On 5/9/06, shiyuan zhang <[EMAIL PROTECTED]> wrote:
Thank you for quick response.
(1) For RSSI, what's the meaning of the value? From Trawler, it seems to me
that larger means worse quality.
From my understanding, radio's sensitivity decides whether it can receive a
packet or not. Hence, should there be a threshold or range to determine
good link quality through RSSI?
Oh. Trawler is not using raw RSSI or LQI values. In Trawler, higher
means worse. You could look in moteiv/tos/lib/MultiHopLQI for the
precise function. If you are still curious to learn more about RSSI
and LQI values in particular, I'd recommend you read the CC2420
Datasheet.
(2) For TOSH_DATA_LENGTH, is it constrained by TinyOS or by 802.15.4
standard? I assume the Moteiv distribution is using 802.15.4 as default MAC
(correct me if wrong).
By the way, for education purpose, can I set TOSH_DATA_LENGTH larger than
128 bytes? what reason if not?
For a large TinyOS message (say TOSH_DATA_LENGTH=128), will the MAC layer
actually split it into smaller frames??
Tmote uses the CC2420, which is an 802.15.4 compliant radio. The
maximum message length in 802.15.4 is 128 bytes. The CC2420 hardware
FIFO buffer is 128 bytes. No messages are automatically split by
TinyOS routing. Tmote uses the 802.15.4 packet format, but not the
802.15.4 MAC protocol.
(3) How to monitor the residual energy in the battery? Is it through
monitoring the voltage? If so, how to do in TinyOS?
Yes. Use the component VoltageC.
(4) How to make Delta work with TOSSIM? Do I only need add a pc.target file
in /opt/moteiv/tools/make? If not, what's the exact reason why it does not
work?Thanks.
No, Delta is not supported in TOSSIM. TOSSIM is basically another
platform, and Delta has not been ported to it.
Cory
On 5/9/06, Cory Sharp <[EMAIL PROTECTED]> wrote:
> Hi Shiyuan,
>
> On 5/9/06, shiyuan zhang <[EMAIL PROTECTED] > wrote:
> > I am new to TinyOS, and have serveral questions regarding new Moteiv
> > distribution, LQI, TOSH_DATA_LENGTH and UART0:
> >
> > (1) What's the difference between the following three directory:
> > (a) /opt/moteiv/tinyos-1.x/tos
> > (b) /opt/moteiv/tos
> > (c) /opt/tinyos-1.x/tos
> > Especially, for those file with same name, are they all same? This cause
big
> > confusion for me.
>
> Files that exist in each of those directories are not necessarily the
> same. (a) /opt/moteiv/tinyos-1.x/tos is a particular snapshot of
> TinyOS 1.x used by Moteiv Boomerang. There are no custom
> modifications to files in that directory, everything you find in there
> you can find in CVS on its checkout date. (b) /opt/moteiv/tos
> contains code written or modified by Moteiv. (c) /opt/tinyos-1.x/tos
> is not used by Moteiv Boomerang.
>
> > For instance, for CC2420Radio part, I notice tmote.target and
> > /opt/moteiv/tools/java/com/moteiv/trawler
> > use both
> > INCLUDES += -I$(MOTEIV_DIR)/tos/lib/CC2420Radio
> > INCLUDES += -I$(TOSDIR)/lib/CC2420Radio
> > I tried "make tmote fileset" in Delta - also contain reference to 2 or 3
> > directories ...
> > Then, when we write "component CC2420RadioC", how can I know which
component
> > CCs2420Radio it will refer to (in case I want to modify)?
>
> The include directives (-I's) specify the search order. The first
> file found is used, so earlier specifications take precedence.
>
> > (2) What range of LQI would mean good link quality? I want to adjust
> > transmission power according to LQI.
> > And what range of RSSI would mean good link quality? Which one is more
> > accurate?
>
> LQI is a better indicator of link quality (hence the name "Link
> Quality Indicator") than RSSI ("Radio Signal Strength Indicator").
> You should test these values in you application to determine good
> thresholds that are suitable.
>
> > (3) Does moteiv's distrubution allow the TOSH_DATA_LENGTH be at most
(128 -
> > 10 - 2) bytes, without other modifications?
> > Can someone confirm it? I was told it can be at most 29 bytes.
>
> I don't recall testing 128-10-2 bytes, but we have tested definitely
> tested values around 40 to 60 bytes.
>
> > (4) I am new to TinyOS. Where can I find an example code to read
external
> > sensor data through UART[0] or I2C[0] and so on?
>
> http://www.moteiv.com/community/Boomerang_UART0_Sample
>
> Best,
> Cory
>
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