hal/lib/athena/AnalogOutput.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2016-2017. 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/AnalogOutput.h"

#include "AnalogInternal.h"
#include "HAL/Errors.h"
#include "HAL/handles/HandlesInternal.h"
#include "HAL/handles/IndexedHandleResource.h"
#include "PortsInternal.h"

using namespace hal;

namespace {
struct AnalogOutput {
  uint8_t channel;
};
}

static IndexedHandleResource<HAL_AnalogOutputHandle, AnalogOutput,
                             kNumAnalogOutputs, HAL_HandleEnum::AnalogOutput>
    analogOutputHandles;

extern "C" {

/**
 * Initialize the analog output port using the given port object.
 */
HAL_AnalogOutputHandle HAL_InitializeAnalogOutputPort(HAL_PortHandle portHandle,
                                                      int32_t* status) {
  initializeAnalog(status);

  if (*status != 0) return HAL_kInvalidHandle;

  int16_t channel = getPortHandleChannel(portHandle);
  if (channel == InvalidHandleIndex) {
    *status = PARAMETER_OUT_OF_RANGE;
    return HAL_kInvalidHandle;
  }

  HAL_AnalogOutputHandle handle = analogOutputHandles.Allocate(channel, status);

  if (*status != 0)
    return HAL_kInvalidHandle;  // failed to allocate. Pass error back.

  auto port = analogOutputHandles.Get(handle);
  if (port == nullptr) {  // would only error on thread issue
    *status = HAL_HANDLE_ERROR;
    return HAL_kInvalidHandle;
  }

  port->channel = static_cast<uint8_t>(channel);
  return handle;
}

void HAL_FreeAnalogOutputPort(HAL_AnalogOutputHandle analogOutputHandle) {
  // no status, so no need to check for a proper free.
  analogOutputHandles.Free(analogOutputHandle);
}

/**
 * Check that the analog output channel number is value.
 * Verify that the analog channel number is one of the legal channel numbers.
 * Channel numbers are 0-based.
 *
 * @return Analog channel is valid
 */
HAL_Bool HAL_CheckAnalogOutputChannel(int32_t channel) {
  return channel < kNumAnalogOutputs && channel >= 0;
}

void HAL_SetAnalogOutput(HAL_AnalogOutputHandle analogOutputHandle,
                         double voltage, int32_t* status) {
  auto port = analogOutputHandles.Get(analogOutputHandle);
  if (port == nullptr) {
    *status = HAL_HANDLE_ERROR;
    return;
  }

  uint16_t rawValue = static_cast<uint16_t>(voltage / 5.0 * 0x1000);

  if (voltage < 0.0)
    rawValue = 0;
  else if (voltage > 5.0)
    rawValue = 0x1000;

  analogOutputSystem->writeMXP(port->channel, rawValue, status);
}

double HAL_GetAnalogOutput(HAL_AnalogOutputHandle analogOutputHandle,
                           int32_t* status) {
  auto port = analogOutputHandles.Get(analogOutputHandle);
  if (port == nullptr) {
    *status = HAL_HANDLE_ERROR;
    return 0.0;
  }

  uint16_t rawValue = analogOutputSystem->readMXP(port->channel, status);

  return rawValue * 5.0 / 0x1000;
}
}