ESP32 Forum

Hello,

I download firmware to ESP32 with make flash in Ubuntu, It prompts error:

A fatal error occurred: Failed to connect to ESP32: Invalid head of packet ('p')

But I use Espressif download tool, It is OK.

Anyone has same experience, Please give me some suggestion.

Thanks

Try setting the baud rate to a lower value (either by changing the "--baud" argument on the command line, or the setting in "make menuconfig").

ESP_Angus wrote:Try setting the baud rate to a lower value (either by changing the "--baud" argument on the command line, or the setting in "make menuconfig").

Thanks for your answer. But I use default baudrate 115200, It prompts the error. And I use 230400, It prompts the MD5 error like this
http://esp32.com/viewtopic.php?f=2&t=322

I have other question: Please see the attachment.
Blue - IO0
Yellow - EN. Why IO0's wave like this? It looks like that there is a big capacitor on IO0. But from schematic, there is no capacitor. I feel that It refers to the error

Thanks

What hardware did you take this capture from? If it's the board in your first post, can you please post the schematic?

ESP_Angus wrote:What hardware did you take this capture from? If it's the board in your first post, can you please post the schematic?

It's same with ESP32-DevKitC of Espressif.

Thanks

The V1 (blue PCB) DevKitC boards have a bug with the auto-reset circuit where it doesn't work reliably. You need to hold down the "Boot" button (J3, pulls down IO0) in order to reliably enter the bootloader. V2 (black PCB, "ESP32_Core_Board_V2" marked on bottom) DevKitC does not have this problem.

ESP_Angus wrote:The V1 (blue PCB) DevKitC boards have a bug with the auto-reset circuit where it doesn't work reliably. You need to hold down the "Boot" button (J3, pulls down IO0) in order to reliably enter the bootloader. V2 (black PCB, "ESP32_Core_Board_V2" marked on bottom) DevKitC does not have this problem.

Thank you very much.
Can you send me ESP32_Core_Board_V2 schematic? 1814830468@qq.com

Thanks again

Hi,

I have received an ESP32_Core_board_V2 from AdaFruit 1 week ago (also called ESP32DevC or Espressif ESP32 Development Board - Developer Edition PID: 3269 in AdaFruit shop see link https://www.adafruit.com/products/3269)

I'm using an ASUS N56VZ Laptop with 16GB RAM + Samsung 512GB SSD + Corei7-3630QM @2.4GHz + Windows7 64bits
I have created an ESP32 development environment using VirtualBox Version 5.1.6 r110634 (Qt5.5.1) with image Xubuntu 14.04.5 LTS
I can build all esp-idf example with xtensa-esp32-elf and latest esp-idf trunk
I have tested the board with stock firmware and all work fine (even if stock firmware is pretty limited with ssc commands which are not documented => "Please refer to document ssc_commands.xlsx for detail", even if I have reversed some command it is pretty limited).
The board use a 4MBytes Flash (FM25Q32 chipset) soldered on the ESP-WROOM-32 shield.
The board use a Silicon Labs CP2102 USB to Serial chipset

So then I have tried to use different command in order to have info about the ESP32 So 2nd time i try an other command i obtain error Invalid head of packet ('\x1b'): If I retry multiple time sometime it works again ...
I have tested different command and baudrate but I have always the same random error to communicate with the board
I have done lot of tests and I have about 3 fail out of 4 tests (so 1 work and 3 fail)
I never have more than 2 consecutive test working the 3rd is always a fail ...

Are you aware of this problem ?
Do you have a fix to have better / more robust communication ? (it seems to be not related to baudrate but more with a timing issue ...)
I will do some oscilloscope & logic analyzer traces to better understand what happen, but before to loose time on that I would like to know if such issue is known and maybe if there is already a fix/workaround... ?

For information when I'm using esp-idf/components/esptool_py/esptool/esptool.py on Windows7 it always fail so the best is to use VirtualBox today (and anyway I plan to do all with the VirtualBox image)

hydrabus wrote:I have done lot of tests and I have about 3 fail out of 4 tests (so 1 work and 3 fail)

If you put the board in download mode first using buttons does it ever fail?

analoglamb wrote:

aggressive and annoying advertising .jpg (30.3 KiB) Viewed 54167 times

ESP_Angus wrote:The V1 (blue PCB) DevKitC boards have a bug with the auto-reset circuit where it doesn't work reliably. You need to hold down the "Boot" button (J3, pulls down IO0) in order to reliably enter the bootloader. V2 (black PCB, "ESP32_Core_Board_V2" marked on bottom) DevKitC does not have this problem.

Thank you very much.
Can you send me ESP32_Core_Board_V2 schematic? 1814830468@qq.com

Thanks again

hi
please guy, Your advertising is very aggressive and annoying.
hope you understand my posting very well meaned.

best wishes
rudi