/*!
LTC2604: Quad 16-Bit Rail-to-Rail DACs in 16-Lead SSOP

@verbatim

The LTC2604/LTC2614/LTC2624 are quad 16-,14- and 12-bit 2.5V to 5.5V
rail-to-rail voltage output DACs in 16-lead narrow SSOP packages. These
parts have separate reference inputs for each DAC. They have built-in
high performance output buffers and are guaranteed monotonic.

These parts establish advanced performance standards for output drive,
crosstalk and load regulation in single-supply, voltage output multiples.

SPI DATA FORMAT (MSB First):

24-Bit Load Sequence:

             Byte #1                   Byte #2                         Byte #3
             Command                   MSB                             LSB
LTC2604-16 : C3 C2 C1 C0 A3 A2 A1 A0   D15 D14 D13 D12 D11 D10 D9 D8   D7 D6 D5 D4 D3 D2 D1 D0
LTC2604-14 : C3 C2 C1 C0 A3 A2 A1 A0   D13 D12 D11 D10 D9  D8  D7 D6   D5 D4 D3 D2 D1 D0 X  X
LTC2604-12 : C3 C2 C1 C0 A3 A2 A1 A0   D11 D10 D9  D8  D7  D6  D5 D4   D3 D2 D1 D0 X  X  X  X

32-Bit Load Sequence:

             Byte #1                   Byte #2                   Byte #3                         Byte #4
             Command                   MSB                                                       LSB
LTC2604-16 : X  X  X  X  X  X  X  X    C3 C2 C1 C0 A3 A2 A1 A0   D15 D14 D13 D12 D11 D10 D9 D8   D7 D6 D5 D4 D3 D2 D1 D0
LTC2604-14 : X  X  X  X  X  X  X  X    C3 C2 C1 C0 A3 A2 A1 A0   D13 D12 D11 D10 D9  D8  D7 D6   D5 D4 D3 D2 D1 D0 X  X
LTC2604-12 : X  X  X  X  X  X  X  X    C3 C2 C1 C0 A3 A2 A1 A0   D11 D10 D9  D8  D7  D6  D5 D4   D3 D2 D1 D0 X  X  X  X

Cx   : DAC Command Code
Ax   : DAC Address (0=DACA, 1=DACB, 2=DACC, 3=DACD, 0xFF=All DACs)
Dx   : DAC Data Bits
X    : Don't care


Example Code:

Set DAC A to to 2V for 16-bit DAC.

    shift_count = 0;    // 16-bit DAC does not have to be shifted
    dac_voltage = 2.0;  // Sets dac voltage variable to 2v

    dac_code = LTC2604_voltage_to_code(dac_voltage, LTC2604_lsb, LTC2604_offset);       // Calculate DAC code from voltage, lsb, and offset
    LTC2604_write(LTC2604_CS, LTC2604_CMD_WRITE_UPDATE, LTC2604_DAC_A, dac_code << shift_count);    // Set DAC A with DAC code

@endverbatim


http://www.linear.com/product/LTC2604

http://www.linear.com/product/LTC2604#demoboards



Copyright 2018(c) Analog Devices, Inc.

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

/*! @file
  @ingroup LTC2604
  Header for LTC2604: Quad 16-Bit Rail-to-Rail DACs in 16-Lead SSOP
*/


#ifndef LTC2604_H
#define LTC2604_H

#include <SPI.h>

//! Define the SPI CS pin
#ifndef LTC2604_CS
#define LTC2604_CS QUIKEVAL_CS
#endif


//! @name LTC2604 Command Codes
//!@{
//! OR'd together with the DAC address to form the command byte
#define  LTC2604_CMD_WRITE               0x00  //!< Write to input register n
#define  LTC2604_CMD_UPDATE              0x10  //!< Update (power up) DAC register n
#define  LTC2604_CMD_WRITE_UPDATE_ALL    0x20  //!< Write to input register n, update (power up) all
#define  LTC2604_CMD_WRITE_UPDATE        0x30  //!< Write to input register n, update (power up) all
#define  LTC2604_CMD_POWER_DOWN          0x40  //!< Power down n
#define  LTC2604_CMD_NO_OPERATION        0xF0  //!< No operation
//!@}

/*!
| DAC Addresses                | Value    |
| :--------------------------: | :------: |
|  LTC2605_DAC_A               |  0x00    |
|  LTC2605_DAC_B               |  0x01    |
|  LTC2605_DAC_C               |  0x02    |
|  LTC2605_DAC_D               |  0x03    |
|  LTC2605_DAC_ALL             |  0x0F    |
*/
/*! @name Dac Addresses
@{*/

// Which DAC to operate on
#define  LTC2604_DAC_A     0x00
#define  LTC2604_DAC_B     0x01
#define  LTC2604_DAC_C     0x02
#define  LTC2604_DAC_D     0x03
#define  LTC2604_DAC_ALL   0x0F
//

//! Write the 16-bit dac_code to the LTC2604
//! @return Void
void LTC2604_write(uint8_t cs,                            //!< Chip Select Pin
                   uint8_t dac_command,                   //!< Command Nibble, left-justified, lower nibble set to zero
                   uint8_t dac_address,                   //!< DAC Address Nibble, right justified, upper nibble set to zero
                   uint16_t dac_code                      //!< 16-bit DAC code
                  );

//! Calculate a LTC2604 DAC code given the desired output voltage and DAC address (0-3)
//! @return The 16-bit code to send to the DAC
uint16_t LTC2604_voltage_to_code(float dac_voltage,       //!< Voltage to send to DAC
                                 float LTC2604_lsb,       //!< LSB value (volts)
                                 int16_t LTC2604_offset   //!< Offset (volts)
                                );

//! Calculate the LTC2604 DAC output voltage given the DAC code, offset, and LSB value
//! @return Calculated voltage
float LTC2604_code_to_voltage(uint16_t dac_code,          //!< DAC code
                              float LTC2604_lsb,          //!< LSB value (volts)
                              int16_t LTC2604_offset      //!< Offset (volts)
                             );

#endif //LTC2604_H