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By headhunter862
#55624 I am new to the ESP8266 world and a few days ago I got my ESP8266-12F. I bought it from It is just tiny chip with no USB. To connect it to my laptop I bought a FDTI232RL USB-To-Serial breakout board. Now I connected the ESP board to my laptop using the USB-To-Serial board. I connected the pins as follows

esp fdti232rl

RX -> TX
TX -> RX

Then I uploaded the example Blynk sketch for ESP8266. When I upload, I get these error:

error: Failed to open COM1
error: espcomm_open failed
error: espcomm_upload_mem failed

Can anyone help and guide me ?
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By rudy
#55671 COM1 may not be the right serial port. Do you get any lights flashing on the USB to serial converter? If not then select a different serial port.

Also you need to have specific pins set at specific logic states.


Ignore the deep sleep resistor connection. GPIO0 (burn) must be low, then do a reset and the blue light on the module should flash once. Then try loading the sketch.
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#55752 Rudy metioned the solution, the ESP8266-12F does not have any pull-up or pull-downs onboard so you have to connect every needed pin yourself to the right logic level.

PS. not sure what kind of cable you have but make sure your VCC is 3V3 and not 5V!