ESP8266 Community Forum

- Wed Jun 06, 2018 3:56 am #76313 Hi, basically I have a problem with my wiring for my wifi mini ESP8266 main board and an Arduino Uno. I have tried connecting these pins:
ESP | Uno
RX -> RX
TX -> TX
G -> GND
3V3 -> 3.3V
However, the ESP refuses to work. Is there anything I'm missing? Any help is appreciated.

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- Sun Jun 10, 2018 4:29 am #76374 Does anyone have any clue? My project is quite urgent.

- Mon Jun 11, 2018 6:51 am #76393 What was that famous line again?
Oh yeah:

the modern plague: the less information they provide, the more answers they expect ...

There's, however, one thing (or actually two) that can't be right: RX -> RX and TX -> TX should be RX -> TX and TX -> RX.
If I put my ear to your ear, we can't communicate: for this you need to put your mouth to my ear and vice versa.

BTW: the image you provide depicts a WeMOS D1 mini.

And define the urgency: it looks like a text book chapter one problem, you surely can't be in an urgent position.

Assumption is the mother of all f*ckups; I should know: I've been assuming a lot.
When you're new, don't start with a separate ESP (ESP-01 to ESP-14) module.
Get yourself a proper development board: NodeMCU - WeMos D1 - WeMos (UNO form factor) - Witty Board
ESP power requirements are 3.3V±10%@350mA
The ESP8266 IS NOT 5V tolerant on ANY pin (see item 5.14 on page 25 of the FAQ)

- Mon Jun 11, 2018 8:08 am #76395

one thing (or actually two) that can't be right: RX -> RX and TX -> TX should be RX -> TX and TX -> RX.

Actually it can be right (aside from the levels). The labeling on the Arduino board is for the on board CPU. That must be held in reset. The onboard CPU will effectively be out of the circuit. The connections to the ESP8266 will be to the USB to serial converter. And the connections to that chip will be RX-TX and TX-RX.

But the Arduino board has a 5 volt signal level and the ESP8266 needs it to be 3.3 volts. The other problem is the WEMOS board already has a USB to seial converter connected to the RX and TX pins and that will cause a conflict.

Aside from wrong signal levels I think his other problems is trying to power the ESP8266 board from the Uno's 3.3 volt supply. And it does not have the current output that the ESP8266 needs.

The bigger question is, why is he using an Arduino in the first place. Doesn't the USB to serial converter on the ESP board work? Why is he not using that USB connection to the board?