Hello! I'm new into using the esp8266 wifi module. I connected the tx of esp to rx of arduino and rx of esp to tx of arduino. Connected the vcc to 3.3v, gnd to gnd, cp_hd to 3.3v, reset to 3.3v. But when i run the serial monitor, i cant seen anything on it. I tried the AT command but nothing happens. Tried also changin the baud rate but no luck. Please someone help me. Thanks!!!
If you want to use the ESP with the Serial Monitor, you have to connect TX of the ESP to RX of the USB-to-Serial converter. This is pin 1 or TX of the Arduino. (Similarly, connect RX of the ESP to RX of the Arduino.)
Also make sure that you have the line ending set to CR and LF.
It's not a good idea to use the Arduino's 3.3V output, the ESP draws too much current during wireless transmissions. Use pull-ups for CH_PD and RST. Some people claim that the ESP8266 is 5V-tolerant, but the datasheet isn't very clear. So it would be wise to add a 2k resistor between the ESP's RX and ground, to create a voltage divider with the built-in 1k resistor on the UNO.
If the Arduino is a 5V version, the 3.3V Tx high levels of the ESP8266
are may be too low for the Arduino to detect. Put a level shifter in between.
ESP8266 is not designed to be 5V tolerant afaik, though it indeed may work without destroying the device.
3.3V from ESP8266 to Arduino is fine.
OK, edited the answer. The thing is, 66% of Vcc (assuming the ESP really puts the full 3.3V on the Tx line) is not guaranteed to be read as HIGH in all situations, and may very well be the cause of breakdown in communication.
wvmarle: OK, edited the answer. The thing is, 66% of Vcc (assuming the ESP really puts the full 3.3V on the Tx line) is not guaranteed to be read as HIGH in all situations, and may very well be the cause of breakdown in communication.
Except that it's guaranteed to read a HIGH at 3.0V on a 5V board, per the datasheet.