Path: utzoo!attcan!uunet!decwrl!sdd.hp.com!hplabs!hpfcso!hpfinote!rrd
From: rrd@hpfinote.HP.COM (Ray Depew x2419)
Newsgroups: comp.sys.handhelds
Subject: Re: HP 41 battery indicator?
Message-ID: <19080007@hpfinote.HP.COM>
Date: 12 Sep 90 15:10:39 GMT
References: <36930@ut-emx>
Organization: Hewlett Packard CICD
Lines: 27

>I have a question regarding an old HP calculator called the 41CX;
>doing to set up the recharge.)  Is there any way I can find out how
>much charge is left, so I can recharge it when it's low, but not
>yet to the state where it'll beep at me?

Well, I've still got my 41CX, but I gave away the manuals and Wlodek's
masterpiece a while ago, so ....   There is a "Low Battery" system flag
on the 41.  It can be tested, but not set or cleared (by normal means,
anyway).  I think (corrections, please) that one system routine monitors
the battery and sets the flag, while another routine monitors the flag
status and turns on the BAT annunciator and/or the "LOW BATTERY" message.

Unfortunately, the battery check on the 41 is a binary check:  either it's
low or it isn't.  (Comparators are not as complicated as ADC's, I guess.)
Fortunately, when the annunciator comes on you still have plenty of 
runtime before you're REALLY in trouble.

>Thanks,
>Scot

Not what you wanted to hear, but you're welcome anyway.

Regards
Ray Depew
HP Colorado IC Division 
rrd@hpfitst1.hp.com
Just me shooting off my mouth....