From: Robert Tiismus Newsgroups: comp.sys.hp48 Subject: Power the HP48 uses Date: Sat, 26 Sep 1998 00:06:14 +0300 Organization: University of Tartu, Estonia Lines: 124 Message-ID: <360C05C6.CAF@physic.ut.ee> NNTP-Posting-Host: ppp2.physic.ut.ee Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: kadri.ut.ee 906757561 7799 (None) 193.40.11.69 X-Complaints-To: usenet@kadri.ut.ee X-Mailer: Mozilla 3.04Gold (Win95; I) Xref: republic.btigate.com comp.sys.hp48:16606 A long, long time ago Douglas R. Cannon wrote > I was playing around the other day and decieded that I wanted to know just >how much current the HP48 uses with different operations. Everyone is always >saying, "IR transmissions cause a great drain on the batteries..." or, >"Lots of number crunching will cause significant battery drain..." So, I >wanted to know how much. > > In the hopes that this is interesting to others, I am posting a partial >list that I have begun to compile. These are simple operations that I was >able to think of in 10 minutes or less. If anyone has ideas for other >operations that should be tested, please email me. I would like to make this >list as complete as possible. Also, any comments, or questions are readily >accepted. > >This is the current drawn from the batteries, given the operation: > > >Current | Operation | Other > ( mA ) | | >------------------------------------------------------------------------ >0.016 | HP OFF | probably not reliable >2.22 | idle | >7.0 | "normal" program execution | ( most programs ) >7.0 | Stack manipulations | >7.0 | yat 1.0 ( Tetris... ) | >6.62 | BEEP | 600 Hz >8.84 | BEEP | 8000 Hz >8.85 | BEEP | 10000 and above >7.0 | XMITRM ( IR remote controller ) | 16.0 mA briefly >< 4.6 | Clock on in status line | flucuates (2.22 - 4.6 mA) >3.6 | Command line input | idle >2.27 | Stack depth of 500 | idle >6.8 | Plotter | sin(x) >< 3.9 | Edit mode | ( 3.6 - 3.9 ) >7.2 | Edit mode when checking syntax | or moving cursor >--------| WIRE TRANSMISSIONS -------------------|------------------- >2.22 | idle, port closed | >3.22 | idle, port open! (connected) | connected to a Mac >2.52 | idle, port open ( not connected ) | >8.15 | transferring to a mac | maximum >--------| IR TRANSMISSIONS ---------------------|------------------- >2.22 | idle, port closed | >3.22 | idle, port open (wire connected) | figure this out! >2.52 | idle, port open ( wire not connected )| this one too. >7.2 | Transmitting, trying to connect | couldn't test a real trans. >15.7 | Printing ( no printer near by ) | All time high! >-------------------------------------------------------------------- >A couple of notes: > Pressing ON does not close the I/O port, but turning the HP OFF, then ON, >the port is closed. ( I guess the manual wasn't kidding when it said to >always close the port! ) > Notice the clock. The ammeter showed a lot of fluctuation, but I am guessing >that HP draws 2.22 mA as normal, then each time an interrupt is received for >the clock, it momentarily draws around 4.6 mA. >-------------------------------------------------------------------- > >So that you can try this at home... > >How it was done: > >It was rather simple, of course. I just took out one of the batteries, >connected it back in with wires, placing my ammeter in series with the >batteries. Then, nervously, I turned it on. Since it didn't explode, I was >able to make the measurements shown. I feel that the measurements are good, >since the ammeter I used has only a 250 mV maximum burden at fullscale >of 200 mA. The only measurement I need to do more accurately is when the >HP is off. Being curious, I decided to repeat the measurements to verify given values and to get ones for my configuration. I have HP48G version R upgraded to 256 Kb memory ( with low power DIP memories. Sorry, can't remember the exact type... ) and removed the original 32Kb memory chip. Below is what I got: Current | Operation | Other ( mA ) | | ---------------------------------------------------------------------------- 0 | Coma mode | 0.02 | HP Off | 10 | Light Sleep | | | 30 | Executing code from ROM | 31 | Executing code from ROM | Interrupts Disabled 23 | Executing code from ROM | Display turned off 24 | Executing code from ROM | Interrupts and Display off | | 22 | Executing code from RAM | 24 | Executing code from RAM | Interrupts Disabled 11 | Executing code from RAM | Display turned off 13 | Executing code from RAM | Interrupts and Display off | | 15 | Command line input | | | 11 | I/O open | No wire connected 13 | I/O open | With wire connected 33 | Transmitting/receiving with the wire | 50 | Printing through the IR | ---------------------------------------------------------------------------- Could not check the file transfer through the IR, but it's probably the same as with printing. As you can see, the values are significantly greater than the ones Douglas got, so I did check my Ampermeter ( an analog one, based on the galvanometer :) and it turned out that it was indeed lying, but in opposite direction, giving some 8 % smaller results. So the values above are really by some amount bigger. I would like to get some feedback on those values to verify that they are not caused by the memory chips I used for the upgrade, but by some other changes in HP48 internal architecture. Best wishes from, -- Robert Tiismus http://www.physic.ut.ee/~robert