WiFi.begin() reboots if microUSB not powered?

[davepl]

I have a circuit built around a Hiletgo ESP32 dev board, and everything works great when it's plugged into usb - not even a computer, just powered via a brick.

But, if I power it via the VIN from a benchtop supply, it reboots in WiFi.begin(). I can't tell if its the wdt or what's causing it, all I know is it goes into WiFi.begin() and reboots!

I've got 5V going to VIN and both GND pins grounded, and have tried supplying 3.3v to the 3V3 pin (which of course didn't help).

Any ideas?

Thanks!

[kolban]

By any chance is your power supply setup to a constant current mode? My loose thinking is that when you perform a WiFi begin, it may power on the radio which would increase the current draw. If your power supply were monitoring current consumption it might be configured to supply only a constant current ... perhaps as sensed before attempting to power on the radio.

[davepl]

Great thought... it does have a current adjustment, but I've got it set to full. I'll try it with a different power supply of some kind.

Looking at the schematic, I can't spot anything special about the circuit, presuming EXT_5V is the VIN pin:

https://dl.espressif.com/dl/schematics/ ... V2_sch.pdf

[davepl]

No luck, tried a big power brick, no luck! Still crashes in WiFi.begin() when the USB isn't powered...