I'am currently working on tinyos and I Am trying to reset timer
lets say to 2 seconds when it is running at 45 seconds
but it is not working, i can't figure out why,
can someone help me figure it out
here is the code:
printf("timer before resetting it %ld",call Timer1.getNow());
offset = ((TimeMote_t*) payload)->tdata;
call Timer1.startPeriodic(offset);
printf("timer after resetting it %ld",call Timer1.getNow());
now actually it should have reset the timer to offset but it's not resetting it.
both printf statements are giving the same time.
No, it shouldn't. Timer.getNow() returns absolute time, which can't be changed or reset. Timer interface can be used to schedule events at a particular moment in the future. Timer.startPeriodic(offset) starts the timer, meaning that the event Timer.fired() will be signaled in the future. In this particular example, the event will be signaled offset units from the call to Timer.startPeriodic and then repeated every offset units infinitely or until call to Timer.stop(). Return value of Timer.getNow() doesn't change and increases monotonically regardless of whether the timer is started or not.
See: Interface: tos.lib.timer.Timer
Related
Has anyone heard of a hardware-timer which can count by different values with one timer tick?
Normally a timer of a µC counts up or down by one. But I have a challenge where I need to add e.g. 500 each timer tick.
There are multiple options for your question. Depending on your microcontroller and timer you could:
Use the interrupt generation of the timer to manually up a variable by a set amount. 500 in your case.
Change the timer prescalers such that instead of 500 times in an expected period, the timer only triggers once during the expected period.
I personally don't know of a timer that has a variable increase amount but that doesn't mean that it doesn't exist. Maybe creating such a timer in VHDL or verilog may be a option.
I'm currently working on a simulation where i've programmed turtles to move faster when they reach a specific number of ticks. Given this reason i have to reset the ticks to make the command go over and over again. What i want to do is to see the final sum of ticks that has been run through the entire simulation but with the reset tick command, i can only see how many ticks has been run since the last time i used the move command on my turtles. This makes it impossible for me to use the "monitor" in my interface to show ticks. So how do i see the final count of ticks that has been run since i started the simulation, and not only since the last time it reset the ticks.
To do what you describe, you could create a global variable (say, tickTotal), increment it each tick, and add a monitor to the interface.
But what you should do instead is stop resetting ticks. Instead, use the mod command to control your cyclical response of turtle movement to the tick count.
I'm creating a card game in pygame for my college project, and a large aspect of the game is how the game's AI reacts to the current situation. I have a function to randomly generate a number within 2 parameters, and this is how long I want the program to wait.
All of the code on my ai is contained within an if statement, and once called I want the program to wait generated amount of time, and then make it's decision on what to do.
Originally I had:
pygame.time.delay(calcAISpeed(AIspeed))
This would work well, if it didn't pause the rest of the program whilst the AI is waiting, stopping the user from interacting with the program. This means I cannot use while loops to create my timer either.
What is the best way to work around this without going into multi-threading or other complex solutions? My project is due in soon and I don't want to make massive changes. I've tried using pygame.time.Clock functions to compare the current time to the generated one, but resetting the clock once the operation has been performed has proved troublesome.
Thanks for the help and I look forward to your input.
The easiest way around this would be to have a variable within your AI called something like "wait" and set it to a random number (of course it will have to be tweaked to your program speed... I'll explain in the code below.). Then in your update function have a conditional that waits to see if that wait number is zero or below, and if not subtract a certain amount of time from it. Below is a basic set of code to explain this...
class AI(object):
def __init__(self):
#put the stuff you want in your ai in here
self.currentwait = 100
#^^^ All you need is this variable defined somewhere
#If you want a static number as your wait time add this variable
self.wait = 100 #Your number here
def updateAI(self):
#If the wait number is less than zero then do stuff
if self.currentwait <= 0:
#Do your AI stuff here
else:
#Based on your game's tick speed and how long you want
#your AI to wait you can change the amount removed from
#your "current wait" variable
self.currentwait -= 100 #Your number here
To give you an idea of what is going on above, you have a variable called currentwait. This variable describes the time left the program has to wait. If this number is greater than 0, there is still time to wait, so nothing will get executed. However, time will be subtracted from this variable so every tick there is less time to wait. You can control this rate by using the clock tick rate. For example, if you clock rate is set to 60, then you can make the program wait 1 second by setting currentwait to 60 and taking 1 off every tick until the number reaches zero.
Like I said this is very basic so you will probably have to change it to fit your program slightly, but it should do the trick. Hope this helps you and good luck with your project :)
The other option is to create a timer event on the event queue and listen for it in the event loop: How can I detect if the user has double-clicked in pygame?
So I have to implement a discrete event cpu scheduler for my OS class, but I don't quite understand what how it works. Every explanation/textbook I've read always put things in terms a little too abstract for me to be able to figure out how it actually works, nor does it put things in terms of cpu bursts and io bursts (some did but still not helpful enough).
I'm not posting any of the code I have (I wrote a lot actually but I think I'm going to rewrite it after I figure out (in the words of Trump) what is actually going on). Instead I just want help to figure out a sort of pseudocode I can then implement.
We are given multiple processes with an Arrival Time (AT), Total Cpu (TC), Cpu burst (CB), and Io burst (IO).
Suppose that I was given: p1 (AT=1, TC=200, CB=10, IO=20) and p2 (AT=1000, TC=200, CB=20, IO=10). And suppose I am implementing a First Come First Serve scheduler.
I also put question marks (?) where I'm not sure.
Put all processes into eventQ
initialize all processes.state = CREATED
While(eventQueue not empty) process = eventQueue.getFront()
if process.state==CREATED state, it can transition to ready
clock= process.AT
process.state = READY
then I add it back to the end (?) of the eventQueue.
if process.state==READY, it can transition to run
clock= process.AT + process.CPU_time_had + process.IO_time_had (?)
CPU_Burst = process.CB * Rand(b/w 0 and process.CB)
if (CB >= process.TC - process.CPU_time_had)
then it's done I don't add it back
process.finish_time = clock + CB
continue
else
process.CPU_time_had += CB
(?) Not sure if I put the process into BLOCK or READY here
Add it to the back of eventQueue (?)
if process.state==BLOCK
No idea what happens (?)
Or do things never get Blocked in FCFS (which would make sense)
Also how do IO bursts enter into this picture???
Thanks for the help guys!
Look at arrival time of each thread, you can sort the queue such that arrival times occurring first appear before threads with later arrival times. Run the front of the queue's thread (this is a thread scheduler). Run the thread a burst at a time, when the burst's cpu time is up, enter a new event at the back of the queue with an arrival time of the current time plus the burst's io time (sort the queue again on arrival times). This way other threads can execute while a thread is performing io.
(My answer is assuming you are in the same class as me. [CIS*3110])
I have been making a labview program for kids to moniter energy production from various types of power sources. I have a condition where if they are underproducing a warning will fire, and if they are overproducing by a certian threshold, another warning will fire.
I would like to time how long throughout the activity, each type of warning is fired so each group will have a score at the end. This is just to simulate how the eventual program will behave.
Currently I have a timer which can derrive the amount of time the warning is true, but it will overwrite itself each time the warning goes off and on again.
So basically I need to to sum up the total time that the value has been true, even when it has flitted between true and false.
One method of tabulating the total time spent "True" would be exporting the Warning indicator from the While-loop using an indexed tunnel. If you also export from the loop a millisecond counter value of when the indicator was triggered, you can post process what will be an array of True/False values with the corresponding time at which the value transitioned.
The post processing could be a for-loop that keeps a running total of time spent true.
P.s. if you export your code as a VI snippet, others will be able to directly examine and modify the code without needing to remake it from scratch. See the NI webpage on the subject:
http://www.ni.com/white-paper/9330/en/
I would suggest going another way. Personally, I found the code you used confusing, since you subtract the tick count from the value in the shift register, which may work, but doesn't make any logical sense.
Instead, I would suggest turning this into a subVI which does the following:
Keep the current boolean value, the running total and the last reset time in shift registers.
Initialize these SRs on the first call using the first call primitive and a case structure.
If the value changes from F to T (compare the input to the SR), update the start time.
If it changes from T to F, subtract the start time from the current time and add that to the total.
I didn't actually code this now, so there may be holes there, but I'm leaving that as an exercise. Also, I would suggest making the VI reentrant. That way, you can simply call it a second time to get the same functionality for the second timer.