!HELP! IM STUCK IN A SUBROUTINE!!! !HELP!

[cdennisxlx2]

Im developing a set of subroutines to make it easyer for my teams programmers. But when i tried to show them how to call them it calls the first one and stays.

example: From user_routines_fast.c

This is the autonomous code i made to test calling subroutines [line: 141]

/*******Autonomy Notes*********************
* "time" was initalized on line 24
* relay1_fwd/rev = Bottom Cylinder
* relay3_fwd/rev = Top Cylinder
*	    pwm01 = Left Drive motor
*           pwm02 = Right Drive motor
*           pwm03 = Shooter
*           pwm04 = Tilt
*	  26 loops = One Second (roughly)
****************************************/		
                 
if (time >= 0 && time < 50)
{	
	Left();
}
else if (time > 50 && time < 100)
{
	Stop();
}
else if (time > 100 && time < 150)
{ 
	Right();
}
else if (time > 150)
{
	pwm01 = pwm02 = 127;
}
time++;  //Incriment time

These are the subroutines [line: 290 in user_routines_fast.c]

unsigned char Left()
{
	pwm01 = 0;
	pwm02 = 254;
	return 0;	
}

unsigned char Right()
{
	pwm01 = 254;
	pwm02 = 0;
	return 0;	
}

unsigned char Stop()
{
	pwm01 = pwm02 = 127;
	return 0;
}

The FUNCTION PROTOTYPES for the subroutines in user_routines.h

unsigned char Left(void);
unsigned char Right(void);
unsigned char Stop(void);

Can anyone tell me why when i run this it stays in Left()??????????


thank you in advanced

[Mike Betts]

Cameron,

I can not identify exactly where your problem is. Here are some ideas.

I would add a check after incrementing time and set time = 0 if time < 0.

I would look at where time is declared and insure that it is static. Beware of dynamic initializations...

As a matter of style, I would use the form ((A > B) && (A < C)) rather than (A > B && A < C) when working with students. It adds nothing to the speed of the code and eliminates the memorization of operator precedence.

Lastly, I would add a printf to determine what is going on. I strongly suspect the initialization of time is either implicit or the variable is getting stepped on between loops.

Regards,

Mike

[Stuart]

well first you have 3 holes
50 100 and 150.

dont think that will fix the problem. but at 6am thats all that I can see is wrong.

[Mark McLeod]

After you get past the "Left();" problem, "time" will eventually wrap around to 0 and start all over again depending on how you've declared it.

I vote with Mike. It seems like "time" could easily be a local variable and thus always be 0. If you remove the "=" from "if (time >= 0 && time < 50)" it would probably not even do "Left()".

P.S.
It's 38 loops per second (26.2 milliseconds per loop) on the FRC.
Why didn't you choose to call Stop() at the end?

[KenWittlief]

printf is your best debug friend

computers have a nasty habit of doing exactly what you tell them to do

instead of what you want them to do

whenever a program is not doing what you expected, printf the variables to see whats going on inside the SW

in fact, you should get in the habit of checking SW modules this way, to make sure it is doing exactly what you thought it would do (module level testing). Then if its working correctly take the debug (printf...) statements out, or have a debug variable that you set to 0 to disable them.

[JamesBrown]

Assuming he didn't change the comment at the beginning of the code (which I am guessing he didn't because other wise the line numbers don't do much good) then he initialized time in the right place.

The only problem I could see there is if you just declared time and didn't initialize it. Assuming you initialized it as 0 I don't see that as being your problem. I am not sure if it is enough to cause the problem you have but at the very least it is sloppy to return a value through the function if you aren't assigning it to anything.

If you still can't figure out the problem, post all of your user_routine_fast.c and we can probably help more.

James

[Daisy]

After running it in my head (which may not be accurate), I think time is the problem. You're incrementing time, so that after 49, it reaches 50, but at it, you do not define what it does with it (ie Left() or Stop(), etc), so it will keep repeating left.

Daisy

[Dave Scheck]

Originally Posted by Daisy

After running it in my head (which may not be accurate), I think time is the problem. You're incrementing time, so that after 49, it reaches 50, but at it, you do not define what it does with it (ie Left() or Stop(), etc), so it will keep repeating left.Daisy

Yeah, but time gets incremented outside of the if statements. Unless he is clearing the PWM values somewhere, whatever was set in Left will still be sent to the motors for an additional cycle. If he is clearing the values, there would be a 1 cycle pause in the PWM output.

I agree with what was said above. Most likely the time variable isn't global or statically defined. Debug prints should make this apparent rather quickly if this is the case.

[cdennisxlx2]

Time is not the problem, that part works great. All i need to know is did i code the subroutines wrong or am i calling them wrong? If im doing those right then why is the code stuck in Left() when i run the robot in autonomous mode?

[Mark McLeod]

Post a zip of your user_routines_fast.c here and we'll tell you.

Right now it looks like you're taking something for granted when you post the problem and not bothering to tell us about some seemingly unimportant detail. In programming all details are important. If you weren't overlooking something your code would be working. As with most bugs you don't know what the important detail is yet.

[Alan Anderson]

Originally Posted by ghhs_1527

Time is not the problem, that part works great.

How do you know that? My first guess is that you're "initializing" the time variable every time through the loop, so it is always equal to zero when you hit the if statement.

Speaking of "the loop", what is causing it to run 26 times per second? We definitely need to see more of the code in order to help you.

[Stuart]

ok its now 5pm and Im awake

ok 50% chance your resetting time to be = to 0 every time you loop.

30% chance that that loop isnt happening every 26 secs(I know it says "im fast I run every 26.1 secs" but its a liar liar pants on fire)

20% chance its something else

[cdennisxlx2]

I know it works because it works in all the other modes, just not the one with the subroutines, we have a dip switch to choose autonomous modes. but here are the user_routines_fast.c and user_routines.h files (attached)

[Alan Anderson]

	if (rc_dig_in11 = 1) /* 1st Autonomy code */

There's your problem right there. You just tried to assign the value 1 to the variable rc_dig_in11. To test for equality, you must use the == symbol, with two equal signs.

The code you posted will always run the BASH routine. You need to change all those single = to double == in your if and else if statements.

[JamesBrown]

Originally Posted by Alan Anderson

	if (rc_dig_in11 = 1) /* 1st Autonomy code */

There's your problem right there. You just tried to assign the value 1 to the variable rc_dig_in11. To test for equality, you must use the == symbol, with two equal signs.

The code you posted will always run the BASH routine. You need to change all those single = to double == in your if and else if statements.

Yep, that would be it.

As a note to any one else who ever needs help the more code you post the better we can help, don't worry about people stealing it, it wont work on our robots anyway.

James