" -D ESPTOOLPY="/home/szabi/.espressif/python_env/idf4.2_py3.8_env/bin/python /home/szabi/esp/esp-idf/components/esptool_py/esptool/ --chip esp32" -D ESPTOOL_ARGS="--before=default_reset --after=hard_reset write_flash @flash_args" -D WORKING_DIRECTORY="/home/szabi/Documents/ledbridge/eclipse-workspace/8k_firmware/build" -P /home/szabi/esp/esp-idf/components/esptool_py/run_esptool.cmake
ninja: build stopped: subcommand failed.
ninja failed with exit code 1
This is the second board that I assembled, the other one does the same. I appreciate any ideas what else to check.

Posts: 8
Joined: Wed Jul 08, 2020 5:27 am

Re: My board wouldn't boot, why?

Postby szabiaura » Thu Oct 22, 2020 5:52 am

The solution is to pull EN low momentarily. This boots up the board into download mode.

How to make sure the board boots up without intervention after power is applied?

Posts: 34
Joined: Sat Mar 28, 2020 4:18 pm

Re: My board wouldn't boot, why?

Postby becorey » Mon Nov 09, 2020 6:14 am

Most boards have either a physical button for EN and GPIO0, or they have an auto flash circuit using the DTR and RTS signals from the usb to serial chip

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