/*!
LTC2637: Octal 12-/10-/8-Bit I2C VOUT DACs with 10ppm/°C Reference.
LTC2635: Quad 12-/10-/8-Bit I2C VOUT DACs with 10ppm/°C Reference.

@verbatim

The LTC2637 is a family of octal I2C 16-/12-Bit Rail-to-Rail DACs with
Integrated 10ppm/C Max Reference. The DACs have built-in high performance,
rail-to-rail, output buffers and are guaranteed monotonic. The LTC2637-L has a
full-scale output of 2.5V with the integrated reference and operates from a
single 2.7V to 5.5V supply. The LTC2637-H has a full-scale output of 4.096V with
the integrated reference and operates from a 4.5V to 5.5V supply. Each DAC can
also operate with an external reference, which sets the full-scale output to 2
times the external reference voltage.

The parts use a 2-wire I2C compatible serial interface. The LTC2637 operates in
both the standard mode (maximum clock rate of 100kHz) and the fast mode (maximum
clock rate of 400kHz). The LTC2637 incorporates a power-on reset circuit that is
controlled by the PORSEL pin. If PORSEL is tied to GND the DACs reset to
zero-scale at power-up. If PORSEL is tied to VCC, the DACs reset to mid-scale at
power-up.

@endverbatim

http://www.linear.com/product/LTC2637

http://www.linear.com/product/LTC2635

http://www.linear.com/product/LTC2637#demoboards

http://www.linear.com/product/LTC2635#demoboards


Copyright 2018(c) Analog Devices, Inc.

All rights reserved.

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   notice, this list of conditions and the following disclaimer in
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 - Neither the name of Analog Devices, Inc. nor the names of its
   contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.
 - The use of this software may or may not infringe the patent rights
   of one or more patent holders.  This license does not release you
   from the requirement that you obtain separate licenses from these
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 - Use of the software either in source or binary form, must be run
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THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
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*/

//! @ingroup Digital_to_Analog_Converters
//! @{
//! @defgroup LTC2637 LTC2637: Octal 12-/10-/8-Bit I2C VOUT DACs with 10ppm/°C Reference
//! @}

/*! @file
    @ingroup LTC2637
    Library for LTC2637 Octal 12-/10-/8-Bit I2C VOUT DACs with 10ppm/°C Reference
*/

#include <Arduino.h>
#include <stdint.h>
#include <math.h>
#include "Linduino.h"
#include "LT_I2C.h"
#include "LTC2637.h"

// Write a 16-bit dac_code to the LTC2637.
// The function returns the state of the acknowledge bit after the I2C address write. 0=acknowledge, 1=no acknowledge.
int8_t LTC2637_write(uint8_t i2c_address, uint8_t dac_command, uint8_t dac_address, uint16_t dac_code)
{
  int8_t ack;

  ack = i2c_write_word_data(i2c_address, dac_command | dac_address, dac_code);
  return(ack);
}

// Calculate a LTC2637 DAC code given the desired output voltage and DAC address (0-7)
uint16_t LTC2637_voltage_to_code(float dac_voltage, float LTC2637_lsb, int16_t LTC2637_offset)
{
  int32_t dac_code;
  float float_code;
  float_code = dac_voltage / LTC2637_lsb;                                                             //! 1) Calculate the DAC code
  float_code = (float_code > (floor(float_code) + 0.5)) ? ceil(float_code) : floor(float_code);       //! 2) Round
  dac_code = (int32_t)float_code - LTC2637_offset;                                                    //! 3) Subtract offset
  if (dac_code < 0)                                                                                   //! 4) If DAC code < 0, Then DAC code = 0
    dac_code = 0;
  return ((uint16_t)dac_code);                                                                        //! 5) Cast DAC code as uint16_t
}

// Calculate the LTC2637 DAC output voltage given the DAC code and DAC address (0-7)
float LTC2637_code_to_voltage(uint16_t dac_code, float LTC2637_lsb, int16_t LTC2637_offset)
{
  float dac_voltage;
  dac_voltage = ((float)(dac_code + LTC2637_offset)* LTC2637_lsb);                                    //! 1) Calculates the dac_voltage
  return (dac_voltage);
}

// Calculate the LTC2637 offset and LSB voltage given two measured voltages and their corresponding codes
void LTC2637_calibrate(uint16_t dac_code1, uint16_t dac_code2, float voltage1, float voltage2, float *LTC2637_lsb, int16_t *LTC2637_offset)
{
  float temp_offset;
  *LTC2637_lsb = (voltage2 - voltage1) / ((float) (dac_code2 - dac_code1));                           //! 1) Calculate the LSB
  temp_offset = voltage1/(*LTC2637_lsb) - (float)dac_code1;                                           //! 2) Calculate the offset
  temp_offset = (temp_offset > (floor(temp_offset) + 0.5)) ? ceil(temp_offset) : floor(temp_offset);  //! 3) Round offset
  *LTC2637_offset = (int16_t)temp_offset;                                                             //! 4) Cast as int16_t
}