Andy Green wrote: > You're saying that you don't think we can ever bring the CPU up at all > if you have a battery in there that is < 2.5V?
I'm not sure. My understanding of the PCF50633 manual says that, if we enable the charger, we should be fine. My experimental results don't quite agree with this. There's one catch: if the battery drops low, the internal protection circuit turns off power completely. If you tickle it a bit by supplying external power, it instantly snaps out of this mode and you get battery power again for a bit. What I don't know is if any internal processes of the battery (i.e., chemical recovery) could cause a transition as well. So far, I haven't seen this happen, but I didn't do any long-term experiments. > ~ Or all of this only happens if we disable charging from the previous > session? If we disable charging, then - according to my understanding of the documentation - we're certainly doomed, since there's no way to get power to Vsys. - Werner