Programming joysticks

[Dave Flowerday]

Originally Posted by NoRemorse

On the new joysticks, there is a mini - milt-direction "d-pad" i guess you could call it. How do you prgram this, or can you even. I can't find it anywhere in the code

It's called a "hat switch" and it'll show up as one of the analog joystick values to the robot controller. I can't remember if it appears as "Joystick Wheel" or "Joystick AUX" off the top of my head, though.

[NoRemorse]

well, the count of buttons on thejoistick does not equal the count of buttons in the program. and it is the odd man out.

[FotoPlasma]

The joystick's POV hat takes the place of the "pN_wheel", where N is the number of the joystick port you're using. I can only really speak for the joystick which I have right in front of me (the other is at my house, being used to play TIE Fighter ), so YMMV. The two least significant bits of the value change too erratically to be of any use. Here's a listing of the values of the variable when the POV hat is in different positions:
Neutral: 001011xx
Up Left: 111111xx
Up: 111111xx
Up Right: 111111xx
Left: 011000xx
Right: 110010xx
Down Left: 101001xx
Down: 100101xx
Down Right: 110101xx

The x's take the place of the two least significant bits, which, as I said earlier, change randomly (at least with this single joystick).

Basically, if you can understand binary, you can take advantage of the POV hat for controlling your robot.

Hope this helps.

[deltacoder1020]

Originally Posted by FotoPlasma

The joystick's POV hat takes the place of the "pN_wheel", where N is the number of the joystick port you're using. I can only really speak for the joystick which I have right in front of me
...
Neutral: 001011xx
Up Left: 111111xx
Up: 111111xx
Up Right: 111111xx
Left: 011000xx
Right: 110010xx
Down Left: 101001xx
Down: 100101xx
Down Right: 110101xx

our values for the joystick concur for the first 6 bits as well. (darn shame there is basically no difference between UL, U, and UR)

[Astronouth7303]

So the bit masks are:

const unsigned char Hat_None = 0x2C;
const unsigned char Hat_Up = 0xFC;
const unsigned char Hat_Left = 0x60;
const unsigned char Hat_Right = 0xC0;
const unsigned char Hat_Down = 0x94;

//Unless values are off, Combos aren't OR'ed
const unsigned char Hat_Up_Left = 0xFC;
const unsigned char Hat_Up_Right = 0xFC;
const unsigned char Hat_Down_Left = 0xA4;
const unsigned char Hat_Down_Right = 0xD4;

This seems a little stupid, but that's life.

[Chris Hleva]

I have a question, how could I add the right lines of code to make the POV hats work with the new C language this year? Amonst other things, where would I have to define them and map them to the right IO ports to work with the hex/bin input signal?

[Joe Ross]

Originally Posted by Astronouth7303

So the bit masks are:

const unsigned char Hat_None = 0x2C;
const unsigned char Hat_Up = 0xFC;
const unsigned char Hat_Left = 0x60;
const unsigned char Hat_Right = 0xC0;
const unsigned char Hat_Down = 0x94;

//Unless values are off, Combos aren't OR'ed
const unsigned char Hat_Up_Left = 0xFC;
const unsigned char Hat_Up_Right = 0xFC;
const unsigned char Hat_Down_Left = 0xA4;
const unsigned char Hat_Down_Right = 0xD4;

Why not #define them, instead of taking up memory?

[deltacoder1020]

Originally Posted by Chris Hleva

I have a question, how could I add the right lines of code to make the POV hats work with the new C language this year? Amonst other things, where would I have to define them and map them to the right IO ports to work with the hex/bin input signal?

example:

if( (p1_wheel & 0xC0) == 0xC0 )
{
     //hat control is pushed right
}
else if( (p1_wheel & 0xA4) == 0xA4 )
{
     //hat control is pushed down-left
}
...
et cetera
...

just use the bitwise AND function (&) to determine if the correct bits are set.

[Chris Hleva]

Thanks, that helped a lot. I am just starting out with C so i'm still a little sketchy with it.

[deltacoder1020]

no prob. if you want a review on the syntax of C, you could try the various guides in the whitepapers section, or the guide that I'm working on (see the thread in this forum titled "FIRST Programming Tutorial")

[Ryan Cumings]

Originally Posted by deltacoder1020

example:

if( (p1_wheel & 0xC0) == 0xC0 )
{
     //hat control is pushed right
}
else if( (p1_wheel & 0xA4) == 0xA4 )
{
     //hat control is pushed down-left
}
...
et cetera
...

just use the bitwise AND function (&) to determine if the correct bits are set.

Haven't been on for a while, but here goes (Sorry delta!)
If you push the hat up by your code then it will default to the first conditional statement you put in.

A more correct way might be to do it this way (using constants provided courtesy of Astronouth7303)

switch (px_wheel & 0xFC) {
	case Hat_Up_Left: {
		// ... Code here
		break;
	}
	case Hat_Up_Right: {
		// ... Code here
		break;
	}
	// etc...
	default: {
		break;
	}
}

[Robert Hafner]

Could someone help me out?

What I need is for someone to do out the etc. part of the

if( (p1_wheel & 0xC0) == 0xC0 )
{
//hat control is pushed right
}
else if( (p1_wheel & 0xA4) == 0xA4 )
{
//hat control is pushed down-left
}
...
et cetera
...


thing so I can do this right. I'm a tad but slow when it comes to binary and hex

[deltacoder1020]

here they are in binary, decimal, and hex forms...

Neutral: 001011xx 44 0x2C
Up Left: 111111xx 252 0xFC
Up: 111111xx 252 0xFC
Up Right: 111111xx 252 0xFC
Left: 011000xx 96 0x60
Right: 110010xx 200 0xCB
Down Left: 101001xx 164 0xA4
Down: 100101xx 148 0x94
Down Right: 110101xx 212 0xD4

Here's a diagram that gives the full range of values and the value to test with AND is bold.

252-255*252-255*252-255
*96-99***44-47**200-203
164-167*148-151*212-215

[Robert Hafner]

Because the last bits are unreliable (from what i've read), how will this affect the program? Should I stick with a general area? example:

if (p1_wheel >= 42 && p1_wheel <= 46)
    // I am neutral
if (p1_wheel >= 250 && p1_wheel <= 254)
     // I am upperleft;