>Also, does anyone know roughly how long a Palm III(e/x) lasts if left on
>with serial port open and backlight on? With backlight off?
I have an application which requires that the serial port be "on" at all
times because the listener-type devices used in the application don't
handshake consistently (i.e., dropped bytes after XOFF).
Confirming Dave's comments about "40 hours", my firsthand experience is
that an original Palm III will get 36-38 hours from a fresh set with serial
port always on. Running the backlight will take this down to 6-8 hours.
Same operation on a Palm V will get roughly 10 hours per full charge,
dropping to an incredulous 2 or 3 with the backlight.
Bottom line is that if your application is transmit only, turn the port on
only when you need to send characters. Like Dave said, you can probably
double battery life. HOWEVER... BIG CAVEAT... I have discovered that
opening and possibly closing the port outputs a 00h character on each
occurance. Make sure that your device can tolerate extraneous nulls.
Anyway, while I certainly haven't subjected this to the scrutiny of
scientific study ;-) , at least my observations indicate that the backlight
consumes at least four times more energy than the serial port does. This is
counter to everything I've heard here and elsewhere - that the serial port
is the bigger offender, but not by much.
Maybe someone else might know - what is the battery life with "continuous
on", without either the serial port or backlight? How about with just the
backlight? It would be interesting to verify if backlight + serial >> than
the sum of the two run separately.
...mike
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