/*!
LTC2990: 14-bit Quad I2C Voltage, Current, and Temperature Monitor

@verbatim

The LTC2990 is used to monitor system temperatures, voltages and currents.
Through the I2C serial interface, the four monitors can individually measure
supply voltages and can be paired for differential measurements of current sense
resistors or temperature sensing transistors. Additional measurements include
internal temperature and internal VCC. The internal 10ppm reference minimizes
the number of supporting components and area required. Selectable address and
configurable functionality give the LTC2990 flexibility to be incorporated in
various systems needing temperature, voltage or current data. The LTC2990 fits
well in systems needing sub-millivolt voltage resolution, 1% current measurement
and 1 degree Celsius temperature accuracy or any combination of the three.

@endverbatim

http://www.linear.com/product/LTC2990

http://www.linear.com/product/LTC2990#demoboards


Copyright 2018(c) Analog Devices, Inc.

All rights reserved.

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   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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   on or directly connected to an Analog Devices Inc. component.

THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
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*/

//! @ingroup Power_Monitors
//! @{
//! @defgroup LTC2990 LTC2990: 14-bit Quad I2C Voltage, Current, and Temperature Monitor
//! @}

/*! @file
    @ingroup LTC2990
    Library for LTC2990: 14-bit Quad I2C Voltage, Current, and Temperature Monitor
*/

#include <Arduino.h>
#include <stdint.h>
#include "Linduino.h"
#include "LT_I2C.h"
#include "LTC2990.h"
#include <Wire.h>

// Reads a 14-bit adc_code from LTC2990.
int8_t LTC2990_adc_read(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid)
{
  int8_t ack = 0;
  uint16_t code;
  ack = i2c_read_word_data(i2c_address, msb_register_address, &code);

  *data_valid = (code >> 15) & 0x01;   // Place Data Valid Bit in *data_valid

  *adc_code = code & 0x7FFF;  // Removes data valid bit to return proper adc_code value

  return(ack);
}

// Reads a 14-bit adc_code from the LTC2990 but enforces a maximum timeout.
// Similar to LTC2990_adc_read except it repeats until the data_valid bit is set, it fails to receive an I2C acknowledge, or the timeout (in milliseconds)
// expires. It keeps trying to read from the LTC2990 every millisecond until the data_valid bit is set (indicating new data since the previous
// time this register was read) or until it fails to receive an I2C acknowledge (indicating an error on the I2C bus).
int8_t LTC2990_adc_read_timeout(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid, uint16_t timeout, uint8_t status_bit)
{
  int8_t ack = 0;
  uint8_t reg_data;
  uint16_t timer_count;  // Timer count for data_valid
  *data_valid = 0;

  for (timer_count = 0; timer_count < timeout; timer_count++)
  {

    ack |=  LTC2990_register_read(i2c_address, LTC2990_STATUS_REG, &reg_data); //! 1)Read status register until correct data valid bit is set

    if ((ack) || (((reg_data>>status_bit)&0x1)==1))
    {
      break;
    }
    delay(1);
  }
  ack |= LTC2990_adc_read(i2c_address, msb_register_address, &(*adc_code), &(*data_valid));   //! 2) It's either valid or it's timed out, we read anyways
  if (*data_valid  !=1)
  {
    return (1);
  }
  return(ack);
}

// Reads new data (even after a mode change) by flushing old data and waiting for the data_valid bit to be set.
// This function simplifies adc reads when modes are changing.  For example, if V1-V2 changes from temperature mode
// to differential voltage mode, the data in the register may still correspond to the temperature reading immediately
// after the mode change.  Flushing one reading and waiting for a new reading guarantees fresh data is received.
// If the timeout is reached without valid data (*data_valid=1) the function exits.
int8_t LTC2990_adc_read_new_data(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid, uint16_t timeout)
{
  int8_t ack = 0;
  uint8_t status_bit;
  status_bit  = msb_register_address/2-1;
  ack |= LTC2990_adc_read_timeout(i2c_address, msb_register_address, adc_code, data_valid, timeout, status_bit); //! 1)  Throw away old data

  ack |= LTC2990_adc_read_timeout(i2c_address, msb_register_address, adc_code, data_valid, timeout,status_bit); //! 2) Read new data

  return(ack);
}

// Reads an 8-bit register from the LTC2990 using the standard repeated start format.
int8_t LTC2990_register_read(uint8_t i2c_address, uint8_t register_address, uint8_t *register_data)
{
  int8_t ack = 0;

  ack = i2c_read_byte_data(i2c_address, register_address, register_data);
  return(ack);
}

// Write one byte to an LTC2990 register.
// Writes to an 8-bit register inside the LTC2990 using the standard I2C repeated start format.
int8_t LTC2990_register_write(uint8_t i2c_address, uint8_t register_address, uint8_t register_data)
{
  int8_t ack = 0;

  ack = i2c_write_byte_data(i2c_address, register_address, register_data);
  return(ack);
}

// Used to set and clear bits in a control register.  bits_to_set will be bitwise OR'd with the register.
// bits_to_clear will be inverted and bitwise AND'd with the register so that every location with a 1 will result in a 0 in the register.
int8_t LTC2990_register_set_clear_bits(uint8_t i2c_address, uint8_t register_address, uint8_t bits_to_set, uint8_t bits_to_clear)
{
  uint8_t register_data;
  int8_t ack = 0;

  ack |= LTC2990_register_read(i2c_address, register_address, &register_data);  //! 1) Read register
  register_data = register_data & (~bits_to_clear); //! 2) Clear bits that were set to be cleared
  register_data = register_data | bits_to_set;
  ack |= LTC2990_register_write(i2c_address, register_address, register_data);  //! 3) Write to register with the cleared bits
  return(ack);
}

// Calculates the LTC2990 single-ended input voltages
float LTC2990_code_to_single_ended_voltage(int16_t adc_code, float LTC2990_single_ended_lsb)
{
  float voltage;
  int16_t sign = 1;
  if (adc_code >> 14)
  {
    adc_code = (adc_code ^ 0x7FFF) + 1;                 //! 1) Converts two's complement to binary
    sign = -1;
  }
  adc_code = (adc_code & 0x3FFF);
  voltage = ((float) adc_code) * LTC2990_single_ended_lsb * sign;   //! 2) Convert code to voltage from lsb
  return (voltage);
}

// Calculates the LTC2990 Vcc voltage
float LTC2990_code_to_vcc_voltage(int16_t adc_code, float LTC2990_single_ended_lsb)
{
  float voltage;
  int16_t sign = 1;
  if (adc_code >> 14)
  {
    adc_code = (adc_code ^ 0x7FFF) + 1;                 //! 1) Converts two's complement to binary
    sign = -1;
  }

  voltage = (((float) adc_code) * LTC2990_single_ended_lsb * sign) + 2.5; //! 2) Convert code to Vcc Voltage from single-ended lsb
  return (voltage);
}

// Calculates the LTC2990 differential input voltage.
float LTC2990_code_to_differential_voltage(int16_t adc_code, float LTC2990_differential_lsb)
{
  float voltage;
  int16_t sign = 1;
  if (adc_code >> 14)
  {
    adc_code = (adc_code ^ 0x7FFF) + 1;                 //! 1)Converts two's complement to binary
    sign = -1;
  }
  voltage = ((float) adc_code) * LTC2990_differential_lsb * sign;   //! 2) Convert code to voltage form differential lsb
  return (voltage);
}

// Calculates the LTC2990 temperature
float LTC2990_temperature(int16_t adc_code, float LTC2990_temperature_lsb, boolean unit)
{
  float temperature;
  adc_code = (adc_code & 0x1FFF);                               //! 1) Removes first 3 bits
  if (!unit)                                                     //! 2)Checks to see if it's Kelvin
  {
    if (adc_code >>12)
    {
      adc_code = (adc_code | 0xE000);                         //! Sign extend if it's not Kelvin (Celsius)
    }
  }
  temperature = ((float) adc_code) * LTC2990_temperature_lsb;   //! 3) Converts code to temperature from temperature lsb

  return (temperature);
}

//  Calculates the LTC2990 diode voltage
float LTC2990_code_to_diode_voltage(int16_t adc_code, float LTC2990_diode_voltage_lsb)
{
  float voltage;
  adc_code = (adc_code & 0x1FFF);                               //! 1) Removes first 3 bits
  voltage = ((float) adc_code) * LTC2990_diode_voltage_lsb;     //! 2) Convert code to voltage from diode voltage lsb
  return (voltage);
}