/*!
LTC6903: 1kHz to 68MHz Serial Port Programmable Oscillator

@verbatim

The LTC6903/LTC6904 are low power self contained digital
frequency sources providing a precision frequency from
1kHz to 68MHz, set through a serial port. The LTC6903/
LTC6904 require no external components other than a
power supply bypass capacitor, and they operate over a
single wide supply range of 2.7V to 5.5V.

@endverbatim

http://www.linear.com/product/LTC6903

http://www.linear.com/product/LTC6903#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
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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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*/

/*! @file
    @ingroup LTC6903
    Library Header File for LTC6903: 1kHz to 68MHz Serial Port Programmable Oscillator
*/

#ifndef LTC6903_H
#define LTC6903_H

#include <SPI.h>

//! Define the SPI CS pin
#ifndef LTC6903_CS
#define LTC6903_CS QUIKEVAL_CS
#endif

/*!
@{
|   OCT Options     |   f>=  (MHz)  |   f< (MHz)    |
|   :-----------    |   :--------:  |   :-------:   |
|   LTC6903_OCT_15  |   34.05       |   68.03       |
|   LTC6903_OCT_14  |   17.02       |   34.01       |
|   LTC6903_OCT_13  |   8.5111      |   17.01       |
|   LTC6903_OCT_12  |   4.256       |   8.503       |
|   LTC6903_OCT_11  |   2.128       |   4.252       |
|   LTC6903_OCT_10  |   1.064       |   2.126       |
|   LTC6903_OCT_9   |   0.532       |   1.063       |
|   LTC6903_OCT_8   |   0.266       |   0.5314      |
|   LTC6903_OCT_7   |   0.133       |   0.2657      |
|   LTC6903_OCT_6   |   0.0665      |   0.1329      |
|   LTC6903_OCT_5   |   0.03325     |   0.06643     |
|   LTC6903_OCT_4   |   0.01662     |   0.03322     |
|   LTC6903_OCT_3   |   0.008312    |   0.01661     |
|   LTC6903_OCT_2   |   0.004156    |   0.008304    |
|   LTC6903_OCT_1   |   0.002078    |   0.004152    |
|   LTC6903_OCT_0   |   0.001039    |   0.002076    |
*/
// OCT Options
// f>=  (MHz)       | f< (MHz)
#define LTC6903_OCT_15  0x0F    // 34.05            | 68.03
#define LTC6903_OCT_14  0x0E    // 17.02            | 34.01
#define LTC6903_OCT_13  0x0D    // 8.5111           | 17.01
#define LTC6903_OCT_12  0x0C    // 4.256            | 8.503
#define LTC6903_OCT_11  0x0B    // 2.128            | 4.252
#define LTC6903_OCT_10  0x0A    // 1.064            | 2.126
#define LTC6903_OCT_9   0x09    // 0.532            | 1.063
#define LTC6903_OCT_8   0x08    // 0.266            | 0.5314
#define LTC6903_OCT_7   0x07    // 0.133            | 0.2657
#define LTC6903_OCT_6   0x06    // 0.0665           | 0.1329
#define LTC6903_OCT_5   0x05    // 0.03325          | 0.06643
#define LTC6903_OCT_4   0x04    // 0.01662          | 0.03322
#define LTC6903_OCT_3   0x03    // 0.008312         | 0.01661
#define LTC6903_OCT_2   0x02    // 0.004156         | 0.008304
#define LTC6903_OCT_1   0x01    // 0.002078         | 0.004152
#define LTC6903_OCT_0   0x00    // 0.001039         | 0.002076
//! @}

// Output Configuration
#define LTC6903_CLK_ON_CLK_INV_ON   0x00    //!< Clock on, inverted clock on
#define LTC6903_CLK_OFF_CLK_INV_ON  0x01    //!< Clock off, inverted clock on
#define LTC6903_CLK_ON_CLK_INV_OFF  0x02    //!< Clock on, inverted clock off
#define LTC6903_POWER_DOWN          0x03    //!< Powers down clocks

//! Writes 2 bytes
//! @return 1 if successful, 0 if failure
void LTC6903_write(uint8_t cs,      //!< Chip Select Pin
                   uint16_t code    //!< Code to be written
                  );

//! Calculates the code necessary to create the clock frequency
//! @return the code for the LTC6903
uint16_t LTC6903_frequency_to_code(float frequency, //!< Clock frequency in MHz
                                   uint8_t clk       //!< Output configuration
                                  );

#endif