Breathing Red when using Electron 3.3v pin to power another module

Hi there,

I’m currently using the electron to power an Adafruit ESP8266 HUZZAH as follows:

Electron 3.3V -> ESP VBat
Electron Gnd -> ESP Gnd
Electron TX, RX -> ESP RX, TX

For some reason, when I boot my electron with these connections in place, the electron fails to run my code. Instead, sometimes it boots to breathing red, and other times it boots to breathing white. When I boot the electron with the 3.3V disconnected, however, it boots fine and runs my code, and then when I connect the 3.3V pin after my code has started running, the electron powers the ESP just fine and the two are able to communicate without issue.

Does anyone know why this is?

Some troubleshooting steps I tried:

  • Force the ESP to go into deep sleep on startup. This brings the current draw from the ESP down to less than 1mA
  • use VIN instead of 3.3V on the electron. When this is the case, the electron always boots to breathe white, and stays that way until i unplug and replug in the VIN pin

Any help would be greatly appreciate with this issue!

@armanafghani, the Huzzah may be drawing too much current on the 3V3 line. If you disconnect everything (Huzzah power, TX/RX) from the Electron, does it work as expected? If not, you have a problem with either the USB power or the Electron.

Vin on the Electron is Vusb minue a diode voltage drop (approx 4.7v). Connec the Huzzah power (only, not TX/RX) and see if the Electron boots as expected. There may be RF interference from the Huzzah.

I’m not sure what this means but test with above suggestions and report back :wink:

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