AVR-Chat

Yeah yeah like David said...

Look for a "dc-dc buck converter."  Check out Texas Instruments.  They
have an excellent sample policy and you can get samples right on line.
You can get more samples if you call in.

Typically, you can get 5 online or 20 (max) if you call in.  Don't abuse
the privilege please, I rely on this sampling service and would be upset
if policy changed.



-----Original Message-----
From: David VanHorn [mailto:dvanhorn@cedar.net] 
Sent: Monday, April 05, 2004 8:11 AM
Subject: Re: [AVR-Chat] sleep mode in mega16

At 07:37 AM 4/5/2004 -0700, jay marante wrote:

>im using max883 as a linear regulator. its output is about 200-250mA of
current. 

Your system draws that much?  If so, you seriously need a switcher.
The linear is wasting about 40% of the power available, and a switcher
will not be more than 10%, and could reach 2% for an ideal design.

>how will i code the power-save mode in ICCAVR?

Complicated subject.

You have to determine how to configure the I/O ports so that the
external stuff draws as little power as possible, then set the ports up
that way.

You'll also have to pay attention to sequencing as you go to sleep, and
as you wake up agian. There may be things in your externals that need to
be done in a certain order to avoid damage, or large power draw.

In the chip, it's "simply" a matter of shutting off peripherals you
aren't using, lowering clock speeds to minimum, and activating sleep.
The sleep instruction has to be preceeded by a sleep enable.

If course you also have to provide a wakeup mechanism.

It's not a simple thing.

Can you describe the system in more detail?


 
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