import network causes reboot, due to power brown-out

[rdagger]

Just installed today's firmware build: esp32-20170730-v1.9.1-391-g06168c92.bin The command import network is now causing the ESP32 to reboot. It's also causing problems with the umqtt.simple library.

[rdagger]

Here's the error message:

import network I (132277) wifi: wifi firmware version: f092575 I (132277) wifi: config NVS flash: enabled I (132277) wifi: config nano formating: disabled I (132277) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE I (132287) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE I (132307) wifi: Init dynamic tx buffer num: 32 I (132307) wifi: Init dynamic rx buffer num: 64 I (132307) wifi: wifi driver task: 3ffd91e8, prio:23, stack:4096 I (132307) wifi: Init static rx buffer num: 10 I (132317) wifi: Init dynamic rx buffer num: 0 I (132317) wifi: Init rx ampdu len mblock:7 I (132327) wifi: Init lldesc rx ampdu entry mblock:4 I (132327) wifi: wifi power manager task: 0x3ffde4d4 priautoconnect: /dev/ttyUSB0 action: remove USB Serial device '/dev/ttyUSB0' disconnected

[MrSurly]

I've had this problem before. The fact that the USB disconnected is a pretty clear sign that your power is browning out. This happens because WiFi draws considerably more current when it fires up, and if you have a high resistance on the power wires, this can happen.

Try using use a shorter USB cable (seriously).

[dpgeorge]

The latest code works for me. The ESP IDF recently changed the way it handles brown-out detection so that's further evidence it could be related to power.

[rdagger]

Thanks, you were right! I added an additional 5V power line and it's working now.

[dpgeorge]

You can try making the CPU run slower to use less power: it's a compile time option, grep for CONFIG_ESP32_DEFAULT_CPU_FREQ