Dear Lars,

On Mon, May 11, 2009 at 2:01 PM, Lars Schor <[email protected]> wrote:
> Dear Miklos,
>
> Sorry for the late reply, but I wanted to discuss the subject first with the
> guys who wrote the platform files of the meshbean900.
>
>> Would be nice to know what ack timeout you need for communication
>> between regular nodes.
>
> We need around 2550 microseconds. So it is not much better than using the
> basestation.

Interesting. On the IRIS the SPI is set to high speed, which if I know
correctlz takes 2 cpu ticks per bit, which is 16 ticks per byte, which
is 2 microsecond, and multiplying that with 128 max payload is 256
microsecond just to read the message. Maybe this takes much longer
(there is quite a bit of overhead), but I would be very surprised if
it taks 2500-800 = 1700 microseconds longer than the regular 40ish
payload. Anyway, you might have your SPI bus set to a lower speed?

>> For these reason the base station
>> uses TASKLET_IS_TASK by default (set in the makefile). If you disable
>> this macro, then the base station works for some time and then locks
>> up.
>
> It is quite interesting as the blip-basestation does not use
> TASKLET_IS_TASK. Nevertheless, it works without any problem.
>
> At this stage, I believe that the meshbean900 implementation may have a bug
> somewhere, i.e. we do not correctly control the UART or the SPI.

Ok.

Best,
Miklos
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