ESP8266 Community Forum

- Mon Apr 27, 2020 9:48 am #86780 Hi.
I'm trying something really simple which is uploading a sketch to one of my ESP12e. 

I was able to do it without a problem until a few weeks ago. Now, I receive the following message:

Code: Select allesptool.py v2.8
Serial port COM3
Connecting........_____....._____....._____....._____....._____....._____.....____Traceback (most recent call last):
  File "\Arduino15\packages\esp8266\hardware\esp8266\2.6.2/tools/upload.py", line 65, in <module>
    esptool.main(cmdline)
  File "/Arduino15/packages/esp8266/hardware/esp8266/2.6.2/tools/esptool\esptool.py", line 2890, in main
    esp.connect(args.before)
  File "/Arduino15/packages/esp8266/hardware/esp8266/2.6.2/tools/esptool\esptool.py", line 483, in connect
    raise FatalError('Failed to connect to %s: %s' % (self.CHIP_NAME, last_error))
esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header
_
the selected serial port _
 does not exist or your board is not connected

The board is connected to a CH340 USB-Serial converter, similar to this https://www.electrodragon.com/product/usb-ttl-serial-ch340-board/

Connection schematics are shown below. 


The board sends some basic info back through the serial port, so I assume serial communications work. 

I tried with a PL-2303 but it does not work anymore on Win10 (v1909) 

I also tried with ESP Flasher from ESPhome.io (https://github.com/esphome/esphome-flasher). Same results... 

Any guidance/help will be much appreciated.

- Mon Apr 27, 2020 10:11 am #86783 GPIO15 must be pulled down to 0V preferably through a resistor e.g. 4k7 for it to boot up sensibly.
GPIO00 must be temporarily pulled down to 0V during power up or reset in order for it to enter serial upload mode. When reset with GPIO00 high (default through an internal pull up) then the board will start running whatever code has been uploaded.

- Mon Apr 27, 2020 12:59 pm #86786 I have just started with the ESP-12F as well and am also finding it hard work. I found this page helpful: https://riktronics.wordpress.com/2017/1 ... explained/
If you have your serial speed at 74880 you can see the startup output.

Currently I am using (1,6) which allows UART upload and communication but fails on restart. I had a schoolboy error moment and connected to the wrong wire on the TTL lead so the problem was not the pin pullup/down after re soldeing the 10K resistors numerous times!!!!
I might put jumpers on the pins to make life easier as I am not sure if I need the same settings for UART or when it is updated by the web interface.

- Mon Apr 27, 2020 3:23 pm #86787

GPIO15 must be pulled down to 0V preferably through a resistor e.g. 4k7 for it to boot up sensibly.
GPIO00 must be temporarily pulled down to 0V during power up or reset in order for it to enter serial upload mode. When reset with GPIO00 high (default through an internal pull up) then the board will start running whatever code has been uploaded.

So btidy all I need is a 4k7 resistor on GPIO15 ( currently I have a 10K ) and can leave GPIO0 and GPIO2 unconnected? Or do I still need to do something with them for the UART connection?