The students are looking to create a couple classes that run as tasks during the life of the robot. They have used the compressor as the model of the classes. The compressor uses digital I/O directly but not the encoder class. The code compiles and we can download the image. The robot starts and the class in created without errors. When we start the class we get this error:
DisabledContinuou
DisableDribbler -> Access Dribbler State Machine1
data access
Exception current instruction address: 0x0232125c
Machine Status Register: 0x0000b032
Data Access Register: 0xfeffebff
Condition Register: 0x20000044
Data storage interrupt Register: 0x40000000
Task: 0x1d85ff8 “FRC_Dribbler”
0x1d85ff8 (FRC_Dribbler): task 0x1d85ff8 has had a failure and has been stopped.
0x1d85ff8 (FRC_Dribbler): fatal kernel task-level exception!
The victors and the encoders are not referenced in any other part of the code. From the error you see that it gets to the first print statement and errors when it tries to access the encoder.
Here are some parts of the source:
//A File Scope Function out side of the class
static void AccessDribblerStateMachine(Dribbler *d)
{
printf("Dribbler -> Access Dribbler State Machine1
");
//d->DribblerStateMachine();
double LeftDriveRate = d->LeftEncoder->GetRate();
printf("Dribbler -> Access Dribbler State Machine2<%f>
", LeftDriveRate);
}
Here is the construct of the class with the task and the creation of a couple victors and encoders.
Dribbler::Dribbler(DashSharing *DashDataPass)
: DribblerTask(“Dribbler”, (FUNCPTR) AccessDribblerStateMachine)
{
LeftDribbler = new Victor(DIO_MODULE1, LEFT_DRIBBLING_MOTOR_CHANNEL);
RightDribbler = new Victor(DIO_MODULE1, RIGHT_DRIBBLING_MOTOR_CHANNEL);
DashData = DashDataPass;
LeftEncoder = new Encoder(DIO_MODULE1, LEFT_MOTOR_ENCODER_CHANNEL_A, DIO_MODULE1, LEFT_MOTOR_ENCODER_CHANNEL_B, ENCODER_DISTANCEPERPULSE);
RightEncoder = new Encoder(DIO_MODULE1, RIGHT_MOTOR_ENCODER_CHANNEL_A, DIO_MODULE1, RIGHT_MOTOR_ENCODER_CHANNEL_B, ENCODER_DISTANCEPERPULSE);
Looks like an uninitilized pointer is being dereferenced, but I can’t tell for sure unless you post the whole source file to show how things are called and when.
I have uploaded the files for the dribbler. It is created in the dribbler class is created in the main Iterative robot and defined in its .h file. Segments of the main robot included at the end to show order of creation.
The Dashboard is past in from to the constructor and appears to have the same issues.
AccessDribblerStateMachine(Dribbler *d) (a file scoped function) called the dribbler class statemachine, but during testing we moved the encoder to see if there was different results and there was no change in the error. In the statemachine we commented out // DashData-> to work on one issue at the time, this also goes for the victors at the end of the function that result in the same error.
Parts from our Main robot:
Breakaway10::Breakaway10(void) : camera(AxisCamera::GetInstance())
{
//Robot Base Drive Initializers:
//Gamepad Initializers:
//Gyro Initializers:
//PID Output Initializers:
//TurnController Initializers USES PID OUTPUT, USES GYRO
//Dashboard Initializers:
dds = new DashboardDataSender();
//Compressor Initializers:
compressor = new Compressor(COMPRESS_PRESSURE_SWITCH_CHANNEL, COMPRESS_RELAY_CHANNEL);
//Encoder Initializers: (were passed to dribbler but now created within dribbler
// leftEncoder = new Encoder(DIO_MODULE1, LEFT_MOTOR_ENCODER_CHANNEL_A, DIO_MODULE1, LEFT_MOTOR_ENCODER_CHANNEL_B, ENCODER_DISTANCEPERPULSE);
// rightEncoder = new Encoder(DIO_MODULE1, RIGHT_MOTOR_ENCODER_CHANNEL_A, DIO_MODULE1, RIGHT_MOTOR_ENCODER_CHANNEL_B, ENCODER_DISTANCEPERPULSE);
//Dash Sharing Initializers:
DashData = new DashSharing();
//Dribbler Initializers: USES DASH DATA
dribbler = new Dribbler(DashData);
…
void Breakaway10::TeleopContinuous(void)
{
//We need to start these tasks before we begin the loop, to use the enable function
//ChaosKicker->Start();
//Wait(0.5);
dribbler->Start();
In the original version we passed in the encoders and we ran the Keep code in the Iterative robot without issue. The students wanted it to run all the time since it was needed as long as the robot was enabled.
Hi,
We have done some more work with this and it appears that some classes like encoder, dashboard are not thread safe. We are able to include joystick, digital I/O and analog, without an error. Has anyone else try including encoders in a task and if so did they have errors while the oRICO ran?
we use tasks, but have only one task access the sensors, the other must ask the first for the value. You could also use semaphores: http://www.chiefdelphi.com/forums/showthread.php?t=82398
also, could you use [CODE ] Tags on your posts? It helps a lot. (the # button in the editor)
