/*!
LTC2326-16: 16-Bit, 250ksps Pseudo-differential input ADC.
LTC2326-18: 18-Bit, 250ksps Pseudo-differential input ADC.
LTC2327-16: 16-Bit, 500ksps Pseudo-differential input ADC
LTC2327-18: 18-Bit, 500ksps Pseudo-differential input ADC
LTC2328-16: 16-Bit, 1Msps Pseudo-differential input ADC
LTC2328-18: 18-Bit, 1Msps Pseudo-differential input ADC
LTC2336-18: 18-Bit, 250ksps Fully-differential input ADC
LTC2337-18: 18-Bit, 500ksps Fully-differential ADC
LTC2338-18: 18-Bit, 1Msps Fully-differential input ADC

@verbatim

The following parts (DUT) are pin-compatible, 16/18-bit A/D converters with serial I/O, and an internal reference:
LTC2326-16: 16-Bit, 250ksps Pseudo-differential input ADC.
LTC2326-18: 18-Bit, 250ksps Pseudo-differential input ADC.
LTC2327-16: 16-Bit, 500ksps Pseudo-differential input ADC
LTC2327-18: 18-Bit, 500ksps Pseudo-differential input ADC
LTC2328-16: 16-Bit, 1Msps Pseudo-differential input ADC
LTC2328-18: 18-Bit, 1Msps Pseudo-differential input ADC
LTC2336-18: 18-Bit, 250ksps Fully-differential input ADC
LTC2337-18: 18-Bit, 500ksps Fully-differential ADC
LTC2338-18: 18-Bit, 1Msps Fully-differential input ADC

@endverbatim

http://www.linear.com/product/LTC2326-16
http://www.linear.com/product/LTC2326-18
http://www.linear.com/product/LTC2327-16
http://www.linear.com/product/LTC2327-18
http://www.linear.com/product/LTC2328-16
http://www.linear.com/product/LTC2328-18
http://www.linear.com/product/LTC2336-18
http://www.linear.com/product/LTC2337-18
http://www.linear.com/product/LTC2338-18

http://www.linear.com/product/LTC2326-16#demoboards
http://www.linear.com/product/LTC2326-18#demoboards
http://www.linear.com/product/LTC2327-16#demoboards
http://www.linear.com/product/LTC2327-18#demoboards
http://www.linear.com/product/LTC2328-16#demoboards
http://www.linear.com/product/LTC2328-18#demoboards
http://www.linear.com/product/LTC2336-18#demoboards
http://www.linear.com/product/LTC2337-18#demoboards
http://www.linear.com/product/LTC2338-18#demoboards


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*/

//! @ingroup Analog_to_Digital_Converters
//! @{
//! @defgroup LTC2338 LTC2338: 16/18-Bit 1Msps ADC
//! @}

/*! @file
    @ingroup LTC2338
    Library for LTC2338: 16/18-Bit 1Msps ADC
*/

#include <Arduino.h>
#include <stdint.h>
#include "Linduino.h"
#include "LT_SPI.h"
#include "LTC2338.h"
#include <SPI.h>


// Reads from a SPI LTC2338-XX device that has no configuration word and a 20 bit output word in 2's complement format.
void LTC2338_read(uint8_t cs, int32_t *ptr_adc_code)
{
  LT_union_int16_2bytes command;    // LTC2338 data and command
  command.LT_uint16 = 0;                // Set to zero, not necessary but avoids
  // random data in scope shots.

//Form a four byte object to hold four bytes of data
  LT_union_int32_4bytes data; //instantiate the union
  data.LT_byte[3] = 0;
  data.LT_byte[2] = 0;
  data.LT_byte[1] = 0;
  data.LT_byte[0] = 0;

  spi_transfer_block(cs,command.LT_byte,data.LT_byte,4);

  *ptr_adc_code = data.LT_int32;

  return;
}


// Calculates the voltage corresponding to an adc code in 2's complement, given the reference voltage (in volts)
float LTC2338_code_to_voltage(int32_t adc_code, float vref)
{
  float voltage;

  voltage = (float)adc_code;
  voltage = voltage / (pow(2,31)-1);    //! 2) This calculates the input as a fraction of the reference voltage (dimensionless)
  voltage = voltage * vref;           //! 3) Multiply fraction by Vref to get the actual voltage at the input (in volts)

  return(voltage);
}
