[Tinyos-help] [tinyos2.0] event timer.fired() getting lost on telosb using BlinkToRadio apps.

[Philip Levis]

On Jul 23, 2006, at 11:37 AM, Jonathan Hui wrote:

> After a little testing, it looks like the radio stack is still alive.
> I modified BlinkToRadio to maintain two timers (1ms and 1s period),
> both of which attemps to send a message on each fire event. After a
> few moments, the 1ms timer will fail to fire, but the 1s timer will
> continue firing and sending messages. Even more interesting is that
> the 1ms timer starts firing at the same period as the 1s timer.
>
> It's probably the case that the radio stack is somehow affecting the
> operation of the msp430 timer stack and causing it to fail in
> repeatedly firing the 1ms timer. Haven't dug too much into the timer
> code to understand why this is.
>
> I've attached the modified app I used to test.
>
> Cory, do you have an ideas?

Yeah, I should have given more background. I think it's definitely  
the case that it's the MSP430 timer stack, which runs into some  
issues when timers are at too fast a rate (e.g., 1ms). E.g., in the  
2.0 tutorials, there's a part where you try using very long tasks of  
different length to show the run-to-completion semantics. On atm128  
platforms, a task that's too long causes you to lose timer events but  
things continue as expected; on msp430 ones, the timer stack can act  
erratically.

Joe, Cory, does Boomerang 2.0.2 use the 2.x timer stack unchanged, or  
have you incorporated fixes?

Phil