ESP8266 Community Forum

Hello,
I'm using an esp-12, which I've managed to flash ok and it works immediately after flashing.

It doesn't work after that, it doesn't run the sketch. It doesn't run if I leave it fully wired for bootloading and it doesn't run with just power.

I'm using a USB FTDI which does 3.3v, I'm using that to power the device and only have VCC and ground connected (and a buzzer to gnd and 14).

I've tried with and without En pulled high. What have I missed?

The FTDI chip does not provide enough current to power the ESP8266. It provides enough power to burn Flash but once the ESP8266 boots up and turns on the WiFi radio, the ESP8266 runs out of power. ESP12 boards have voltage regulators (usually LDO) capable of supplying from 500-800 mA.

There is a lot of misleading information available about current consumption. Most of the information excludes the peak draw the ESP8266 requires.

I had tried to use very good quality 250mA rated voltage regulators and that was marginal. Sometimes I would get resets and never know why, thinking it was a code problem. After discovering that power was the problem I use 500mA regulators and have not had the problem again.

As gdsports said, the FTDI chip is incapable of powering the ESP. And it is recommended that a good LDO (low drop out) regulator be used. This is important when using the 5 volt line of a USB port, because it is quite often lower than 5 volts when it gets to your device.

cowjam wrote:[...]
I've managed to flash ok and it works immediately after flashing.
It doesn't work after that, it doesn't run the sketch.[...]

GPIOs are wired different for flashing than for running your sketch.