Hi,
I'm facing a similar problem!
My protocol requires a strict time control on when the the packets are
actually transmitted from the base station.
I have programmed by base-station-mote with the BaseStation app in
/$TOSROOT/apps/ folder.
On the PC, my java program uses a the MoteIF class to send the packets
But unfortunately, it takes randomly a value b/w 8 to 25ms for the packets
to be ultimately broadcasted thru radio.
I mean the call to
MoteIF.send(MoteIF.TOS_BCAST_ADDR, smsg);
in java takes anything b/w 8-25ms to return.
This is causing a lot of problem for me because my application requires fine
timing control
I'm okay with a delay of 20ms but is there any way to remove the randomness
of the time taken?
In other words, is it possible to do something so that there is a FIXED gap
of few ms b/w call to MoteIF.send
and the the commencement of the radio transmission of the packet at the
Base-station mote?
Regards,
Abhishek Anand
IIT Guwahati
On Mon, Jun 16, 2008 at 9:00 PM, Andrey Gursky <[EMAIL PROTECTED]>
wrote:
> Hi!
>
> Thanks Janos for your advices!
>
> I've changed the serial speed to 230400 (because of serial speed
> declarations in GNU/Linux). It works :)
> After simple test with printf() there is about 1 Kbyte/s :(
> Than I've changed printf() test application. I supply printf() a string
> with about 250 characters, then flush(). I could read about 8.5 Kbyte/s.
> It's really more than standard for IRIS 57600 Kbit/s, but it is still less
> than standard for other platforms. I've used PrintfClient to get the data.
>
> What do you think, is there a bottleneck easy to reprogram? I haven't
> tested yet how much traffic I can transmit throw ZigBee. If this will not
> more than 8.5 Kbyte/s then there is no sense to work around serial
> communication.
>
> Best regards,
> Andrey
>
>
> > Andrey:
> >
> > I think the code change you're proposing should work.
> >
> > >So atm128 doesn't have speed enough to guarantee 256 KBit/s
> > >data connection pc<->mote? If one want this, one should
> > >implement a different platform with another microcontroller?
> >
> > There's a good chance that it works. Just give it a try. BTW, I bet
> you'll never
> > be getting 250kbps worth of zigbee payload in through the radio...
> >
> > >By the way, MIB520 has also a microcontroller on board.
> > >Is USART of Mote directly connected to FTDI chip or
> > >throw this microcontroller?
> >
> > It's hooked up directly to the FTDI chip.
> >
> > >It seems to be not so easy even at the standard serial speed :(
> > Obviously, 57600bps might not be sufficient to push through all the
> incoming
> > radio traffic...
> >
> > Janos
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:
> [EMAIL PROTECTED]
> > On Behalf Of Andrey Gursky
> > Sent: Thursday, June 12, 2008 6:00 AM
> > To: tinyos-help@millennium.berkeley.edu
> > Subject: Re: [Tinyos-help] Mote-PC serial speed increasing
> >
> > Thanks Janos!
> >
> > > On the iris, the ubrr0 register is set, at initialization time, to a
> calibrated
> > > value for 57600bps. You can change the baud rate by writing this
> register.
> > >
> >
> > I've found in $TOSROOT/tos/chips/atm128 this code:
> >
> > command error_t Init.init() {
> > if (PLATFORM_BAUDRATE == 19200UL)
> > m_byte_time = 200; // 1 TMicor ~= 2.12 us, one byte = 417us ~= 200
> > else if (PLATFORM_BAUDRATE == 57600UL)
> > m_byte_time = 68; // 1 TMicor ~= 2.12 us, one byte = 138us ~= 65
> > return SUCCESS;
> > }
> >
> > I could add the line like this (or I should seek on to find ubrr0?)
> > ..
> > else if (PLATFORM_BAUDRATE == 256000UL)
> > m_byte_time = ----->15<-----; // 1 TMicor ~= 2.12 us, one byte
> > = ----->31us<----- ~= ----->15<-----
> > ..
> >
> > >
> > > This should work with a MIB520, but it is problematic with a MIB510.
> Should
> > > you have the former programming board, the bottleneck will probably be
> the
> > > interrupt load on the mote in the pc->mote direction. Note that the
> serial
> > > stack doesn't buffer outgoing packets (mote->pc), so the app must
> assume
> > > a lossy mote->pc link.
> > >
> >
> > I have MIB520 (with usb) :)
> > So atm128 doesn't have speed enough to guarantee 256 KBit/s data
> connection
> > pc<->mote? If one want this, one should implement a different platform
> > with another microcontroller?
> >
> > By the way, MIB520 has also a microcontroller on board. Is USART of Mote
> directly
> > connected to FTDI chip or throw this microcontroller?
> >
> > There is one post seems to achieve similar goal: the highest speed :)
> >
> https://www.millennium.berkeley.edu/pipermail/tinyos-help/2008-June/034218.html
> >
> > It seems to be not so easy even at the standard serial speed :(
> >
> > Could someone point me to reference where I can read about what the
> atm128x
> > has yet free to use as quick and reliable communication with PC (SPI,
> I2C)?
> > Or the best idea were to use other small design to exchange messages
> between
> > PC and ZigBee motes?
> >
> >
> >
> > >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED] [mailto:
> [EMAIL PROTECTED]
> > > On Behalf Of Andrey Gursky
> > > Sent: Tuesday, June 03, 2008 6:16 AM
> > > To: tinyos-help@millennium.berkeley.edu
> > > Subject: [Tinyos-help] Mote-PC serial speed increasing
> > >
> > > Hi tinyOS-community!
> > >
> > > It seems possible (according datasheet) to use USART of ATmega128x in
> >57600
> > > speed mode. Thus ZigBee functions of 250 Kbit/s it would be nice to
> have this
> > > speed also between basestation and PC.
> > > Does somebody know exactly, whether it would be as of some other
> reasons not
> > > possible? Or have I to alter configuration in .../chip/atm1281 to get
> this
>
> > > working?
> > >
> > >
> > > Best regards,
> > > Andrey
> > >
> > > P.S. Particularly I'm interesting in iris-motes.
> > > _______________________________________________
> > > Tinyos-help mailing list
> > > Tinyos-help@millennium.berkeley.edu
> > >
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
> > >
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