Vex Brain problems

VEX V5 Technical Support UNOFFICIAL Tech Support
#1

A team we are mentoring is having difficulty with their vex brain. They can download code, and firmware. If they download autonomous the motors will move but to drive there is no response. Is there anyone who can help us figure out what is wrong with the brain?

#2

more info would be helpful
what micro-controller are you using?
what programmer are you using?
what version is the firmware?
upload your code
ect…

with the information you given, it will be extremely hard for us to try to figure out your problem

#3

We are using the vex cortex. (The one with the hump on it.)
Also the latest version of robot c (3.02 or something)
Task main()
{
while(true)
{
motor[port3] =127;
wait1msec(1000);
motor[port2] =vexRT[ch2];
}
}
This code should run motor 3 constantly since the code is in the while loop. While motor port 2 can be driven by the joystick with channel 2.
Also we tried this code with the same results of not being able to drive the motor with the joystick.
Task main()
{
while(true)
{
motor[port2] =vexRT[ch2];
}
}

I tried updating firmware for the joystick/cortex, and also synced them together by tethering.

#4

A few things to check and try and some comments.

  1. Make sure you have the latest firmware in both cortex and joystick. RobotC V3.02 needs master firmware 3.16. You can do a software inspection (Robot->VEX Troubleshooter->Software Inspection ) to check all the versions and also that battery voltages are good. Obviously make sure the motor is connected to the correct port and battery is good etc.

  2. You can check that the joysticks are working in V3.02 using the new VEXnet joystick viewer (Robot->VEX Troubleshooter->VEXnet joystick viewer ). This assumes you are connected using the programming cable into the back of the joystick.

  3. Select “Download using VEXnet or USB” for the download method rather than competition for now.

  4. Your first example code will only sample the joystick once every second (due to the wait1msec(1000) in the loop) which would make control very intermittant. The second example should work but is hogging the CPU as there is no delay. Try the following, I added a variable “value” that you can look at in the debugger, open the global variables debug window.

#pragma config(Motor,  port2,           TheMotor,      tmotorNormal, openLoop)
//*!!Code automatically generated by 'ROBOTC' configuration wizard               !!*//

task main()
{
    int value;

    while( true )
        {
        value = vexRT Ch2 ];

        motor port2 ] = value;

        wait1Msec(25);
        }
}
#5