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

[Cormac Duffy]

No the processor can be woken up by any external interrupt (see atmega128 manual, sure its the same for msp430) therefor the cc2420 radio or similar will ususaly interrupt the processor when the packet arrives, dont know name of interupt of hand (see cc2420 manual). This will wakeup cpu from power save and jump to interrupt. BUT certain power save mode such as sleep modes will take about 4 ms to wakeup, this might not be responsive enough. If this is the case use an idle power mode to reduce power consumption. In fact TinyOS already does this im sure automatically. hope this helps Cormac On 5 Sep 2006, at 19:07, Yinying Yang wrote: 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:[EMAIL PROTECTED]]  Sent: Monday, September 04, 2006 4:00 AM To: [EMAIL PROTECTED] Cc: tinyos-help@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" <[EMAIL PROTECTED]> Subject: [Tinyos-help] The relationship between radio sleep and CPU sleep To: tinyos-help@Millennium.Berkeley.EDU Message-ID: <[EMAIL PROTECTED]> 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:            [EMAIL PROTECTED] web:     www.cs.ucc.ie/~cd5 telephone:     0872039750 ___________________________________________________ Cormac Duffy M.Sc B.Sc Computer Science Dept. University College Cork College rd. Cork Ireland email:             [EMAIL PROTECTED] web:               www.cs.ucc.ie/~cd5 mobile:          +353-87-2039750

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