# Beginning programmer: Variable question HELP!!!

OK i’m going to be sitting by my computer refreshing every 30 seconds checking for reply :ahh:

In file user_routines.c, under

/***DEFINE USER VARIBLES AND INITIALIZE THEM HERE ***/
static unsigned int bob = 2;

Now under the:
Void Default_Routine(void)
{
if(bob == 2 && p1_sw_trig){bob = 0;}
if(bob == 0 && p1_sw_trig){bob = 1;}
if(bob == 1 && p1_sw_trig){bob = 0;}

}

Before I click on the trigger, I get the value 2 for bob…
Click on it once, I get 0
click on it again I get 0(it’s suppose to change to 1)

WHAT AM I DOING WRONG!?!!?

Your problem is that you set bob to 1 and then check to see if it is 1 and the button is pressed and set it back to 0.

``````if(bob == 2 && p1_sw_trig)
{
bob = 0;
}
/** assuming bob == 0, bob is set to 1 ****/
if(bob == 0 && p1_sw_trig)
{
bob = 1;
}
/** bob is now 1 and gets set to 0 ****/
if(bob == 1 && p1_sw_trig)
{
bob = 0;
}
/*** bob is always 0 if the trigger has been pressed ***/
``````

You can fix this with by using an else if.

``````static unsigned int bob = 2;

Void Default_Routine(void)
{
if(bob == 2 && p1_sw_trig)
{
bob = 0;
}
else if(bob == 0 && p1_sw_trig)
{
bob = 1;
}
else if(bob == 1 && p1_sw_trig)
{
bob = 0;
}
}
``````

Once you do that you’re going to run into the problem that the state is constantly toggling between 0 and 1 when the button is pressed.

This is because there is no way that you as a user will be able to tap the trigger for 1 loop (1/42 of a second) and the trigger will actually be pressed for multiple loops.

What I think you want to do is keep track of the previous button state and only change states if your current state is pressed and your previous is not.

Try this:

Void Default_Routine(void)
{
static unsigned int trigger_count = 0;

if(p1_sw_trig)
{
++trigger_count; //sets a trigger counter to control the value
}
else
{
}
if(trigger_count > 1) //Change as needed
{
trigger_count = 0; //Resets trigger count
}
else
{
}

if(bob == 2 && p1_sw_trig && trigger_count == 0)
{
bob = 0;
}
else if(bob == 0 && p1_sw_trig && trigger_count == 1)
{
bob = 1;
}
else
{
}

}

It takes about 400 to 600 nanoseconds (maybe a bit more) for the three IF statements to execute. You cannot hit the trigger fast enough to satisfy only one IF statement.

The first time through, bob goes from 2 to 0.

The next time though, bob goes from 0 to 1 to 0.

The code is doing exactly what you told it to do…

Regards,

Mike

wow thanks for the quick reply,
I figured out a way to do it with two buttons. Now it works fine.

I completely forgot about the quick loop, and started questioning my programming skills.

``````/////**** Start of RELAY 7 code ****/////
if(bob7 == 0)
{
printf("Bob7 = 0\r");
relay7_fwd = 1;
}
if(bob7 == 1)
{
printf("Bob7 = 1\r");
relay7_fwd = 0;
}
if(bob7 == 2){printf("Bob7 = 2\r");}

if(bob7 == 2 && p1_sw_trig){bob7 = 0;}
if(bob7 == 0 && p1_sw_top){bob7 = 1;}
if(bob7 == 1 && p1_sw_trig){bob7 = 0;}
/////**** End of RELAY 7 code ****/////
``````