RE: Power Management

Klok, F.H. (F.H.Klok@research.kpn.com)
Fri, 13 Jun 1997 08:38:13 +0100

>
>> As far as power management is concerned:
>> I have worked a considerable time now to enhance OmniSwp (DOS key
>> relocation and virtual 80 column screen, ) with power management. This
>> is however not a trivial exercise. It is possible to program the PMU
>> registers like Maciej did, I made this exercise too, but there is no
>> real power saving as long as you don't goto sleep or suspend mode (at
>> least I didn't manage, but maybe Maciej did, could you post this binary?
>> I guess if it's small it's OK?). Besides there's difficulty in getting
>> back from suspend, the BIOS seems to reprogram the PMU registers in a
>> way that makes the OG hang sometimes.
>
>I cannot agree with your statement.
Good, let's have some lively discussion...;-)

>The VG230 goes into DOZE mode and this
>saves power while running programs and no keyboard or screen activities take
>place. Of course more power is saved when OGO is in the sleep mode.
>I had no problems getting back from suspend mode (if this really is suspend
>mode). The power consumption is actually higher than you mention (about 7mA).
>So probably this is sleep mode.
>
>Please find below my measurememnts:
>
> DOS DOS PMU GEOS Note
>
>sleep n/a 6.8mA 1mA
>idle 88mA 88mA 70mA *1
>running1 344mA 126mA 312mA *2
>running2 344mA 344mA - *3
>running3 344mA 126mA - *4

Interesting. How did you measure? My measurements show quite different
numbers. The one we can compare is your *1. I found there 50mA, 50mA and
38mA. The figures you show are higher but show the same kind of
distribution. The same power consumption in unmanaged DOS mode and PMU
managed DOS mode. That was my whole point. I agree with you that sleep
and suspend mode save power but there should be a difference in idle DOS
mode between unmaged and PMU managed power consumption in my opinion
because the OG should go into the DOZE state. I have tested this and the
thing really goes to DOZE, but no power is saved. I think this rather
peculiar since clock speed should go down by a factor 8 in this mode. I
think however that I've found the discrepancy between Geos and DOS modes
as to powr consumption. In Geos the serial i/o is completely turned off
until it is needed, in dos mode, only clocks will be disabled of this
port. This enable of serial i/o in geos goes completely transparent so
it seems. If I disable serial i/o in DOS I get the 38 mA power
consumption.

I have to go on a business trip the next week and a few days the week
after that and won't have time either to fiddle with my OG or program
for it and will have no email access..:-((. When I get back I will try
to copy the measurements made by Maciej and see what they result in on
my machine.

Frits
>
>Notes:
>*1: DOS: command prompt
>*2: DOS: gwbasic v. 3.22 idle mode; GEOS: moving card in Solitaire
>*3: DOS: gwbasic v. 3.22 simple for-next with print
>*4: DOS: gwbasic v. 3.22 simple for-next without
>
>Best regards,
>
>Maciej Burczyk
>mabur@polbox.com
>