Seeing if a partner controller is connected using RobotC

VEX V5 General Discussion Technical Discussion
#1

I am trying to create two versions of my driver control code, on that runs if a partner controller is connected, one that runs if it is not. a search in the forums turned up this as a method of telling


	if( nVexRCReceiveState & 0x01 )
    {
    	player1 = true;
    // first joystick is connected
    }
if( nVexRCReceiveState & 0x02 )
    {
    	player2 = true;
    // second joystick is connected
    }

however that post was from 2012.
the problem I am finding is that both of those IF statements always seem to return true.
am i doing something wrong, or does this method not work with current versions of robotC, does any one know a way of doing this?

#2

Linking to a particular post is almost impossible now, so here is some code from the “ROBOTC programming tips” thread I posted a couple of years ago. The above code is correct, you can only have the partner joystick if the main joystick is also available.

// send some useful information to the debug stream
void
PrintnVexRCReceiveState()
{
    if( (nVexRCReceiveState & (vrXmit1 | vrXmit2)) == (vrXmit1 | vrXmit2) )
        writeDebugStreamLine("Transmitter 1 and 2 connected");
    else
    if( nVexRCReceiveState & vrXmit1 )
        writeDebugStreamLine("Transmitter 1 connected");
    else
    if( nVexRCReceiveState & vrXmit2 )
        writeDebugStreamLine("Transmitter 2 connected");
    
    if( nVexRCReceiveState & vrCompetitionSwitch )
        writeDebugStreamLine("Competition switch is connected");
    else
        writeDebugStreamLine("Competition switch not connected");
    
}

// Monitor nVexRCReceiveState and show changes
task main()
{
    unsigned int rcReceiveState      = 0;
    unsigned int last_rcReceiveState = 1; // cause print on program entry
    
    while(1)
        {
        rcReceiveState = nVexRCReceiveState   
        
        if( rcReceiveState != last_rcReceiveState )
            {
            writeDebugStreamLine("rcReceiveState is %02X", rcReceiveState );
            last_rcReceiveState = rcReceiveState;
            PrintnVexRCReceiveState();
            }
            
        wait1Msec(25);
        }
}
#3

ok you said the code I had above was correct, but it is not working, both if statements always return true, regardless of how many controllers are connected. Then the code you posted was different should I use “vrXmit1” in place of ‘0x01’ and “vrXmit2” in place of "0x02’?

#4

Strange. Here are the definitions, they are the same.

  typedef enum
  {
    vrNoXmiters           = 0,        // No transmitters connected
    vrXmit1               = 0x01,     //                          1 == Transmitter 1 connected
    vrXmit2               = 0x02,     //                          1 == Transmitter 2 connected
    vrBit2                = 0x04,     // Unused
    vrCompetitionSwitch   = 0x08,     // 0 == No Comp Switch      1 == Competition Switch attached.
    vrResetSlave          = 0x10,     // Unused
    vrGameController      = 0x20,     // 0 == Legacy75MHz,        1 == Game Controller
    vrAutonomousMode      = 0x40,     // 0 == Driver Control,     1 == Autonomous Mode
    vrDisabled            = 0x80,     // 0 == Enabled             1 == Disabled.
  } TVexReceiverState;
#5

ok, hmm perhaps I am confused, should “transmitter 2” be the partner controller?

#6

Yes, let me check it out tomorrow to make sure everything is still working.

#7

If the 2nd transmitter is connected, the first must also be connected.

This is the code I used in Toss up when I last did vex.
It assumes that there will not be 0 controllers.

		if (nVexRCReceiveState & vrXmit2)//if 2 controler
		{

		}
		else//if 1 controler
		{

		}
#8

http://puu.sh/minqh.png

https://vexforum.com/index.php/conversation/post/85246

i dont understand why this is the only way to do it :frowning:

#9

Ok, so right click on the post date, thanks, not obvious but at least it can be done.

#10

Code still works correctly in V4.52.

#11

Ok thanks for the Update, we were seeing some other weird behavior from the partner controller as well, so I will look into checking it with a different partner controller

#12