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User avatar
By rwb
#76425 Hi,

Been trying to get an ESP8266 working with my Arduino Nano for weeks, but I think I bust it already.

To start with I wired CH_PD, RST, VCC to an external 3.3V supply, GND to GND, and RX directly to the Arduino's RX and TX to TX. (I understand that the ESP8266 RX and TX are 5V tolerant.)

With the terminal monitor set to 11500 baud I could sent AT commands.

The next step was to use software serial to send AT commands and print the response to the terminal.
However, 11500 is too fast for software serial so I sent
> AT+IPR=9600
and my simple setup sending AT commands continued to work, now at 9600 baud.

I had
> AT+IPR=9600
in my setup() for a while before I read that the board doesn't reset to 11500 when power cycled, and I was trying to get it to work with software serial.

Then it all stopped working, not even the simple setup I started with.

The blue TX LED on the ESP8266 comes on solid.

Have I bust it?
What did I do wrong?
Can it be fixed or is it junk?

Related: viewtopic.php?f=160&t=16787

User avatar
By QuickFix
#76436 Good chance you broke your ESP; it actually isn't 5V tolerant on any pin: TX and RX are just "Normal" GPIO's with their primary function (function 0) set to act as UART:
If I'm not mistaken, the blue LED on (most) boards is connected to TX (AKA GPIO1) and when UART-data is sent by the ESP, the blue LED should blink.

When it stays lit, it means it's either pulled low in firmware (at runtime) or externally (in hardware) or the port is defective.
Once you can't use TX, you won't be able to reflash the firmware, since for that to function, you'll need to have both RX as TX.

And please do yourself a favour and get yourself a development board: it just makes your own life a lot easier when you're starting with ESP's (see my signature).

Even people (with loads of experience) that create ESP-based designs for a living, first use a development board to test and debug their firmware.
Development boards are very cheap ($3 - $10), so there's no gain in not using them.
Last edited by QuickFix on Thu Jun 14, 2018 6:36 am, edited 2 times in total.
User avatar
By rwb
#76437 This claims that the IO pins are 5V tolerant ... e-Upgrade/
However, this is not mentioned in the data sheet.

There is 1 red LED for power, 1 blue for RX, and one blue for TX.

Indeed, the blue TX light goes off if I connect TX to 3.3V.