I am using an external battery management. I need to get a pin high within 500ms. I am running my code with SYSTEM_MODE(MANUAL) but that doesn’t really help. I made the following timing measurements:
I connect 10v to VIN.
790ms: the 3.3V pin starts outputting 3.3v. I think this is due the BQ24195 (Is there a way to disable it?).
1,5 sec: The first line of code is executed. (Maybe the bootloader?)
Electron is really designed to have a battery connected at all times. There are ways to defeat that but you are definitely swimming against the tide when you try.
Do you have a battery on your Electron? The one it shipped with or another?
I am using a 3 cell setup and an external battery management chip (BQ40z60). Also a on/off switch is included (LTC2954) therefore the 500ms time limit.