Re: [Contiki-developers] Tmote sky low-power modes

[Jonathan L. <jo...@cs...>]

Hi Bjorn,

Thanks again for your emails re low-power modes on the M25P80.

I tried out the code you sent me for putting the M25P80 in and out of deep sleep mode and have measured the current being used, with and without deep sleep being invoked. 

Hooking the mote up to my scope reveals that it only appears to save in the μA range, if at all (it's hard to detect such small changes with my current scope-probe-resistor combination). I still get around 1.6mA being consumed even though there isn't anything to do. 

After looking at the M25P80 manual I suspect your code is doing what it is supposed to and the change in current use is merely very small. As far as I can tell from the manual, with the chip-select driven high (happens at xmem_init and after spi_flash_disable) the chip will go into stand-by mode when there is nothing to do. Assuming the M25P80 is going into stand-by mode then the change in current use between standby mode and deep sleep mode is only around 40μA, which is roughly what I am seeing. 

So probably everything is working and thank you very much again.



Unfortunately there is still something else running on the board that is using up 1.6 mA when there ain't sod all for the board to do.

My hunt for the guilty power drainer will continue and I'll let you know if I manage to achieve low μA current use for the TMoteSky board.

Purely, out of interest, if it were possible to turn the chip off completely, would the line look something like   P4OUT &= ~BV(FLASH_PWR); ? I merely ask, as I may want to do this for other chips on the board.

Cheers

	Jon







> -----Original Message-----
> From: Bjorn Gronvall [mailto:bg...@si...] 
> Sent: 06 October 2008 17:07
> To: Jonathan Lewis
> Cc: bg...@si...
> Subject: Re: [Contiki-developers] Tmote sky low-power modes
> 
> On Fri, 3 Oct 2008 16:56:19 +0100
> "Jonathan Lewis" <jo...@cs...> wrote:
> 
> Please let me know if you make any progress with putting the 
> chip into deep power down mode and waking it up.
> 
> There is a manual
> www.numonyx.com/Documents/Datasheets/M25P80.pdf
> and on pages 33-35 there is some info on this.
> 
> Cheers,
> /b
> 
> --
>   _     _                                           ,_______________.
> Bjorn Gronvall (Björn Grönvall)                    /_______________/|
> Swedish Institute of Computer Science              |               ||
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