Hello, everyone,
According to Philipp Levis´s lecture, one task needs about 80 cycles
(10 micro sec). When I tested the Octav Chipara´s code of TestPureTdma in
Tinyos-2.x-contrib/wustl/upma/apps/tests in Tinyos 2.02 over Micaz, and
found each AMSend Task (message length=2 * sizeof(uint8_t)) costs about
190 ticks ( in 32kHz Timer) , which equals about 6 milliseond. This value is
not good if we use the TDMA protocol. Does anyone can decrease it or have a
better result?
Thanks a lot!
Johnson
- inyos <http://tinyos.cvs.sourceforge.net/viewvc/tinyos/>
-
tinyos-2.x-contrib<http://tinyos.cvs.sourceforge.net/viewvc/tinyos/tinyos-2.x-contrib/>
-
wustl<http://tinyos.cvs.sourceforge.net/viewvc/tinyos/tinyos-2.x-contrib/wustl/>
-
upma<http://tinyos.cvs.sourceforge.net/viewvc/tinyos/tinyos-2.x-contrib/wustl/upma/>
-
apps<http://tinyos.cvs.sourceforge.net/viewvc/tinyos/tinyos-2.x-contrib/wustl/upma/apps/>
-
tests<http://tinyos.cvs.sourceforge.net/viewvc/tinyos/tinyos-2.x-contrib/wustl/upma/apps/tests/>
-
TestPureTdma<http://tinyos.cvs.sourceforge.net/viewvc/tinyos/tinyos-2.x-contrib/wustl/upma/apps/tests/TestPureTdma/>
-
SendingC.nc<http://tinyos.cvs.sourceforge.net/viewvc/tinyos/tinyos-2.x-contrib/wustl/upma/apps/tests/TestPureTdma/SendingC.nc?view=log>
Octav Chipara
needs 80
> cycles (10 micro sec).
Mon, 16 Jun 2008 10:11:23 -0700
On Jun 15, 2008, at 11:49 PM, Tiny User wrote:
>
> Hello all,
>
> In a lecture for Philipp Levis at Stanford university
> (http://www.youtube.com/watch?v=j6hRsue5b30
> ) he said that the time to post and run a task in tinyos needs 80
> cycles (10 micro sec). please any one knows how we can calculate or
> measure these times?
There are two ways. The first is to read a counter register before and
after a post() and in the scheduler loop for a null task, and add
these two numbers. The other is to run an application with no
interrupts (no radio, no timers) that just runs a self-posting task
many times (through an increment variable). Have it send a byte to the
UART when it starts and when it ends, and record the time between the
bytes on a PC. If you run the task enough times (i.e., it takes
several seconds), the error caused by jitter on the PC will be
negligible.
Phil
_______________________________________________
Tinyos-help mailing list
[email protected]
https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
