ESP8266 Community Forum

- Tue Nov 06, 2018 10:10 am #79038 Help!

I have a ESP-WROOM-02 connected to an ATmega1280.
I have level conversion in place.
I have managed to get the boot response from the module.
Other than by scope, I don't an have a simple method to
monitor the input and output. So I cannot (at this point) let
you know what the boot info includes.

When I send a command string to the module, it does not
respond.

The string being sent is "AT+CWMODE=3", followed by '\x0D', '\x0A'.

The module is clocked at 26Mhz and I have measured the TX and RX
baud rate at 76.8k.

I have confirmed that the RX data does arrive at the RX pin on the module.

A couple of questions:
Does anyone know whether or not parity is being used?
Does this module (ESP-WROOM-02) come with preloaded with firmware?

Newbie with this part so any suggestions would be helpful.

Regards,

A.

- Tue Nov 06, 2018 6:28 pm #79045 I don't have any experience with the ESP-WROOM-02 myself, but as far as I know it shouldn't differ much from other ESP modules, so it will boot at 74880 Baud (this is not a typo, it actually boots at 74880 Baud) and after that, when the AT firmware is loaded, it switches over to 115200 Baud.

Other than by scope, I don't an have a simple method to
monitor the input and output.

As with all serial communication, you can read along all passed data by connecting the TX and RX lines via diodes to a RX-line of a COM-port on your PC.

Above is what we used in the old DB9-RS232 days, but it can similarly be used with TTL serial.

But, I actually wonder why you (and a lot of people like you) are assuming a lot, without getting to know your newly acquired ESP.

You should first play with it by simply connecting it (also using a level convertor of course) to a serial port (via USB) on your PC and using a terminal program like PuTTY.
That way you can try out all the available AT commands (when there's actually AT firmware installed; you don't know since you haven't tested it) and see how it behaves without using a lot of assumptions (please read my signature about assuming things).

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.