ESP32 Forum

As a followup to this topic:

viewtopic.php?f=2&t=13272

I still can't make this board boot at power up. The theory that has been suggested is that a current inrush causes the voltage to drop, interrupting the boot. Using Mongoose, it seems that the board boots with Wifi and BLE radios on.

The board is here, although there is no schematic provided:

https://www.tindie.com/products/fusion/ ... n-bus-v21/

So, can I either (1) turn those off during the boot and thrun them on when needed later, or (2) tell the ESP32 to delay boot for several milliseconds after power is applied?

This problem is really screwing up my project and any help would be GREATLY appreciated.

Thanks...

I really doubt its a current inrush issue. I have seen on a few boards now from different people who improperly use the onboard serial chip to control the reset and GPIO0.
What I would do, its take your scope or meter and make sure that GPIO0 is bulled up to 3.3v when you plug it in. If its low at power up it will be in flash mode.

Thanks very much, I'll check that today. Sadly, the board does not break out GPIO0 but I'll try to check the chip directly.

mikemoy wrote: ↑

Sun Dec 08, 2019 5:43 am

What I would do, its take your scope or meter and make sure that GPIO0 is bulled up to 3.3v when you plug it in. If its low at power up it will be in flash mode.

I applied power and I did find 3.3V at pin 25 (IO0) and also, I checked pin 12 and it seems to be pulled low.