LCD in Pre_Auton Problem

VEX V5 Technical Support
1

I’m having trouble using my lcd in pre_auton. I’m using a


while(vrDisabled == 1)

to run it but it is giving me a minor error (‘while’ expression is constant ‘false’. Loop never executed) and chooses not to run it, instead it displays that the robot is disabled and a count for how long it had been disabled. I have tried just changing the while loop to true, but then it never enters autonomous or driver control.

2

vrDisabled is the wrong thing to be using, the correct code would be;


while(bIfiRobotDisabled) {
  // Run some code
  }

I’m not sure where you found the vrDisabled flag, that would be used with the variable nVexRCReceiveState to manually check the raw data. vrDisabled is more or less a constant (it’s part of an enumerated type), here is the definition from the header file.

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;

It has the value 0x80 (which is 128 in decimal) so a statement like

if(vrDisabled == 1)

will never be true as 128 is not equal to 1.

3

Thank you so much, now I can select our autonomous and see all the debugging data we need. Problems solved.

4

Thanks @jpearman, That was my team’s programmer asking the question, and you helped him a ton. He’s a first year programmer and he’s is so much more confident programming knowing that he can ask questions here.