ESP8266 Community Forum

- Fri Jun 19, 2015 3:24 pm #20963 hi everybody,

I'm trying to use the ESP-ADC DIL18 Modul (based on the ESP8266EX) together with the DHT22.

I've implemented the firmware with the latest Arduino IDE V1.6.4 for the ESP8266 (from https://github.com/esp8266/Arduino) and now the upload fails all the time with the following error message:
warning: espcomm_sync failed
error: espcomm_open failed

the ESP-ADC is connected with 3x 1,5AA batteries and the voltage is regulated via the LD1117AV33 to 3,3V. I have also used the 9V batteries or the 5v output from my USB2TTL-converter (with CP2102), but nothing happend.

The ESP modul is currently connected as follows to upload the software:

USB/TTL <-> ESP-ADC
TxD <-> RxD
RxD <-> TxD
RST <-> RST
DTR <-> GPIO 0

Battery <-> ESP-ADC
3.3V <-> VCC
3.3V <-> CHP
GND <-> GND
GND <-> GPIO 15

Does someone know, why the modul isn't booting? or can some tell me, how I can check that the module is booting correctly?

any help highly appreciated!

best regards
Joerg Weiss

- Fri Jun 19, 2015 3:45 pm #20965
I presume it is the board above ?

In your connections description, I don't see how you've connected the GPIO2, it must be pulled-up to VCC.
(see ESP boot process : https://github.com/esp8266/esp8266-wiki ... ot-Process)
Also, in case your USB2TTL (or upload software) doesn't handle properly the DTR signal, maybe you should manually pulldown the GPIO0 for programming, and leave it pulled-up for executing.

- Sat Jun 20, 2015 8:41 am #21020 yes, this is the correct board.

On GPIO2 is currently the DHT22 connected, but I'll change it, test your recommendation and give feedback .

regards

- Sun Jun 21, 2015 12:50 pm #21118 so, I've tested your recommendation, but withou success. I'll still getting the same error:
warning: espcomm_sync failed
error: espcomm_open failed

the following connection description has been used for programming:
USB/TTL <-> ESP-ADC
TxD <-> RxD
RxD <-> TxD

Battery <-> ESP-ADC
3.3V <-> VCC
3.3V <-> CHP
3.3V <-> GPIO 2
GND <-> GND
GND <-> GPIO 15
GND <-> GPIO 0

I also tested just the boot functionality (because the board should be delivered with 0.9.2, but it isn't repsonding to AT commands):
USB/TTL <-> ESP-ADC
TxD <-> RxD
RxD <-> TxD

Battery <-> ESP-ADC
3.3V <-> VCC
3.3V <-> CHP
3.3V <-> GPIO 2
GND <-> GND
GND <-> GPIO 15
3.3V <-> GPIO 0

both scenarios were tested with the 3x AA 1,5V batteries and the 5V from the USB2TTL.

any more ideas?

regards