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ESP8266-03 serial not working

PostPosted: Wed Jun 07, 2017 5:06 am
by zeoos
Hello.
I recently got a few ESP8266-03 from ebay and soldered some 2.54 headers on it.
I programmed it with arduino but can't seem to make it write anything on serial.
Arduino writes the program successfully every time on the ESP but the serial monitor doesn't show anything.

My connection is as follows:
ESP8266 -->---->---> USB TTL 3.3V adapter
VCC - 3.3 Volt on USB TTL
GND - GND on USB TTL
GPIO15 - GND on USB TTL
CH_PD - 3.3 Volt on USB TTL
GPIO0 - GND on USB TTL (for programming)
RX - TX on USB TTL
TX - RX on USB TTL

Do i have to connect it some other way for normal operation? From what I've read, GPIO0 should be LOW for programming and HIGH for normal operation.
I am using 115200 baud, will try to program with different baud.

Thank you in advance.

Re: ESP8266-03 serial not working

PostPosted: Wed Jun 07, 2017 5:21 pm
by QuickFix
When you enable the serial monitor in the Arduino IDE (making sure you've selected the correct COM-port) and you reset the ESP, you should at least get some gibberish on the screen.
If not, reverse the TX and RX leads and try again.
When you do get gibberish, first try 74880 baud (the default baud-rate with the 26MHz chrystal), followed by 115200 baud, 9600 baud and other possible values (though 74880 and 115200 are the most common).

If that all doesn't work: check all connections and, above all, make sure power is a stable 3.3V with enough current to spare; don't just rely on the power supplied by the USB -> serial convertor board used.

My personal advice to all new users is to get a decent ready made development board (with preferably an ESP-12 on it) containing an on-board serial -> USB chip; they're almost all lest than $5 / €5 a piece and they make life so much easier for the beginning (and advanced) user.

When you're used to the ESP you can always strip things down to the bare minimum needed in your project.