ESP8266

Using Arduino Microcontrollers
1

Hello,

I am trying to send AT commands to a ESP 8266. But I am getting no responds. I am using the TX and RX pins of the Arduino uno. I am not even getting a “ready”.

I connect: vcc to 3.3v, GND to ground, TX to RX, RX to TX and CH_PD to 3.3v. I have also tried to connect RST to ground. But that also did not work. I also don’t now witch baud rate I should use, I have tried 115200, 57600 and 9600.

I would appreciate all help.

Thanks in advents.

2

How are you sending the commands?

3

Making sure I got the issue correct, you connected a 5V Arduino product, without level shifters, to a 3.3V ESP8266 and, you think the ESP8266 is not doing the thing. That could be a problem.

4

Idahowalker:
Making sure I got the issue correct, you connected a 5V Arduino product, without level shifters, to a 3.3V ESP8266 and, you think the ESP8266 is not doing the thing. That could be a problem.

This is not the problem. esp8266 can tolerate 5 V serial communication

5

As a note, Espressif has removed all references to the 8266 being 5V tolerant from their documentation.

6

Idahowalker:
As a note, Espressif has removed all references to the 8266 being 5V tolerant from their documentation.

Yes because it is not tolerant. But the Serial communication works. So it is not the problem of no response from AT firmware in this case.

7

You don't say which ESP8266 module, but I'm assuming ESP-01.

I'd recommend pulling the ESP-01 RST, GPIO0, and GPIO2 pins high to ensure it comes up in the operational mode. Preferably they should be tied to 3.3 V through a resistor of 1k to 10k Ohms.

To debug, try tying the Arduino (I'm assuming Uno) reset to ground. Connect the ESP-01 Rx to Uno Rx and Tx to Tx.* This will hold the Uno processor in the reset state so you can just use only USB-Serial part of the Uno to watch what is going on when the ESP-01 boots. To make the ESP-01 reboot, touch the ESP-01 RST pin to ground. With the Arduino Serial Monitor set the baud rate to 74880 which is typically used during ESP-01 boot. Normal behavior is for the ESP-01 to output some boot message and sit waiting for AT commands. If it continuously reboots (which I suspect might be your issue) you probably have a power problem.

If the ESP-01 seems to boot ok, you can then change the Serial Monitor baud rate to 9600 (or maybe 115200) and send AT commands to the ESP-01.

    • Edded to add serial connection guidance as per Juraj's post #7. :slight_smile:
8

MrMark:
To debug, try tying the Arduino (I'm assuming Uno) reset to ground. This will hold the Uno processor in the reset state so you can just use only USB-Serial part of the Uno to watch what is going on when the ESP-01 boots. To make the ESP-01 reboot, touch the ESP-01 RST pin to ground. With the Arduino Serial Monitor set the baud rate to 74880 which is typically used during ESP-01 boot. Normal behavior is for the ESP-01 to output some boot message and sit waiting for AT commands. If it continuously reboots (which I suspect might be your issue) you probably have a power problem.

this would require wiring RX to RX, TX to TX

9

If you haven't already read this then you should.

I used it to do this

And this