There is TinyOS interface BusyWait which is provided by components
BusyWaitMicaC.
That might solve your problem.
Faisal
zahid iqbal wrote:
> Hi,
>
> I am writing a simulation for wireless sensor networks under TOSSIM.
>
>
> I know TOSSIM keeps time track in terms of simulation ticks. I am
> using the following version of TinyOS, tinyos-2.1.0. Under this
> version, I have 10^10 or 100,00,00,00,00 simulation ticks per second.
> I get this value from /tos/lib/tossim/sim_tossim.c
>
> sim_time_t sim_ticks_per_sec() __attribute__ ((C, spontaneous)) {
> return 10000000000ULL;
> }
>
> Now, coming to my question, how would I pause for a specific number of
> simulation ticks.
>
> Actually, I am simulating the behavior of a hardware board where there
> are different pauses involved. The pauses are in milliseconds or
> microseconds.
>
> I tried this problem several ways, but still I am not successful.
>
> First Approach:
>
> If I just use the C functions like usleep, or sleep. That does not
> serve the purpose,
>
> i.e. according to given configuration:
>
> 1 milli second = 10^7 simulation ticks
> 1 micro second = 10^4 simulation ticks
>
> For example if I have the following scenario:
>
> void main_function(){
> function_A();
> usleep(25); // 25 micro seconds
> function_B();
> usleep(25)
> }
>
> Now, let us say, if current time as returned by sim_time() was 123456
> after function_A(), Then it should be (123456 + 2500,00) in terms of
> simulation ticks after the usleep function is over. but it gives me
> the same time even after the usleep.
>
> Second Approach:
>
> Next, I tried to enqueue an event for the corresponding function in
> the simulation queue with a timestamp equal to (current time + desired
> pause in simulation ticks). Still, I have a problem. Letus again
> consider the same scenario
>
> I make a strucutre,
>
> struct funct{
> void(*fp)(); // The function to be executed.
> int node_id;
> };
>
> typedef funct funct_t;
>
> void handle_last(void(*fp)()){
> fp();
> }
>
> void sim_gain_handle(sim_event_t* evt){
> funct_t* f = (funct_t*)evt->data;
> handle_last(f->fp);
> }
>
> sim_event_t* allocate_event(long t, funct_t* g) {
> sim_time_t cT;
> sim_event_t* evt;
>
> cT = sim_time();
>
> evt = (sim_event_t*)malloc(sizeof(sim_event_t));
> evt->mote = sim_node();
> evt->time = cT+t; // desired time stamp
> evt->handle = sim_gain_handle;
> evt->cleanup = sim_queue_cleanup_event;
> evt->cancelled = 0;
> evt->force = 0;
> evt->data = g;
>
> return evt;
> }
>
> With the above scenario, I can now enqueue events in TOSSIM event
> queue with desired timestamps. Therefore, the following
>
> void main_function(){
> function_A();
> usleep(25); // 25 micro seconds
> function_B();
> usleep(25)
> function_C();
> }
>
> would look something like:
>
> void main_function(){
> function_A();
> evt = allocate_event(250000, function_B());
> evt = allocate_event(250000, function_C());
> }
>
> Now the problem here is the following.
>
> 1. I want that, function_C would be processed only after function_B is
> executed and done. But in the above scenario this does not happen, as
> main_function simply enqueues both function_B and function_C at about
> the same time.
>
> 2. Since, at some later time, the handler will eventually call
> function_B, the control is not with the main function however, One
> solution could be that when function_B is done, I then enqueue the
> function_C, but that makes it a lot messy. Especially, If there are
> many nested function calls.
>
>
> If there was a something simpler like
> sim_pause(250000) // pause for 25 micro seconds,
>
> it would have been much easier.
>
> Any, help would be much appreciated.
>
> regards,
> Zahid Iqbal
>
>
>
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>
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