ESP8266 Community Forum

- Tue Mar 24, 2015 6:24 pm #12573 I'm trying to get the ESP8266 up and running without a FTDI chip, just my Arduino Uno. But it seems really difficult. What I did:

attach the ESPs VCC directly to Arduino Uno 3.3V; RX->TX; TX->RX
Result: surprisingly worked for 2 mins, however the AT commands returned ERROR sometimes. (baud rate: 9600)

attach the ESPs VCC to 3.3V 500mA power supply; RX->TX; TX->RX
Result: AT commands don't work anymore, nothing is displayed in the serial monitor, not even my input; red LED constantly on.

attach the ESPs VCC to 3.3V 500mA power supply; TX->TX; RX->RX
Result: blue LED constantly on, no response, same as before

change back RX/TX connection, experimenting with baud rate (300 - 115200)
Result: blue LED flashes on start, flashes when something is sent (no matter what the baud rate is), however still no output at all.

Suddenly, I was also getting this error while uploading:

ser_recv(): programmer is not responding

Detaching the TX connection solved the problem. Btw, I am also using a voltage divider between TX of the Arduino and RX of the ESP.

Afterwards, the blue LED was on constantly again, even though I haven't changed the wiring... (really weird)

To me it looks like the Arduino Serial monitor isn't sending anything, because I don't even see my input. However, the Arduino can output stuff, therefore I assume a connection between Arduino and PC is existing. Maybe it has to do with the connection between TX -> RX, but I see no shorts, just an ordinary voltage divider (100 Ohm and 200 Ohm resistors).

As you might see, I spent a lot of time trying to figure this out. I'm kind of stuck now, as I'm not sure what else to try. If you have any ideas, tips or advice please leave an answer.

Sorry for my English, it's not my native language. If you don't understand something, feel free to ask.

Hope you can help me!

- Tue Mar 24, 2015 9:23 pm #12578 * You need two serial ports. One for the Arduino to communicate with the Serial Monitor and one for the Arduino to communicate with the ESP. Are you doing that? With one hardware port and one software port, sometimes timings can be messed up. I suggest the AltSoftSerial library. It's much less error prone than the Arduino stock library.

* You didn't say it, but I'll assume you have all grounds connected. Yes?

* Why are you using a voltage divider if your Arduino runs at 3.3V? If it runs at 5V, yes, but not at 3.3V. And why are you using 100 ohm and 200 ohm resistors for the divider?! Those are much too stiff. Use 1K ohm and 2K ohm. Or 2K ohm and 4K ohm.

- Tue Mar 24, 2015 10:47 pm #12581 Verify that you are sending a linefeed (newline: \n) -- most terminal programs (and perhaps your Arduino code) only sends a carriage return. My ESP8266 version is 9.2.4 and it seems to require sending both (e.g., \r\n). The red led is power (should remain steady) and the blue led should flash whenever serial chars are sent.

I would suggest using a terminal program to try talking to the chip, taking the Arduino out of the loop. In a terminal program, use CTL-J to send a newline. My chip came set for a baud rate of 9600. Some have noted after flashing the firmware that the baud rate was set to something weird like 75K.