ESP8266 Community Forum

- Thu Jan 08, 2015 4:42 pm #6724 I can't for the life of me get this little thing to work! All I'm trying to do, for a start, is to issue an AT command.

I'm using a cheap 5V->3.3V converter, and a cheap usb to serial thingy, which I'm starting to suspect is the root of my problems. However - the USB adapter driver is installed correctly, and it can communicate with "itself" as a loopback device (by shorting TX and RX).

I'm connecting the following PINs:

VCC <--> PSU 3.3V
GND <--> PSU GND
CHPD <--> power supply 3.3V
RX <--> USB RX (or TX)
TX <--> USB TX (or RX)
GPIO0 <--> power supply GND (or leave it unconnected)

The power (red) LED will come on, and with GPIO0 pulled low, the blue LED will briefly blink. It does not blink when trying to communicate over serial (any baud rate).

When nothing's connected to GPIO, the device will blink when trying to communicate with it, but I only receive garbage replies (¤
 and such) when issuing commands over serial.

I've tried with two ESP8266s, and they behave the same way.

Am I missing something obvious? Should my next step be to try a higher quality serial converter (which?), or a different computer? Any suggestions?

For reference, I've attached a picture of the hardware I'm using.

Attachments

Picture of ESP8266, Power Supply, and USB serial adapter

- Thu Jan 08, 2015 4:56 pm #6727 it's possible that modules doesn't have the at firmware on them :/

have you tried to download the at firmware ? With the GPIO0 not connected, all seems fine. Try 115200 & 9600 and if the only response you get is gibberish on startup you better download the at firmware again

- Thu Jan 08, 2015 5:36 pm #6731 A lot of us went through the same experience.
the ch_pd pin should be connected to +vcc
then before connecting the gpio0 to ground for flashing a new firware, just check that when you power on the chip you do get "someting" on the serial port. (should be at speed 115000). This will insure that your seiral communication is working.
if your device is like the one I received, it is just non functional as such unless you flash a new firmware. it is simply not responding
So connect gpio0 to ground, download the AT or LUA firmware and flash it. the situation should be much better afyerward and You will be able to talk to your device
if you flash the nodemcu firmaware, the serial speed for talking to the device after flashing is 9600bps

- Thu Jan 08, 2015 5:45 pm #6733 papagenic, is there any chance that you know the pinout for blue power led ESP-07 ?