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Subject: Re: Re: time to sleep?

Re: Re: time to sleep?

From: Daniel Stenberg <>
Date: Mon, 26 Aug 2002 09:39:21 +0200 (MET DST)

On Sat, 24 Aug 2002, Paul Suade wrote:

> Just a precision, you were speaking about sleep mode, it is a mistake, you
> probably speaking about standby mode. Don't use sleep mode but standby mode
> to reduce the power consumption because sleep mode shuts down all, i.e,
> peripheral controlers like timers, external interrupts would be reset, which
> is probably not what you want.

Are we talking about the same CPU here? "Hitachi SH-1 Hardware Manual r5.0"
section 19.1.1 explains the two modes "Sleep" and "Standby".

And yes, reading this again now, I still think Sleep is the mode we want to
use. Standby seems to be more troublesome to use, even if consumes far less

Again, Sleep reduces CPU power consumption by about 33% "typcial". I think
that is enough to motivate usage of it.

Standby goes down to whopping 0.1uA but is harder to awake from and plays
more tricks with clocks and I/O ports etc. But of course, if you can make
good use of the standby mode, I'll be very happy!

Daniel "Bagder" Stenberg --
Received on 2002-08-26

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