[Tinyos-help] RE: The relationship between radio sleep and CPU

[Yinying Yang]

Thanks.
My understanding: The receipt of a message from radio can not wake up the
CPU from power-save state. But when CPU is in power-save mode, radio can't
forward a message. So if I would like to forward a received message to other
motes, I should set a timer to wake up the CPU periodically to check whether
there is a buffered message. If there is, forward it.
Is it right?

-----Original Message-----
From: Cormac Duffy [mailto:c.duffy at cs.ucc.ie] 
Sent: Monday, September 04, 2006 4:00 AM
To: yyyfau at gmail.com
Cc: tinyos-help at Millennium.Berkeley.EDU
Subject: Re: The relationship between radio sleep and CPU


No the radio can operate independently, at least on most platforms,
therefor its usually important to have a coordinated duty cycle, between
the processor
and the radio.

Also it is possible to have the processor in a low-power (sleep or idle
state) and get the radio to interrupt, (there by waking up the
processor,) when it senses packets on the radio channel, ie with carrier
sense. Obviously the radio can buffer a packet until the processor wakes
up and the
processor can then process packet. I am unsure if in tinyos the radio
drivers use a boradcast address and determine the the receipient after
packet downloaded from radio, OR weather the radio determines who is the
receipent of the packet. Obviously the later would be better, because it
means the radio wouldnt wake up the processor to see who the packets for.

I don't specialize in MAC protocols.
Hope that was a help
Cormac

On 3 Sep 2006, at 20:02, Yinying Yang wrote:

Message: 1
Date: Sat, 2 Sep 2006 21:05:33 -0400
From: "Yinying Yang" <yyyfau at gmail.com>
Subject: [Tinyos-help] The relationship between radio sleep and CPU
	sleep
To: tinyos-help at Millennium.Berkeley.EDU
Message-ID:
	<90bc03d20609021805v5e2e4b24k15c674c172d4ffe6 at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

HI,

When we put the mote into CPU sleep (power save) mode, would the radio be in
sleep mode too?
Or it is possible when we put the mote into CPU sleep mode, while the mote
can still send and receive messages?

Thanks.


-- 
Cormac Duffy     B.Sc, M.Sc
Computer Science Dept.
University College Cork,
College Rd.,
Cork,
Ireland.

email:            c.duffy at cs.ucc.ie
web:		     www.cs.ucc.ie/~cd5
telephone:     0872039750