Power Management on Saturn CPU based calculators
Normally whe distinguish between 4 modes, but most of the power consumpting units can be separately switched on or off.
1) Running Operation
The calculator is doing normal operation at nominal crystal speed, the CPU decodes opcodes, display is on, timers are on, 1ms keyboard scanning on and the Clarke/Yorke chip the card detection updating every 122uS.
2) Idle State
This is the state where the calculator is on and is waiting for input. In this case the Saturn CPU is powered down by the SHUTDN opcode, display is on, the timers are on, 1ms keyboard scanning is on and on the Clarke/Yorke chip the card detection updating every 122uS.
3) Light Sleep
This is the standard off mode. In this case the Saturn CPU is powered down by the SHUTDN opcode, display is off, the timers are on, 1ms keyboard scanning is off and on the Clarke/Yorke chip the card detection updating every 1mS.
4) Deep Sleep (aka Coma mode or storage mode)
In this case the Saturn CPU is powered down by the SHUTDN opcode, display is off, the timers are off, 1ms keyboard scanning is off and on the Clarke/Yorke chip the card detection is off.
Enter HP28S/HP48 Coma/Storage Mode
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High End Pioneers: <ON> <+> <SK6>
HP28S: <ON> <ENTER> <<->
HP48SX/GX: <ON> <SPC>
Beware that the HP28S has a bug in the hardware design around the Lewis chip, so the calculator is consuming more power in coma mode than in light sleep mode.
Here's an extract of
Path: lth.se!sunic!uupsi!rpi!dali.cs.montana.edu!uakari.primate.wisc.edu!sdd.hp.com!caen!uflorida!haven!umbc3!gmuvax2!peraino
From: peraino@gmuvax2.gmu.edu (Bob Peraino)
Newsgroups: comp.sys.handhelds
Subject: HP28 power study
Message-ID: <3017@gmuvax2.gmu.edu>
Date: 30 Nov 90 21:59:50 GMT
Organization: George Mason Univ., Fairfax, Va.
Lines: 290
Power Consumption Statistics for the HP-28 Scientific Calculator
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Robert Peraino
Scott Hutchinson
January 18, 1990
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...
Standard Modes
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Off - 13.5 uAMPS
"Storage mode"- 106.2
On/idle - 446.0
On/running - 2412.0
Christoph