Hi all,
Let me go through my scheme again, to avoid misunderstandings:
I have one acc/gyro hooked up on a Mica2Dot, that's transmitting this
20byte-packet to a TOSBase station programmed on a Mica2.
I've decreased my fire events to 3ms, but the bottleneck was around 33ms
anyway, which lead to 30packts/s. I intend to do one hop only with just one
Mica2dot.
To exactly avoid the frequency sweeping that you mentioned (because I intend
that my BaseStation listens to just ONE channel), I intended to fix the freq
and avoid that loop. This is why I was wondering that that loop took the
aforementioned 33ms.
About the Manchester Coding is Ok. I knew that it halved the bandwidth. But
still with 38.4kbps I imagined it would be fine.
Anyway, I got to the CC1000ControlM.nc (which seems is the one that implements
the receivemsg command after going really really deep) and I got this table,
where the IF is 150Khz and there are some constants defined, so as the osc
core. Is this where the channels are defined ? (there are some other "for"
loops that really use this array, but I wasn't sure about this strange numbers)
It seems they redefine frequecies, based on their desired ones.
Anyway, thanks guys.
Edgar
***************************************************************************************************
const uint32_t FRefTbl[9] = {2457600, 2106514, 1843200,
1638400, 1474560, 1340509, 1228800,
1134277, 1053257}; const uint16_t CorTbl[9] = {1213, 1416,
1618, 1820, 2022, 2224, 2427,
2629, 2831}; const uint16_t FSepTbl[9] = {0x1AA, 0x1F1,
0x238, 0x280, 0x2C7, 0x30E, 0x355,
0x39C, 0x3E3};
> From: [EMAIL PROTECTED]> To: [EMAIL PROTECTED]> CC: [EMAIL PROTECTED]; [EMAIL
> PROTECTED]; tinyos-help@millennium.berkeley.edu> Subject: RE: [Tinyos-help]
> Pumping up bandwidth - Mica2Dot/Mica2> Date: Mon, 14 Apr 2008 22:20:22 -0700>
> > I'm not sure if this applies to all mica2's, or just some older versions.>
> I'm also not sure about OEM's. You'll have to screen yours nodes yourself> to
> see if this applies. > > Our experience (and we're not alone) has been that
> there was not a good> 50-ohm impedance match on the passive network
> connecting the radio chip with> the antenna. Where there should be 50-ohm
> traces on the PCB, there is not.> This steals a few dB of output power, and
> significantly decreases range (you> double the range for every 3 dB, so even
> 3 dB less is half the range). > > Mica2Dot's are even worse: in an attempt to
> meet size specifications, the> matching network is split across two sides of
> a PCB. This is never a good> idea, because you may not be able to guarantee
> the reliability of the> radio's matching network. With the matching network
> separated, small> manufacturing differences of the PCB can cause significant
> differences in RF> response from module to module. And, mica2dot's don't have
> a sufficient> ground plane.> > Finally, the curly-q loop thing added to the
> end of the wire antennas that> come with the mica2dot's are a bad idea. This
> adds some unnecessary> horizontal polarization to the wave. A vertically
> polarized wave is much> better. Horizontal polarization gets eaten quickly by
> the ground. Straighten> out those wire antennas, and add a ground plane.> >
> -David> > > -----Original Message-----> From: Michael Schippling
> [mailto:[EMAIL PROTECTED] > Sent: Monday, April 14, 2008 8:05 PM> To: David
> Moss> Cc: 'Edgar Charry'; 'Eric Keller'; tinyos-help@millennium.berkeley.edu>
> Subject: Re: [Tinyos-help] Pumping up bandwidth - Mica2Dot/Mica2> > YOW!!!
> Another information packed post (IPP).> Maybe we could start a radio theory
> page on our new improved doc site?> But what's "that broken matching network"
> mean?> MS> > > David Moss wrote:> > Manchester encoding. And CSMA.> > > > > >
> > > Manchester halves the throughput. Instead of 76.8 kbps, Manchester will >
> > force your radio to transmit at 38.4 kbps. Getting rid of Manchester > >
> may not be a simple task: it's there to zero out the energy seen by a > >
> receiver, so it can easily know that it's receiving valid data.> > > > CSMA
> causes your transmitter to share the channel with other > > transmitters, and
> the channel checks may be spaced relatively far apart > > which dramatically
> decreases throughput.> > > > > > > > The CC1000 radio could be a really
> kick-ass radio if it were implemented > > properly. The ability to easily
> enable/disable Manchester, CSMA, etc. > > (among other things) would really
> improve its situation. The CC1000 > > radio is much more energy efficient
> than the CC2420 radio, and can > > transmit a lot farther than the CC2420
> radio (but that broken matching > > network on mica2's and especially
> mica2dot's really cause everyone > > problems). It's unfortunate so many
> people dismiss the CC1000 radio as > > obsolete, when it could really
> outperform their radios in terms of > > efficiency and range (not
> throughput).> > > > > > > > 29 bytes is only a software (and RAM) limitation.
> Increase it by doing > > a CFLAGS+=-DTOSH_DATA_LENGTH=50 or something in your
> Makefile. Removing > > unnecessary fields from the CC1000 header will
> decrease the > > header:payload ratio and increase payload throughput.> > > >
> > > > > If you're thinking about rolling your own hardware, you should really
> be > > using CC1100 or CC2500 radios for any wireless application that
> doesn't > > require 802.15.4 compatibility: > >
> http://docs.tinyos.net/index.php/CC1100/CC2500> > > > > > > > -David> > > > >
> > > > > > > > > > > > > > > > > > > >
> ------------------------------------------------------------------------> > >
> > *From:* [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] *On Behalf Of > >
> *Edgar Charry> > *Sent:* Monday, April 14, 2008 3:57 PM> > *To:* [EMAIL
> PROTECTED]; Eric Keller> > *Cc:* tinyos-help@millennium.berkeley.edu> >
> *Subject:* Re: [Tinyos-help] Pumping up bandwidth - Mica2Dot/Mica2> > > > > >
> > > Hi all,> > > > Thanks for your prompt replies. Unfortunately I that link
> didn't let me > > through.> > > > In fact I am still trying to undestand
> them, as I wasn't aware of that > > limitation of 33-50ms of the Mica2's! You
> are saying that the maximum > > bandwidth my app should require is 0-25Hz so
> that I have a nice > > reconstruction of my wave, due to HW limitations?> > I
> knew that the CC1000 has a maximum bandwidth of 76.8kbps and of course > >
> due to EEPROM readings/writings, CPU instructions, ADC's > > measurements
> etc. this number should decrease. But I wasn't expecting a > > final
> bandwidth of 30pckts/s!!! In fact, I thought there were problems > > related
> to the TOSBase.> > My app requirement need at least 100Hz (Mica2's
> transmission needed thus > > 200 pckts/s), which is necessary to track a
> complete gait cycle using > > acc and gyros with good definition.> > > > What
> is the most critical factor in the Mica2's that blow the > > transmission
> rate so bad? Does this happen with the Mica2Dot too? Data > > compression
> (sample with a higher freq, store in the RAM and then send > > the whole
> bunch of bytes) has a limitation of 29 bytes due to TinyOS, > > correct?> > >
> > Thanks guys for the good info.> > Cheers,> > Edgar Charry> > > >> Date:
> Mon, 14 Apr 2008 12:20:38 -0600> >> From: [EMAIL PROTECTED]> >> To: [EMAIL
> PROTECTED]> >> CC: tinyos-help@millennium.berkeley.edu> >> Subject: Re:
> [Tinyos-help] Pumping up bandwidth - Mica2Dot/Mica2> >>> >> Well, since
> people are quoting my second source messages, have a look> at:> >>
> http://www.etantdonnes.com/Motes/report_mica2/> >> (which seems to be down
> right now but will hopefully be back soon...).> >>> >> However my message
> speed/reliability measurements use only the standard> >> GenericComm and TOS1
> code. I think the OP was trying to fiddle timeouts> >> and backoffs to speed
> things up further. Data mining of the help list> >> should turn up some more
> useful advice in this respect.> >>> >> MS> >>> >> Eric Keller wrote:> >> >
> There is a limit to how many packets you can send with a mica2 which > > you
> are> >> > at or above. You probably want to lower your bandwidth requirements
> > > somehow.> >> > See this message:> >> > > >>
> https://www.millennium.berkeley.edu/pipermail/tinyos-help/2008-April/032464.>
> html> >> >> >> > Eric> >> >> >> >> >> > On Mon, Apr 14, 2008 at 4:59 AM,
> Edgar Charry <[EMAIL PROTECTED]> > > wrote:> >> >> Hi all,> >> >>> >> >> I am
> trying to pump my packet transmission up between a Mica2Dot and> a> >> >>
> Mica2 to at least 200Hz [pckts/s].> >> >>> >> >> I've decreased the timer
> constant to a bottleneck of 33ms (30 > > pckts/s) that> >> >> pratically
> executes a round of ADC measurements and send the packet.> >> >> Decreasing
> from this point doesn't give me more bandwidth. However,> my> >> >> packet is
> 14bytes long (the TinyOS header + just a couple of adc> >> >> measurements +
> CRC).> >> >>> >> >> I suspect that this 33ms (parsed time stamps from
> XSniffer) are > > limited to> >> >> the TOSBase.nc on the Mica2. I suspect
> that the PLL of the Mica2 is> >> >> listening through channels and is not
> locked to the transmitter's > > one. Every> >> >> loop thus should take
> 33ms.> >> >>> >> >> Actually, I haven't been through the CC1000 conf/mod
> components > > though, but> >> >> I reckon with your experience this can be
> solved easily.> >> >> Cheers,> >> >> Edgar Charry> >> >>> >> >>
> ________________________________> >> >> Explore the seven wonders of the
> world Learn more!> >> >> _______________________________________________> >>
> >> Tinyos-help mailing list> >> >> Tinyos-help@millennium.berkeley.edu> >> >>
> > > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help>
> >> >>> >> > _______________________________________________> >> > Tinyos-help
> mailing list> >> > Tinyos-help@millennium.berkeley.edu> >> >>
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help> >>>
> >> --> >> Platform: WinXP/Cygwin> >> TinyOS version: 1.x, Boomerang> >>
> Programmer: MIB510> >> Device(s): Mica2, MicaZ, Tmote> >> Sensor board:
> homebrew> >>> >> _______________________________________________> >>
> Tinyos-help mailing list> >> Tinyos-help@millennium.berkeley.edu> >>
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help> > >
> > ------------------------------------------------------------------------> >
> > > Explore the seven wonders of the world Learn more! > >
> <http://search.msn.com/results.aspx?q=7+wonders+world&mkt=en-US&form=QBRE>> >
> > > -- > Platform: WinXP/Cygwin> TinyOS version: 1.x, Boomerang> Programmer:
> MIB510> Device(s): Mica2, MicaZ, Tmote> Sensor board: homebrew> > >
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