I *think* my BBB is getting powered down becauae the 7805 chip I'm
using it needs a heatsink and is thus running just a bit too hot and
protecting itslef by turning off.
Is there any way to tell if this is happening from the BBB logs? I
can't see anything obvious in syslog at all.
When it has turned off *all* the lights are off and I have to remove
the power and restore it to restart the BBB. Does this suggest the
7805 is turning itself off? (I'll check with a meter next time it
If you cut power, the processor turns off so it is hard for it to keep running and print logs without power.
Hook a meter to the DC input and see if it turns off. If it does, the 7805 is shutting down. The best that can do is 500mA without a heat sink,.
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If you cut power, the processor turns off so it is hard for it to keep
running and print logs without power.
Yes, I realise that, but I wondered if the power management chip 'saw
it coming' and did something while the capacitors discharge.
Hook a meter to the DC input and see if it turns off. If it does, the 7805
is shutting down. The best that can do is 500mA without a heat sink,.
I'm a bit tight for time (going home, leaving this BBB running on our
boat) so I've reduced the input voltage to the 7805 from raw battery
voltage which is about 14 volts down to 9 volts (which I need for
various other devices). Thus the 7805 will be dissapating much less
power now - (4 x current) watts as opposed to (9 x current) watts.
Nothing the PMIC can do once it is gone. There isn’t enough capacity in the caps t keep a board running.
9V is better than 15V.