[Tinyos-devel] Patches to FTSP and CC2420 for 32kHz sync and LPL functionality

[Razvan Musaloiu-E.]

Hi!

On Sun, 28 Jun 2009, Philip Levis wrote:

>
> On Jun 28, 2009, at 11:39 AM, Omprakash Gnawali wrote:
>
>> On Sat, Jun 27, 2009 at 12:27 PM, Razvan Musaloiu-E.<razvanm at cs.jhu.edu> wrote:
>>> Hi!
>>> 
>>> On Sat, 27 Jun 2009, Omprakash Gnawali wrote:
>>> 
>>>> On Sat, Jun 27, 2009 at 10:41 AM, Philip Levis<pal at cs.stanford.edu> wrote:
>>>>> 
>>>>> On Jun 26, 2009, at 6:35 PM, Razvan Musaloiu-E. wrote:
>>>>> 
>>>>>> I update the default-lpl-new branch to use a
>>>>>> SystemLowPowerListeningC instead of DefaultLplSettingsC. The new
>>>>>> interface is like this:
>>>>>> 
>>>>>> interface SystemLowPowerListening
>>>>>> {
>>>>>>       command void setLocalSleepInterval(uint16_t interval);
>>>>>>       command void setRxSleepInterval(uint16_t interval);
>>>>>>       command void setDelayAfterReceive(uint16_t interval);
>>>>>>
>>>>>>       command uint16_t getRxSleepInterval();
>>>>>>       command uint16_t getDelayAfterReceive();
>>>>>> }
>>>>>> 
>>>>>> The setX calls are used by the user application while the getX are
>>>>>> used by LplAMSenderP and DefaulLplP. One drawback of this is the
>>>>>> fact that it doesn't prevent the user from calling the setX at the
>>>>>> wrong time. :|
>>>>> 
>>>>> This looks good -- I think my one comment would be to change
>>>>> RxSleepInterval to DefaultDestinationSleepInterval. That seems clearer
>>>>> to me.
>>>>> 
>>>>> I agree on the issues with the set calls. One solution here is that
>>>>> you have an error_t return value, with can return FAIL if done at the
>>>>> wrong time (e.g., radio is on).
>>>> 
>>>> This might preclude something like NoSE which sets different sleep
>>>> intervals at different times. Here is a link:
>>>> http://www.tik.ee.ethz.ch/~beutel/pub/MWWBT2009.pdf
>>>> 
>>> 
>>> An application can still use the normal LowPowerListening interface totweek
>>> the settings for each packet. So NoSE should still be able to do its job.
>>> 
>>> My initial idea of a default lpl was to make it very easy for an application
>>> to be compiled either in lpl or non-lpl mode. My initial proposal was
>>> exactly that. This SystemLowPowerListening we end up with is more
>>> complicated and more open to interpretation and misuse.
>> 
>> Why not making it call-at-most-once type of configuration? That way if
>> there are multiple calls from multiple Booted, we would catch that by
>> looking at the error value, even when the radio is off.

I'm not aware of any way in which you can check at compile time if the 
call is made from Boot.booted or not. Even if you make one call you can 
still make at the wrong moment.

> A better solution would be to do this with wiring checks: it's a compile-time 
> error if more than one component wires to the interface.

Do you suggest that the setX and getX should be in different interfaces? I 
can make that change but, as I said above, this doesn't solve the problem.

--
Razvan ME