Ultrasonic.h

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2008. All Rights Reserved.                             */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in $(WIND_BASE)/WPILib.  */
/*----------------------------------------------------------------------------*/

#ifndef ULTRASONIC_H_
#define ULTRASONIC_H_

#include "SensorBase.h"
#include "Task.h"
#include "PIDSource.h"
#include "LiveWindow/LiveWindowSendable.h"

class Counter;
class DigitalInput;
class DigitalOutput;

class Ultrasonic: public SensorBase, public PIDSource, public LiveWindowSendable
{
public:
    typedef enum {
        kInches = 0,
        kMilliMeters = 1
    } DistanceUnit;
    
    Ultrasonic(DigitalOutput *pingChannel, DigitalInput *echoChannel, DistanceUnit units = kInches);
    Ultrasonic(DigitalOutput &pingChannel, DigitalInput &echoChannel, DistanceUnit units = kInches);
    Ultrasonic(uint32_t pingChannel, uint32_t echoChannel, DistanceUnit units = kInches);
    Ultrasonic(uint8_t pingModuleNumber, uint32_t pingChannel,
                            uint8_t echoModuleNumber, uint32_t echoChannel, DistanceUnit units = kInches);
    virtual ~Ultrasonic();

    void Ping();
    bool IsRangeValid();
    static void SetAutomaticMode(bool enabling);
    double GetRangeInches();
    double GetRangeMM();
    bool IsEnabled() { return m_enabled; }
    void SetEnabled(bool enable) { m_enabled = enable; }
    
    double PIDGet();
    void SetDistanceUnits(DistanceUnit units);
    DistanceUnit GetDistanceUnits();

    void UpdateTable();
    void StartLiveWindowMode();
    void StopLiveWindowMode();
    std::string GetSmartDashboardType();
    void InitTable(ITable *subTable);
    ITable * GetTable();

private:
    void Initialize();

    static void UltrasonicChecker();

    static constexpr double kPingTime = 10 * 1e-6;  
    static const uint32_t kPriority = 90;   
    static constexpr double kMaxUltrasonicTime = 0.1;   
    static constexpr double kSpeedOfSoundInchesPerSec = 1130.0 * 12.0;

    static Task m_task; // task doing the round-robin automatic sensing
    static Ultrasonic *m_firstSensor; // head of the ultrasonic sensor list
    static bool m_automaticEnabled; // automatic round robin mode
    static SEM_ID m_semaphore; // synchronize access to the list of sensors

    DigitalInput *m_echoChannel;
    DigitalOutput *m_pingChannel;
    bool m_allocatedChannels;
    bool m_enabled;
    Counter *m_counter;
    Ultrasonic *m_nextSensor;
    DistanceUnit m_units;
    
    ITable *m_table;
};

#endif