LTC2367-16 - 16-Bit, 500ksps, Pseudo- Differential Unipolar SAR ADC with 94.7dB SNR

/*!
Linear Technology DC1796A Demonstration Board.
LTC2364-16: 16-Bit, 250Ksps ADC.
LTC2364-18: 18-Bit, 250Ksps ADC.
LTC2367-16: 16-Bit, 500Ksps ADC
LTC2367-18: 18-Bit, 500Ksps ADC
LTC2368-16: 16-Bit, 1Msps ADC
LTC2368-18: 18-Bit, 1Msps ADC
LTC2369-18: 18-Bit, 1.6Msps ADC
LTC2370-16: 16-Bit, 2Msps ADC
Max SCK rate is 100MHz.

@verbatim

NOTES
  Setup:
   Set the terminal baud rate to 115200 and select the newline terminator. Equipment
   required is a voltage source (preferably low-noise) and a precision voltmeter.
   Ensure all jumpers on the demo board are installed in their default positions
   from the factory. Refer to Demo Manual DC1796A.

  How to test:
   The voltage source should be connected to input AIN+/AIN-. Ensure the
   input is within its specified absolute input voltage range. (It is easiest
   to tie the voltage source negative terminal to COM.) Ensure the voltage
   source is set within the range of 0V to +4.096V.

USER INPUT DATA FORMAT:
 decimal : 1024
 hex     : 0x400
 octal   : 02000  (leading 0 "zero")
 binary  : B10000000000
 float   : 1024.0

@endverbatim

http://www.linear.com/product/LTC2364-16
http://www.linear.com/product/LTC2364-18
http://www.linear.com/product/LTC2367-16
http://www.linear.com/product/LTC2367-18
http://www.linear.com/product/LTC2368-16
http://www.linear.com/product/LTC2368-18
http://www.linear.com/product/LTC2369-18
http://www.linear.com/product/LTC2370-16

http://www.linear.com/product/LTC2364-16#demoboards
http://www.linear.com/product/LTC2364-18#demoboards
http://www.linear.com/product/LTC2367-16#demoboards
http://www.linear.com/product/LTC2367-18#demoboards
http://www.linear.com/product/LTC2368-16#demoboards
http://www.linear.com/product/LTC2368-18#demoboards
http://www.linear.com/product/LTC2369-18#demoboards
http://www.linear.com/product/LTC2370-16#demoboards

REVISION HISTORY
$Revision: 3659 $
$Date: 2015-07-01 10:19:20 -0700 (Wed, 01 Jul 2015) $

Copyright (c) 2013, Linear Technology Corp.(LTC)
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those
of the authors and should not be interpreted as representing official policies,
either expressed or implied, of Linear Technology Corp.

The Linear Technology Linduino is not affiliated with the official Arduino team.
However, the Linduino is only possible because of the Arduino team's commitment
to the open-source community.  Please, visit http://www.arduino.cc and
http://store.arduino.cc , and consider a purchase that will help fund their
ongoing work.
*/

/*! @file
    @ingroup LTC2370
*/

#include <Arduino.h>
#include <stdint.h>
#include "Linduino.h"
#include "LT_SPI.h"
#include "UserInterface.h"
#include "LT_I2C.h"
#include "QuikEval_EEPROM.h"
#include "LTC2370.h"
#include <SPI.h>
#include <Wire.h>

// Function Declaration
void print_title();                                         // Print the title block
void print_prompt();                                        // Prompt the user for an input command
void print_user_command(uint8_t menu);                      // Display selected differential channels

void menu_1_read_input();
void menu_2_select_bits();

// Global variables
static uint8_t LTC2370_bits = 18;                   //!< Default set for 18 bits
float LTC2370_vref = 4.096;


//! Initialize Linduino
void setup()
{
  uint32_t adc_code;
  quikeval_I2C_init();           // Configure the EEPROM I2C port for 100kHz
  quikeval_SPI_init();           // Configure the spi port for 4MHz SCK
  quikeval_SPI_connect();        // Connect SPI to main data port
  Serial.begin(115200);          // Initialize the serial port to the PC
  print_title();
  print_prompt();
}


//! Repeats Linduino loop
void loop()
{
  uint16_t user_command;
  {
    if (Serial.available())
    {
      user_command = read_int();        // Read the user command
      if (user_command != 'm')
        Serial.println(user_command);   // Prints the user command to com port
      switch (user_command)
      {
        case 1:
          menu_1_read_input();
          break;
        case 2:
          menu_2_select_bits();
          break;
        default:
          Serial.println("Invalid Option");
          break;
      }
      Serial.println();
      print_prompt();
    }
  }
}


// Function Definitions
//! Read channel
//! @return void
void menu_1_read_input()
{
  uint8_t user_command;
  uint32_t adc_code;                           // The LTC2370 code
  int32_t display_code;
  float adc_voltage;                               // The LTC2370 voltage

  // Read and display a selected channel
  LTC2370_read(LTC2370_CS, &adc_code);  //discard the first reading
  delay(100);
  LTC2370_read(LTC2370_CS, &adc_code);

  display_code = adc_code >> (32 - LTC2370_bits);
  if (LTC2370_bits == 16)
    display_code = display_code & 0xFFFF;
  else
    display_code = display_code & 0x3FFFF;

  Serial.print(F("  Received Code: b"));
  Serial.println(display_code, BIN);

  // Convert the received code to voltage
  adc_voltage = LTC2370_code_to_voltage(adc_code, LTC2370_vref);

  Serial.print(F("  Equivalent voltage: "));
  Serial.print(adc_voltage, 4);
  Serial.println(F("V"));
}


//! Select number of bits
//! @return void
void menu_2_select_bits()
{
  uint8_t user_command;

  Serial.println();
  if (LTC2370_bits == 16)
    Serial.println(F("  16 bits selected"));
  else
    Serial.println(F("  18 bits selected"));

  Serial.println(F("  16 = 2370-16"));
  Serial.println(F("  18 = 2370-18"));
  Serial.print(F("  Enter a Command, based upon the resolution of the part under test: "));

  user_command = read_int();    // Read user input
  Serial.println(user_command);   // Prints the user command to com port
  switch (user_command)
  {
    case 16:
      LTC2370_bits = 16;
      Serial.println(F("  16 bits selected"));
      break;
    case 18:
      LTC2370_bits = 18;
      Serial.println(F("  18 bits selected"));
      break;
    default:
      {
        Serial.println("  Invalid Option");
        return;
      }
      break;
  }
}


//! Prints the title block when program first starts.
void print_title()
{
  Serial.println();
  Serial.println(F("*****************************************************************"));
  Serial.println(F("* DC1796A Demonstration Program                                 *"));
  Serial.println(F("*                                                               *"));
  Serial.println(F("* This program demonstrates how to receive data                 *"));
  Serial.println(F("* from the following ADCs:                                      *"));
  Serial.println(F("*   LTC2364-16                                                  *"));
  Serial.println(F("*   LTC2364-18                                                  *"));
  Serial.println(F("*   LTC2367-16                                                  *"));
  Serial.println(F("*   LTC2367-18                                                  *"));
  Serial.println(F("*   LTC2368-16                                                  *"));
  Serial.println(F("*   LTC2368-18                                                  *"));
  Serial.println(F("*   LTC2369-18                                                  *"));
  Serial.println(F("*   LTC2370-16                                                  *"));
  Serial.println(F("*                                                               *"));
  Serial.println(F("* Set the baud rate to 115200 and select the newline terminator.*"));
  Serial.println(F("*                                                               *"));
  Serial.println(F("*****************************************************************"));
}


//! Prints main menu.
void print_prompt()
{
  Serial.println(F("*************************"));
  Serial.println(F("1-Read ADC Input"));
  Serial.println(F("2-Select Number of bits (Default is 18 bits)\n"));
  Serial.print(F("Enter a command:"));
}

/*!
Linear Technology DC1813A Demonstration Board.
LTC2364-16: 16-Bit, 250Ksps ADC.
LTC2364-18: 18-Bit, 250Ksps ADC.
LTC2367-16: 16-Bit, 500Ksps ADC
LTC2367-18: 18-Bit, 500Ksps ADC
LTC2368-16: 16-Bit, 1Msps ADC
LTC2368-18: 18-Bit, 1Msps ADC
LTC2369-18: 18-Bit, 1.6Msps ADC
LTC2370-16: 16-Bit, 2Msps ADC
Max SCK rate is 100MHz.

@verbatim

NOTES
  Setup:
   Set the terminal baud rate to 115200 and select the newline terminator. Equipment
   required is a voltage source (preferably low-noise) and a precision voltmeter.
   Ensure all jumpers on the demo board are installed in their default positions
   from the factory. Refer to Demo Manual DC1813A.

  How to test:
   The voltage source should be connected between inputs AIN+ and AIN-. Ensure both
   inputs are within their specified absolute input voltage range. (It is easiest
   to tie the voltage source negative terminal to COM.) Ensure the voltage
   source is set within the range of 0V to +5V(differential voltage range).
   (Swapping input voltages results in a reversed polarity reading.)

USER INPUT DATA FORMAT:
 decimal : 1024
 hex     : 0x400
 octal   : 02000  (leading 0 "zero")
 binary  : B10000000000
 float   : 1024.0

@endverbatim

http://www.linear.com/product/LTC2364-16
http://www.linear.com/product/LTC2364-18
http://www.linear.com/product/LTC2367-16
http://www.linear.com/product/LTC2367-18
http://www.linear.com/product/LTC2368-16
http://www.linear.com/product/LTC2368-18
http://www.linear.com/product/LTC2369-18
http://www.linear.com/product/LTC2370-16

http://www.linear.com/product/LTC2364-16#demoboards
http://www.linear.com/product/LTC2364-18#demoboards
http://www.linear.com/product/LTC2367-16#demoboards
http://www.linear.com/product/LTC2367-18#demoboards
http://www.linear.com/product/LTC2368-16#demoboards
http://www.linear.com/product/LTC2368-18#demoboards
http://www.linear.com/product/LTC2369-18#demoboards
http://www.linear.com/product/LTC2370-16#demoboards

REVISION HISTORY
$Revision: 3659 $
$Date: 2015-07-01 10:19:20 -0700 (Wed, 01 Jul 2015) $

Copyright (c) 2013, Linear Technology Corp.(LTC)
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those
of the authors and should not be interpreted as representing official policies,
either expressed or implied, of Linear Technology Corp.

The Linear Technology Linduino is not affiliated with the official Arduino team.
However, the Linduino is only possible because of the Arduino team's commitment
to the open-source community.  Please, visit http://www.arduino.cc and
http://store.arduino.cc , and consider a purchase that will help fund their
ongoing work.
*/

/*! @file
    @ingroup LTC2370
*/

#include <Arduino.h>
#include <stdint.h>
#include "Linduino.h"
#include "LT_SPI.h"
#include "UserInterface.h"
#include "LT_I2C.h"
#include "QuikEval_EEPROM.h"
#include "LTC2370.h"
#include <SPI.h>
#include <Wire.h>

// Function Declaration
void print_title();                                         // Print the title block
void print_prompt();                                        // Prompt the user for an input command
void print_user_command(uint8_t menu);                      // Display selected differential channels

void menu_1_read_input();
void menu_2_select_bits();

// Global variables
static uint8_t LTC2370_bits = 18;                   //!< Default set for 18 bits
float LTC2370_vref = 5;


//! Initialize Linduino
void setup()
{
  uint32_t adc_code;
  quikeval_I2C_init();           // Configure the EEPROM I2C port for 100kHz
  quikeval_SPI_init();           // Configure the spi port for 4MHz SCK
  quikeval_SPI_connect();        // Connect SPI to main data port
  Serial.begin(115200);          // Initialize the serial port to the PC
  print_title();
  print_prompt();
}


//! Repeats Linduino loop
void loop()
{
  uint16_t user_command;
  {
    if (Serial.available())
    {
      user_command = read_int();        // Read the user command
      if (user_command != 'm')
        Serial.println(user_command);   // Prints the user command to com port
      switch (user_command)
      {
        case 1:
          menu_1_read_input();
          break;
        case 2:
          menu_2_select_bits();
          break;
        default:
          Serial.println("Invalid Option");
          break;
      }
      Serial.println();
      print_prompt();
    }
  }
}

// Function Definitions
//! Read channel
//! @return void
void menu_1_read_input()
{
  uint8_t user_command;
  uint32_t adc_code;                           // The LTC2370 code
  uint32_t display_code;
  float adc_voltage;                               // The LTC2370 voltage

  // Read and display a selected channel
  LTC2370_read(LTC2370_CS, &adc_code);  //discard the first reading
  delay(100);
  LTC2370_read(LTC2370_CS, &adc_code);

  display_code = adc_code >> (32 - LTC2370_bits);
  if (LTC2370_bits == 16)
    display_code = display_code & 0xFFFF;
  else
    display_code = display_code & 0x3FFFF;

  Serial.print(F("  Received Code: b"));
  Serial.println(display_code, BIN);

  // Convert the received code to voltage
  adc_voltage = LTC2370_code_to_voltage(adc_code, LTC2370_vref);

  Serial.print(F("  Equivalent voltage: "));
  Serial.print(adc_voltage, 4);
  Serial.println(F("V"));
}


//! Select number of bits
//! @return void
void menu_2_select_bits()
{
  uint8_t user_command;

  Serial.println(F("  16 = 23XX-16"));
  Serial.println(F("  18 = 23XX-18"));
  Serial.println(F("  Enter a Command, based upon the resolution of the part under test: "));

  user_command = read_int();    // Read user input
  Serial.println(user_command);   // Prints the user command to com port
  switch (user_command)
  {
    case 16:
      LTC2370_bits = 16;
      Serial.println(F("  16 bits selected"));
      break;
    case 18:
      LTC2370_bits = 18;
      Serial.println(F("  18 bits selected"));
      break;
    default:
      {
        Serial.println("  Invalid Option");
        return;
      }
      break;
  }
}


//! Prints the title block when program first starts.
void print_title()
{
  Serial.println();
  Serial.println(F("*****************************************************************"));
  Serial.println(F("* DC1813A Demonstration Program                                 *"));
  Serial.println(F("*                                                               *"));
  Serial.println(F("* This program demonstrates how to receive data                 *"));
  Serial.println(F("* from the following ADCs:                                      *"));
  Serial.println(F("*   LTC2364-16                                                  *"));
  Serial.println(F("*   LTC2364-18                                                  *"));
  Serial.println(F("*   LTC2367-16                                                  *"));
  Serial.println(F("*   LTC2367-18                                                  *"));
  Serial.println(F("*   LTC2368-16                                                  *"));
  Serial.println(F("*   LTC2368-18                                                  *"));
  Serial.println(F("*   LTC2369-18                                                  *"));
  Serial.println(F("*   LTC2370-16                                                  *"));
  Serial.println(F("*                                                               *"));
  Serial.println(F("* Set the baud rate to 115200 and select the newline terminator.*"));
  Serial.println(F("*                                                               *"));
  Serial.println(F("*****************************************************************"));
}


//! Prints main menu.
void print_prompt()
{
  Serial.println(F("*************************"));
  Serial.println(F("1-Read ADC Input"));
  Serial.println(F("2-Select Number of bits (Default is 18 bits)\n"));
  Serial.print(F("Enter a command:"));
}

/*!
LTC2364-16: 16-Bit, 250Ksps ADC.
LTC2364-18: 18-Bit, 250Ksps ADC.
LTC2367-16: 16-Bit, 500Ksps ADC
LTC2367-18: 18-Bit, 500Ksps ADC
LTC2368-16: 16-Bit, 1Msps ADC
LTC2368-18: 18-Bit, 1Msps ADC
LTC2369-18: 18-Bit, 1.6Msps ADC
LTC2370-16: 16-Bit, 2Msps ADC

@verbatim

The following parts (DUT) are pin-compatible, 16/18-bit A/D converters with serial I/O, and an internal reference:
LTC2364-16: 16-Bit, 250Ksps ADC
LTC2364-18: 18-Bit, 250Ksps ADC
LTC2367-16: 16-Bit, 500Ksps ADC
LTC2367-18: 18-Bit, 500Ksps ADC
LTC2368-16: 16-Bit, 1Msps ADC
LTC23678-18: 18-Bit, 1Msps ADC
LTC2369-18: 18-Bit, 1.6Msps ADC
LTC2370-16: 16-Bit, 2Msps ADC

Example Code:

Read ADC input.

    LTC2370_read(LTC2370_CS, &adc_code);   // Throws out last reading
    LTC2370_read(LTC2370_CS, &adc_code);   // Obtains the current reading and stores to adc_code variable

    // Convert adc_code to voltage
    adc_voltage = LTC2370_code_to_voltage(adc_code, vref);

@endverbatim

http://www.linear.com/product/LTC2364-16
http://www.linear.com/product/LTC2364-18
http://www.linear.com/product/LTC2367-16
http://www.linear.com/product/LTC2367-18
http://www.linear.com/product/LTC2368-16
http://www.linear.com/product/LTC2368-18
http://www.linear.com/product/LTC2369-18
http://www.linear.com/product/LTC2370-16

http://www.linear.com/product/LTC2364-16#demoboards
http://www.linear.com/product/LTC2364-18#demoboards
http://www.linear.com/product/LTC2367-16#demoboards
http://www.linear.com/product/LTC2367-18#demoboards
http://www.linear.com/product/LTC2368-16#demoboards
http://www.linear.com/product/LTC2368-18#demoboards
http://www.linear.com/product/LTC2369-18#demoboards
http://www.linear.com/product/LTC2370-16#demoboards

REVISION HISTORY
$Revision: 3659 $
$Date: 2015-07-01 10:19:20 -0700 (Wed, 01 Jul 2015) $

Copyright (c) 2013, Linear Technology Corp.(LTC)
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those
of the authors and should not be interpreted as representing official policies,
either expressed or implied, of Linear Technology Corp.

The Linear Technology Linduino is not affiliated with the official Arduino team.
However, the Linduino is only possible because of the Arduino team's commitment
to the open-source community.  Please, visit http://www.arduino.cc and
http://store.arduino.cc , and consider a purchase that will help fund their
ongoing work.
*/

/*! @file
    @ingroup LTC2370
    Header for LTC2370: 16/18-bit 1Msps ADC
*/

#ifndef LTC2370_H
#define LTC2370_H

#include <SPI.h>

//! Define the SPI CS pin
#ifndef LTC2370_CS
#define LTC2370_CS QUIKEVAL_CS
#endif

//! @name LTC2370 Channel Address
//! @{
// Channel Address
#define LTC2370_ADDRESS             0x00
//!@}


//! Reads the LTC2370 and returns 32-bit data in offset binary format
//! @return void
void LTC2370_read(uint8_t cs,           //!< Chip Select Pin
                  uint32_t *ptr_adc_code    //!< Returns code read from ADC (from previous conversion)
                 );


//! Calculates the LTC2370 input voltage given the binary data and lsb weight.
//! @return Floating point voltage
float LTC2370_code_to_voltage(uint32_t adc_code,                   //!< Raw ADC code
                              float vref              //!< Reference voltage
                             );

#endif  //  LTC2370_H

/*!
LTC2364-16: 16-Bit, 250Ksps ADC.
LTC2364-18: 18-Bit, 250Ksps ADC.
LTC2367-16: 16-Bit, 500Ksps ADC
LTC2367-18: 18-Bit, 500Ksps ADC
LTC2368-16: 16-Bit, 1Msps ADC
LTC2368-18: 18-Bit, 1Msps ADC
LTC2369-18: 18-Bit, 1.6Msps ADC
LTC2370-16: 16-Bit, 2Msps ADC

@verbatim

The following parts (DUT) are pin-compatible, 16/18-bit A/D converters with serial I/O, and an internal reference:
LTC2364-16: 16-Bit, 250Ksps ADC
LTC2364-18: 18-Bit, 250Ksps ADC
LTC2367-16: 16-Bit, 500Ksps ADC
LTC2367-18: 18-Bit, 500Ksps ADC
LTC2368-16: 16-Bit, 1Msps ADC
LTC23678-18: 18-Bit, 1Msps ADC
LTC2369-18: 18-Bit, 1.6Msps ADC
LTC2370-16: 16-Bit, 2Msps ADC

@endverbatim

http://www.linear.com/product/LTC2364-16
http://www.linear.com/product/LTC2364-18
http://www.linear.com/product/LTC2367-16
http://www.linear.com/product/LTC2367-18
http://www.linear.com/product/LTC2368-16
http://www.linear.com/product/LTC2368-18
http://www.linear.com/product/LTC2369-18
http://www.linear.com/product/LTC2370-16

http://www.linear.com/product/LTC2364-16#demoboards
http://www.linear.com/product/LTC2364-18#demoboards
http://www.linear.com/product/LTC2367-16#demoboards
http://www.linear.com/product/LTC2367-18#demoboards
http://www.linear.com/product/LTC2368-16#demoboards
http://www.linear.com/product/LTC2368-18#demoboards
http://www.linear.com/product/LTC2369-18#demoboards
http://www.linear.com/product/LTC2370-16#demoboards

REVISION HISTORY
$Revision: 6237 $
$Date: 2016-12-20 15:09:16 -0800 (Tue, 20 Dec 2016) $

Copyright (c) 2013, Linear Technology Corp.(LTC)
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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The Linear Technology Linduino is not affiliated with the official Arduino team.
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*/

//! @ingroup Analog_to_Digital_Converters
//! @{
//! @defgroup LTC2370 LTC2370: 16/18-Bit 1Msps ADC
//! @}

/*! @file
    @ingroup LTC2370
    Library for LTC2370: 16/18-Bit 1Msps ADC
*/

#include <Arduino.h>
#include <stdint.h>
#include "Linduino.h"
#include "LT_SPI.h"
#include "LTC2370.h"
#include <SPI.h>


// Reads from a SPI LTC2370-XX device that has no configuration word and a 20 bit output word in offset binary format.
void LTC2370_read(uint8_t cs, uint32_t *ptr_adc_code)
{
  LT_union_int16_2bytes command;    // LTC2370 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 offset binary, given the reference voltage (in volts)
float LTC2370_code_to_voltage(uint32_t adc_code, float vref)
{
  float voltage;

  voltage = (float)adc_code;
  voltage = voltage / (pow(2,32)-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);
}