|Re: WP34S: Power consumption|
Message #3 Posted by Marcus von Cube, Germany on 6 June 2011, 7:17 a.m.,
in response to message #2 by Paul Dale
Pauli, what does BATT tell you on your device?
One of my reflashing attempts of my 30b wasn't too smart on my side. I let it sit in SAM-BA mode for an hour or so. When I came back, the batteries were down to 2.7V :-(. Power saving is essential on this type of machine. What I've learned: Two batteries should last much longer than an hour while the machine is busy (or idling in SAM-BA mode with the cable connected.) The cable itself is powered by the calculator, so don't leave it plugged in when it is not in use!
There are essentially four modes of operation in the firmware:
1) Full power, while a function is executing or a program is running.
2) Active idle, e. g. during a programmed pause or for about half a second after a key stroke. Interrupts are running in this mode for house keeping tasks.
3) Deep sleep with display on and keyboard active.
4) Off with continuous memory.
A fifth mode is possible: Make a backup with ON+STO and then pull the batteries.
Approximate power draw from the top of my head:
1) 30 mA (10 mA if battery power is low and speed reduced)
2) 0.4 mA
3) 0.15 mA
4) ? (I couldn't measure it with my equipment)
5) 0 :-)
I'd be glad to see measurements by other people more knowledgeable than me.