adc_driver.cpp

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//\Author Kai Franke, Robert Bosch LLC

#include "adc_driver/adc_driver.h"

AdcDriver::AdcDriver( bosch_hardware_interface* hw, uint8_t adc_pin ): sensor_driver( hw )
{
  _pin = adc_pin;
}

AdcDriver::~AdcDriver()
{
}

uint8_t AdcDriver::getDeviceAddress()
{
  // the answer to all questions +5
  return 47;
}

bool AdcDriver::initialize()
{  
  // Initialize the hardware interface
  if( hardware_->initialize() == false )
  {
    ROS_ERROR("AdcDriver::initialize(): Could not initialize a hardware interface!");
    return false;
  }
  return true;
}

uint32_t AdcDriver::read(  )
{
  int *flags = NULL; //not needed 
  int frequency = 0; // does not apply for ADC
  uint8_t num_bytes = 4;
  uint8_t data[4];
  
  if( hardware_->read( this->getDeviceAddress(), ADCONVERTER, frequency, flags, _pin, data, num_bytes ) < 0 )
  {
    ROS_ERROR("AdcDriver::read(): could not read input");
    return 0;
  } 
  // convert read data to float
  uint32_t temp[4];
  uint32_t adc_uV;
  temp[0] = data[0];
  temp[1] = data[1];
  temp[2] = data[2];
  temp[3] = data[3];
  adc_uV  = (temp[0] << 24) + (temp[1] << 16) + (temp[2] << 8) + temp[3] ;
  
  /* the following code would allow returning the voltage as a float but is most likely not very portable because of the reinterpret cast
  return *reinterpret_cast<float *>( &adc_uV );
  */
  return adc_uV;
}

bool AdcDriver::setReference( uint32_t voltage )
{
  int *flags = NULL; //not needed 
  int frequency = 0; // does not apply for ADC
  uint8_t reg = 0; // not needed
  uint8_t num_bytes = 4;
  uint8_t voltage_chopped[4];
  
  // write expects an uint_8 array, chopping uint32 to four uint8_t MSB first
  uint32_t temp;
  temp = (voltage & (0xFF << 24)) >> 24;
  voltage_chopped[0] = (uint8_t)temp;
  temp = (voltage & (0xFF << 16)) >> 16;
  voltage_chopped[1] = (uint8_t)temp;
  temp = (voltage & (0xFF << 8)) >> 8;
  voltage_chopped[2] = (uint8_t)temp;
  temp = (voltage & (0xFF << 0));
  voltage_chopped[3] = (uint8_t)temp;
  
  if( hardware_->write( this->getDeviceAddress(), ADCONVERTER, frequency, flags, reg, voltage_chopped, num_bytes ) < 0 )
  {
    ROS_ERROR("AdcDriver::setReference(): could not write reference voltage");
    return false;
  } 
  return true;
}