Vex SquareBot- movement programming problem

[Nathan]

Hi, I'm programming the Vex SquareBot in MPLAB IDE, and am having some problems programming the movement since one of the motors on the SquareBot is inverted. I tried this code:

void normal_operation()
{
	int R_Joy_Up    = 127;		// These hold the joystick values.
	int L_Joy_Up    = 127;		// Only R_Joy_Up & L_Joy_Up are used in tank mode.
	int R_Joy_Down  = 127;		// This probably isn't really needed, to be cleaned up after project completed.
	int L_Joy_Down  = 127;
	int R_Joy_Right = 127;
	int L_Joy_Right = 127;
	int R_Joy_Left  = 127;
	int L_Joy_Left  = 127;
	
	int temp;
	
	while(autonomous != 255)
	{
		R_Joy_Up = GetRxInput( 1,2 );
		L_Joy_Up = GetRxInput( 1,3 );
		
		if(L_Joy_Up > NEUTRAL)
		{
			temp = L_Joy_Up - 127;
			L_Joy_Up = NEUTRAL - temp;
		}
		else if(L_Joy_Up < NEUTRAL)
		{
			temp = L_Joy_Up - 127;
			L_Joy_Up = NEUTRAL - temp;
			if(L_Joy_Up <= 0)
			{
				L_Joy_Up = 253;
			}
		}

		autonomous = GetRxInput(1,5);
		drive ( R_Joy_Up, L_Joy_Up );
		PrintToScreen ( "L_Joy_Up: %d\n" , (int)L_Joy_Up );
		Wait(1);
	}

My code works fine, until I move the left joystick on the vex controller all the way to the bottom. The the motor suddenly reverses direction

Does anyone have any suggestions? I really appreciate the help

Thanks,
Nathan