ESP8266 Community Forum

- Thu May 04, 2017 5:57 am #65540 While uploading sketch on ESP-01, I have digitalWrite(0,HIGH) in setup(){}. Sketch got uploaded succesfully. But now I am not able to upload new sketch to ESP. There is always SYNC error.

I think keeping GPIO0 HIGH in setup has created the problem. because of which I am not able to upload new sketch to ESP.
Is there any way to rectify this error. Any guidance will be really appreciated as Right now I am not able to use ESP-01 for anything

- Fri May 05, 2017 8:28 pm #65628 As far as I know, GPIO0 should be physically (logically?) pulled low when programming it.. and 'ALSO', reset should be toggled low then high prior to 'ANY' programming. I've had to go through all the steps of re-burning the AT command set back, after my 1st attempt at the blink sketch (toggles the blue LED of the -01 on/off), so it's a good idea to have the generic ESP8266 Firmware burner, and the AI-Thinker V0.9.5.0 (9600-baud) and 0.9.5.2 (115200-baud) versions handy to replace after.. (to location 0x00000)
Hope this helps.. Also, NEVER rely on the Arduino's 3.3V supply!! the output is too weak (mA wise) to power the ESP8266 itself, let along the flash-RAM. Always have a minimum 500mA (0.5A) 3.3 supply powering the project. (I'm flirting with fire.. I run mine off a 23A (as in 23,000mA!) Converted ATX supply. one short circuit could fry things! But plenty of supply push if it needs it.)