I have a Boron that I have been testing. Today it was not connecting to the cell network, just kept flashing green.
I pressed the reset button and the LED just turned off and now its completley dead.
No matter how I power it up (USB, Battery, power to VBUS pin) there is no life on the LED or USB connection to the PC. The Charge light does come on however, but its just on constantly, even when a battery is plugged in.
When powered by USB I can measure 4.7V at the VBUS pin, but the EN pin only has 2.38V.
Does this mean the XC8107 or XC9258A has died? Or I guess it could be the BQ24195 as well.
I do not understand how simply pressing the reset button could have damaged the device.
What is 3.3V when powered by USB? Is it 2.38V? I would expect that if EN is that voltage since there's a 100K hardware pull-up on EN to 3V3. That would indicate the 3.3V regulator failed.
Also check the RST pin. It should be 3.3V.
Pressing the reset button is probably a coincidence.
The reset pin is at 500mv.
On my other Borons, the EN pin is at 3.5V
The only different with this one was the connected lipo battery was quite low on charge. But the battery chraging is before the 3.3V regulator so I doubt this had an affect.
Seems like the 3.3V regulator failed. It's uncommon, but could occur.
Like you said, it could be the bq24195 if VSYS isn't powered correctly, but that's even less common. On the Boron it's not easy to probe the voltage on VSYS, and it doesn't really matter because both are not practical to replace.