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// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
#pragma once
#include <wpi/sendable/Sendable.h>
#include <wpi/sendable/SendableHelper.h>
#include "frc/DigitalSource.h"
namespace frc {
class AnalogTrigger;
/**
* Class to represent a specific output from an analog trigger.
*
* This class is used to get the current output value and also as a
* DigitalSource to provide routing of an output to digital subsystems on the
* FPGA such as Counter, Encoder, and Interrupt.
*
* The TriggerState output indicates the primary output value of the trigger.
* If the analog signal is less than the lower limit, the output is false. If
* the analog value is greater than the upper limit, then the output is true.
* If the analog value is in between, then the trigger output state maintains
* its most recent value.
*
* The InWindow output indicates whether or not the analog signal is inside the
* range defined by the limits.
*
* The RisingPulse and FallingPulse outputs detect an instantaneous transition
* from above the upper limit to below the lower limit, and vice versa. These
* pulses represent a rollover condition of a sensor and can be routed to an up
* / down counter or to interrupts. Because the outputs generate a pulse, they
* cannot be read directly. To help ensure that a rollover condition is not
* missed, there is an average rejection filter available that operates on the
* upper 8 bits of a 12 bit number and selects the nearest outlier of 3 samples.
* This will reject a sample that is (due to averaging or sampling) errantly
* between the two limits. This filter will fail if more than one sample in a
* row is errantly in between the two limits. You may see this problem if
* attempting to use this feature with a mechanical rollover sensor, such as a
* 360 degree no-stop potentiometer without signal conditioning, because the
* rollover transition is not sharp / clean enough. Using the averaging engine
* may help with this, but rotational speeds of the sensor will then be limited.
*/
class AnalogTriggerOutput : public DigitalSource,
public wpi::Sendable,
public wpi::SendableHelper<AnalogTriggerOutput> {
friend class AnalogTrigger;
public:
/**
* Get the state of the analog trigger output.
*
* @return The state of the analog trigger output.
*/
bool Get() const;
// DigitalSource interface
/**
* @return The HAL Handle to the specified source.
*/
HAL_Handle GetPortHandleForRouting() const override;
/**
* @return The type of analog trigger output to be used.
*/
AnalogTriggerType GetAnalogTriggerTypeForRouting() const override;
/**
* Is source an AnalogTrigger
*/
bool IsAnalogTrigger() const override;
/**
* @return The channel of the source.
*/
int GetChannel() const override;
void InitSendable(wpi::SendableBuilder& builder) override;
protected:
/**
* Create an object that represents one of the four outputs from an analog
* trigger.
*
* Because this class derives from DigitalSource, it can be passed into
* routing functions for Counter, Encoder, etc.
*
* @param trigger A pointer to the trigger for which this is an output.
* @param outputType An enum that specifies the output on the trigger to
* represent.
*/
AnalogTriggerOutput(const AnalogTrigger& trigger,
AnalogTriggerType outputType);
private:
// Uses pointer rather than smart pointer because a user can not construct
// an AnalogTriggerOutput themselves and because the AnalogTriggerOutput
// should always be in scope at the same time as an AnalogTrigger.
const AnalogTrigger* m_trigger;
AnalogTriggerType m_outputType;
};
} // namespace frc