frc971/wpilib/ahal/Relay.cc

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2008-2017. 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 the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#include "hal/Relay.h"

#include <sstream>

#include "frc971/wpilib/ahal/Relay.h"
#include "frc971/wpilib/ahal/WPIErrors.h"
#include "hal/HAL.h"
#include "hal/Ports.h"

using namespace frc;

/**
 * Relay constructor given a channel.
 *
 * This code initializes the relay and reserves all resources that need to be
 * locked. Initially the relay is set to both lines at 0v.
 *
 * @param channel   The channel number (0-3).
 * @param direction The direction that the Relay object will control.
 */
Relay::Relay(int channel, Relay::Direction direction)
    : m_channel(channel), m_direction(direction) {
  std::stringstream buf;
  if (!CheckRelayChannel(m_channel)) {
    buf << "Relay Channel " << m_channel;
    wpi_setWPIErrorWithContext(ChannelIndexOutOfRange, buf.str());
    return;
  }

  HAL_PortHandle portHandle = HAL_GetPort(channel);

  if (m_direction == kBothDirections || m_direction == kForwardOnly) {
    int32_t status = 0;
    m_forwardHandle =
        HAL_InitializeRelayPort(portHandle, true, nullptr, &status);
    if (status != 0) {
      wpi_setErrorWithContextRange(status, 0, HAL_GetNumRelayChannels(),
                                   channel, HAL_GetErrorMessage(status));
      m_forwardHandle = HAL_kInvalidHandle;
      m_reverseHandle = HAL_kInvalidHandle;
      return;
    }
    HAL_Report(HALUsageReporting::kResourceType_Relay, m_channel);
  }
  if (m_direction == kBothDirections || m_direction == kReverseOnly) {
    int32_t status = 0;
    m_reverseHandle =
        HAL_InitializeRelayPort(portHandle, false, nullptr, &status);
    if (status != 0) {
      wpi_setErrorWithContextRange(status, 0, HAL_GetNumRelayChannels(),
                                   channel, HAL_GetErrorMessage(status));
      m_forwardHandle = HAL_kInvalidHandle;
      m_reverseHandle = HAL_kInvalidHandle;
      return;
    }

    HAL_Report(HALUsageReporting::kResourceType_Relay, m_channel + 128);
  }

  int32_t status = 0;
  if (m_forwardHandle != HAL_kInvalidHandle) {
    HAL_SetRelay(m_forwardHandle, false, &status);
    if (status != 0) {
      wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
      m_forwardHandle = HAL_kInvalidHandle;
      m_reverseHandle = HAL_kInvalidHandle;
      return;
    }
  }
  if (m_reverseHandle != HAL_kInvalidHandle) {
    HAL_SetRelay(m_reverseHandle, false, &status);
    if (status != 0) {
      wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
      m_forwardHandle = HAL_kInvalidHandle;
      m_reverseHandle = HAL_kInvalidHandle;
      return;
    }
  }
}

/**
 * Free the resource associated with a relay.
 *
 * The relay channels are set to free and the relay output is turned off.
 */
Relay::~Relay() {
  int32_t status = 0;
  HAL_SetRelay(m_forwardHandle, false, &status);
  HAL_SetRelay(m_reverseHandle, false, &status);
  // ignore errors, as we want to make sure a free happens.
  if (m_forwardHandle != HAL_kInvalidHandle) HAL_FreeRelayPort(m_forwardHandle);
  if (m_reverseHandle != HAL_kInvalidHandle) HAL_FreeRelayPort(m_reverseHandle);
}

/**
 * Set the relay state.
 *
 * Valid values depend on which directions of the relay are controlled by the
 * object.
 *
 * When set to kBothDirections, the relay can be any of the four states:
 * 0v-0v, 0v-12v, 12v-0v, 12v-12v
 *
 * When set to kForwardOnly or kReverseOnly, you can specify the constant for
 * the direction or you can simply specify kOff and kOn.  Using only kOff and
 * kOn is recommended.
 *
 * @param value The state to set the relay.
 */
void Relay::Set(Relay::Value value) {
  if (StatusIsFatal()) return;

  int32_t status = 0;

  switch (value) {
    case kOff:
      if (m_direction == kBothDirections || m_direction == kForwardOnly) {
        HAL_SetRelay(m_forwardHandle, false, &status);
      }
      if (m_direction == kBothDirections || m_direction == kReverseOnly) {
        HAL_SetRelay(m_reverseHandle, false, &status);
      }
      break;
    case kOn:
      if (m_direction == kBothDirections || m_direction == kForwardOnly) {
        HAL_SetRelay(m_forwardHandle, true, &status);
      }
      if (m_direction == kBothDirections || m_direction == kReverseOnly) {
        HAL_SetRelay(m_reverseHandle, true, &status);
      }
      break;
    case kForward:
      if (m_direction == kReverseOnly) {
        wpi_setWPIError(IncompatibleMode);
        break;
      }
      if (m_direction == kBothDirections || m_direction == kForwardOnly) {
        HAL_SetRelay(m_forwardHandle, true, &status);
      }
      if (m_direction == kBothDirections) {
        HAL_SetRelay(m_reverseHandle, false, &status);
      }
      break;
    case kReverse:
      if (m_direction == kForwardOnly) {
        wpi_setWPIError(IncompatibleMode);
        break;
      }
      if (m_direction == kBothDirections) {
        HAL_SetRelay(m_forwardHandle, false, &status);
      }
      if (m_direction == kBothDirections || m_direction == kReverseOnly) {
        HAL_SetRelay(m_reverseHandle, true, &status);
      }
      break;
  }

  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

/**
 * Get the Relay State
 *
 * Gets the current state of the relay.
 *
 * When set to kForwardOnly or kReverseOnly, value is returned as kOn/kOff not
 * kForward/kReverse (per the recommendation in Set)
 *
 * @return The current state of the relay as a Relay::Value
 */
Relay::Value Relay::Get() const {
  int32_t status;

  if (HAL_GetRelay(m_forwardHandle, &status)) {
    if (HAL_GetRelay(m_reverseHandle, &status)) {
      return kOn;
    } else {
      if (m_direction == kForwardOnly) {
        return kOn;
      } else {
        return kForward;
      }
    }
  } else {
    if (HAL_GetRelay(m_reverseHandle, &status)) {
      if (m_direction == kReverseOnly) {
        return kOn;
      } else {
        return kReverse;
      }
    } else {
      return kOff;
    }
  }

  wpi_setErrorWithContext(status, HAL_GetErrorMessage(status));
}

int Relay::GetChannel() const { return m_channel; }