ESP8266 Community Forum

- Tue Jan 20, 2015 6:25 pm #7822 My English is not the best (especially when written fast, between small breaks), but I don't get what you're trying to say.

Well, I just wanted to say that with my old diecemilia (freeduino) it WORKS as expected, and is uploading random values to thingspeak right now.

Now I'm trying to find out WHY my arduino nano v4 and sparkfun's pro micro don't work with ESP-01 or ESP-03

- Wed Jan 21, 2015 2:27 am #7838 Sorry, my inglish is not so good too )
So lets continue.

At first please check the voltage on the Rx line. I am still not sure that tx-tx and rx-rx is the proper connection for this arduino board. If it is not 5V on Rx line - then try to swap them.
Second point is to connect the UART-USB adapter (5V version in your case) to your board. It is enough to connect the Rx line of the adapter to one of the lines Rx or Tx of your board. This will allow you to see via terminal if the data are transmitted correctly from arduino to ESP and from ESP to arduino.
It will show on which side the problem is.

- Wed Jan 21, 2015 5:14 am #7852 Thank you for your help.

I did all those scenarios - with good results - using USB-to-TTL to arduino ou USB-to-TTL to ESP boards. Only ESP to arduino (nano or pro micro) doesn't seem to work together... I might have done something wrong but after so many tries I think it should have worked. So, I have no ideia why it doesn't work with nano and pro micro...

In fact, I'm using tx-to-tx between arduino (freeduino/diecimila) and ESP - if i remember correctly i think the boards come with 'inverted' label/naming on those PINs.

- Sun Feb 14, 2016 7:03 am #41100 Did you have any luck solving this ? I have a pro micro and i am facing the same problem. TTL->ESP works fine.
I measured the volts and got 4.8v on both RX ant TX pins on the arduino, but the TTL has only 3.7 vaults.
I am starting to thing its a voltage problem.