Brown-out & hard reset

Hardware
1

Hello,

I’m using the Notecarrier-F with a Note-NBGLW.

Whenever I power up I get this sequence of events shown in Notehub:

_session.qo
{“closed”:true,“why”:“session closed because the notecard has opened a newer session”}

_geolocate.qo
{“country”:“CA”,“location”:“”,“radios”:{“wifi”:6}}

_session.qo
{“opened”:true,“why”:“first sync; continuous connection mode”}

_health.qo
{“text”:“boot (brown-out & hard reset [17281])”,“voltage”:4.6679688}

Should I be concerned about the brown-out & hard reset or is this normal? I’ve integrated this notecard on a custom PCB, and saw the same sequence. I thought it might have been a hardware issue on my PCB.

Thanks.

2

I should add that my device works like I want it to after powering up. But I’m trying to debug this brown-out issue and can’t tell what causes it. I’ve added capacitors to the VIO_P and MODEM_P pins and don’t see any voltage drops on an oscilloscope.

Thanks!

3

I’ve noticed the brown-out & hard reset only happens in hub.set mode:continuous. I’ve changed to hub.set mode to minimum and there are no more brown-out messages. Is there an explanation for this?

4

Hi @hgonz and welcome to the Blues community!

Generally speaking, if you perform a hardware restart of the Notecard within 15 minutes of having been connected, you will see this “brown-out” message. It’s important to remember with the Notecard that it was built to remain powered on and connected to a battery indefinitely as there are non-trivial usages of power and data when cold booting (and Notecard idles incredibly low at 8-18uA).

There shouldn’t be a difference between continuous and minimum modes, as again this should only appear on restarts (or if your voltage really does drop too low to support your product).

Rob