LTC6947 - 超低ノイズ0.35GHz~6GHz分数分周方式シンセサイザ

特長

  • 低ノイズ分数分周方式PLL
  • ΔΣ変調器のスプリアスなし
  • 分数の分母:18ビット
  • VCO入力範囲:350MHz6GHz
  • 正規化された帯域内位相ノイズフロア:–226dBc/Hz
  • 正規化された帯域内1/fノイズ:–274dBc/Hz
  • 広帯域出力位相ノイズフロア:–157dBc/Hz
  • 優れた整数値境界スプリアス性能
  • 出力分周器(16分周、デューティ・サイクル50%
  • 出力バッファのミュート
  • チャージポンプ電源電圧:3.15V~5.25V
  • チャージポンプ電流:1mA~11.2mA
  • リファレンス入力周波数:最大425MHz
  • 周波数の素早い切り替え
  • FracNWizard™ソフトウェア設計ツールによるサポート

標準的応用例

LTC6947 Typical Application
LTC6947 Typical Application

概要

LTC®6947は、高性能、低ノイズの6GHz位相同期ループ(PLL)で、基準分周器、位相周波数検出器(PFD)、超低ノイズ・チャージポンプ、分数帰還分周器、およびVCO出力分周器を内蔵しています。

分数分周器は、スプリアス・レベルが極めて低い先進の4次ΔΣ変調器を採用しています。これにより、ループ帯域幅が広くなり、位相ノイズの積分値が極めて低くなります。

プログラム可能なVCO出力分周器は、分周範囲が1~6なので、出力の周波数範囲が広がります。差動、低ノイズの出力バッファでは、出力電力を–4.3dBm~+4.5dBmの範囲でユーザーがプログラム可能であり、デジタル入力ピンを介して、またはソフトウェアによってミュートすることができます。

超低ノイズのチャージポンプは、VCOのモニタに役立つ、高電圧と低電圧を選択可能なクランプ回路を内蔵しており、V+/2のバイアス電圧を供給するよう設定することもできます。

すべてのデバイス設定は、SPI互換のシリアル・ポートを介して制御します。

パッケージ

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprint compatible with Mentor Graphics PADS® v9.5 or later, and Cadence ORCAD® v16.5 or later.

パッケージの最新情報ならびに図面については、パッケージング情報を参照してください。

製品番号 パッケージ Code 温度 Package Drawing RoHSデータ
LTC6947IUFD#PBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LTC6947IUFD#TRPBF 4x5 QFN-28 UFD I 05-08-1712 Yes


LTC6947 Package Drawing

発注情報

各種パッケージと価格

製品番号 パッケージ 温度 価格(1~99個時) 価格(1000個時)* RoHSデータ
LTC6947IUFD#PBF 4x5 QFN-28 I $8.50 $5.95 Yes
LTC6947IUFD#TRPBF 4x5 QFN-28 I $8.56 $6.01 Yes
購入サンプルリクエスト
* 米ドル価格は、米国内における定められた数量に対する工場渡しでの単価です。変更される可能性がありますので、予算目的でのみご使用願います。米国以外の国における価格は、輸送費、税金、手数料、為替レートにより変動する場合があります。注文個数に応じた価格および納期については、リニアテクノロジー正規代理店までお問い合わせください。

評価キット

リニアテクノロジーのデモボードは、認定のお客様に無料で提供されます。デモボードをご希望の場合は、最寄りのセールスオフィスまたは代理店 にお問い合わせください。一部のデモボードは、このWebページ上でクレジットでもご購入いただけます。デモボードは評価目的でのみご使用ください。実際の最終アプリケーションにおける動作検証と信頼性の確認は、お客様の責任において行っていただきますようお願いいたし ます。

製品番号 概要 価格 Documentation
DC1846A-A LTC6947 Demo Board | Ultralow Noise and Spurious 350MHz to 6GHz Frac-N Synthesizer, VCO=2328-2536MHz , (Req DC590) $125.00
購入

Companion Boards

製品番号 概要 価格 Documentation
DC2026C Linduino One Isolated USB Demo Board: An Arduino- and QuikEval-Compatible Code Development Platform $75.00
DC2429A LT3042 Low Noise PLL/VCO Power Supply Board with Onboard 100MHz Reference Frequency $150.00
DC590B Isolated USB Serial Controller for Linear Technology QuikEval-Compatible Demo Boards $50.00
購入
ここをクリック 全デモボードリストがご覧いただけます。

アプリケーション

  • ワイヤレス基地局(LTE、WiMAX、W-CDMA、PCS)
  • 広帯域無線アクセス
  • マイクロ波によるデータ・リンク
  • 軍用無線およびセキュリティ保護された無線
  • テストおよび測定

Product Notifications

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ヘルプが必要ですか? 質問事項を英語で mylinear@linear.com

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Linduino

Linduino is an Arduino compatible platform for developing and distributing firmware libraries and code for SPI and I²C-compatible integrated circuits. The Linduino One board interfaces to more than 300 QuikEval demonstration cards, supporting a variety of product types including analog-to-digital converters (ADCs)digital-to-analog converters (DACs)power monitors, and more. Firmware libraries for individual devices are written in C and designed to be portable to a wide variety of processors and microcontrollers. Each library has a demonstration program that can be uploaded to the Linduino One platform to allow the circuit and software to be quickly and easily verified.

Click here for more information on Linduino

FracNWizard

Linear Technology FracNWizard is used to communicate with the LTC6947 and LTC6948 synthesizers. It uses the DC590 controller to translate between USB and SPI-compatible serial communications formats.

It also includes advanced PLL design and simulation capabilities. You may use it to:

  • Recommend part parameters based on your frequency plan
  • Design noise-optimized loop filters
  • Simulate loop frequency response and stability
  • Simulate VCO and Reference source noise
  • Simulate output noise characteristics and statistics
  • Import and export VCO, reference and output noise data

Click Here to Download FracNWizard

Code

Linduino is Linear Technology's Arduino compatible system for developing and distributing firmware libraries and example code for Linear Technology’s integrated circuits. The code below can be downloaded or copied and pasted into your project. Please visit the Linduino Home Page for demo board, manual and setup information.

This part is Code Supported: There is example code available for this part. The code below may rely on other drivers available in the full library.

Download LTC6947 - DC1846A Linduino .INO File

/*!
DC1846A
LTC6947: Ultralow Noise and Spurious 0.35GHz to 6GHz FracN Synthesizer 
    
@verbatim

  Setup:
    Set the terminal baud rate to 115200 and select the newline terminator.
    Refer to Demo Manual DC1846A.
    Ensure all jumpers are installed in the factory default positions.
    Two power supplies are needed for this demo board: a 5v and a 3.3v supply.
    The 5V powers the 5V supply and V+VCO turret.
    A reference frequency is also needed for this demo board, refer to the
    DC1846 Demo Manual for details.
    
    
Command Description:

                             *****Main Menu*****
    1-  Load Default Settings- Loads the SPI map that is identical to file 
        LTC6947_100MHz.fracnset that is supplied with the FracNWizard and mentioned
        in the DC1846A user's manual.  It assumes a 100MHz reference input and the
        default DC1846A BOM.  It should output a 2415MHz signal on RF+/-.
        
        ** If you want to use a different loop filter, reference frequency or different
        register settings.  Please use FracNWizard for the loop filter design and initial
        device setup.  The register settings from FracNWizard can be entered into menu option 2.
        
    2-  READ/WRITE to Registers Addresses- Selecting this option will cause all the registers to
        be read, stored to variables, and displayed.  The user will then have the option
        to write to one register address at a time.

    3-  READ/WRITE to Registers Fields- Selecting this option will allow the user
        to read or write to one register field name at a time. 
        
    4-  This function calculates and programs OD, ND, NUM based on the desired Frf,
        the reference frequency, and the current RD value.  Linduino One (Arduino Uno) are 
        limited to 32 bit floats, int and doubles.  Significant rounding errors are created 
        with this 32 bit limitation.  Therefore, this function uses 64bit math functions 
        specifically created to overcome this limitation.  After OD, ND, and NUM are programmed, 
        the program calibrates the LTC6947.  If other register need change see menu 2 or menu 3.
                 
    5-  This function stores the current SPI settings in the demo boards EEPROM
        
    6-  This function loads SPI settings from the demo boards EEPROM to the device   

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

@endverbatim

http://www.linear.com/product/LTC6947

http://www.linear.com/product/LTC6947#demoboards

REVISION HISTORY
$Revision: 3018 $
$Date: 2014-12-01 15:53:20 -0800 (Mon, 01 Dec 2014) $

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 LTC6947
*/

#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 "LTC6947.h"
#include <SPI.h>
#include <Wire.h>

// Function Declaration
void print_title();             // Print the title block
void print_prompt();            // Print the main menu
void menu_1_load_default_settings();  // Sub-menus
void menu_2_RW_to_reg_addresss();         
void menu_3_RW_to_reg_field();
void menu_4_set_frf();
void menu_5_store_settings();
void menu_6_restore_settings();

// Global Variables
static uint8_t ref_out = 0;            //!< Used to keep track of reference out status
static int8_t demo_board_connected;    //!< Demo Board Name stored in QuikEval EEPROM
uint8_t First_Run=0;                   //!< if first time through loop = 0, otherwise=1


/* ------------------------------------------------------------------------- */
//! Initialize Linduino
//! @return void
void setup() {
char demo_name[] = "DC1846";    // Demo Board Name stored in QuikEval EEPROM
uint8_t data;

quikeval_SPI_init();      //! Configure the spi port for 4MHz SCK
quikeval_SPI_connect();   //! Connect SPI to main data port
quikeval_I2C_init();      //! Configure the EEPROM I2C port for 100kHz
Serial.begin(115200);     //! Initialize the serial port to the PC
LTC6947_init();
print_title();

demo_board_connected = discover_demo_board(demo_name);  //! Checks if correct demo board is connected.

if (!demo_board_connected)
   while (1);                  //! Does nothing if the demo board is not connected

Serial.print(demo_board.name);
Serial.println(F(" was found"));

print_prompt();
} // end of setup()


/* ------------------------------------------------------------------------- */
//! Repeats Linduino loop
//! @return void
void loop(){
uint16_t user_command;          // User input command
  
if (Serial.available()) {        // Check for user input
   if(First_Run==0){
      First_Run=1;
      } 
 
    user_command = read_int();  //! Reads the user command
    if (user_command != 'm')
      Serial.println(user_command);
    
    switch (user_command) {     //! Prints the appropriate submenu
       case 1:
        menu_1_load_default_settings();
       break;
        
       case 2:
        menu_2_RW_to_reg_addresss(); 
       break;
        
       case 3:
        menu_3_RW_to_reg_field();
       break;
        
       case 4:
        menu_4_set_frf();
       break; 
  
       case 5:
        menu_5_store_settings(); 
       break; 
       
       case 6:
         menu_6_restore_settings(); 
       break;    
       
       default:
        Serial.println(F("Incorrect Option"));
       break;
    } // end of switch statement
  Serial.println(F("\n*****************************************************************"));
  print_prompt();
  } // end of if statement
} // end of loop()

// Function Definitions
/* ------------------------------------------------------------------------- */
//! Menu 1: Load Default SPI Register Settings
//!  This function loads the register settings referenced
//!  in the DC1846A demo manual's quick start section.
//!  The register settings loaded are the same as FRACN WIZARDS 
//!  fracnset files LTC6947_100MHz.fracnset 
//!  The setting loaded with this function assume the LTC6947's 
//!  reference is set to 100MHz and
//!  the DC1846A's BOM has not been modified.
//! @return void
void menu_1_load_default_settings(){

set_LTC6947_ALLREGS(LTC6947_CS, 0x04,0x00,0x06,0x9E,0x11,0x10,0x30,0x13,0x33,0x30,0x19,0x2D,0x00); 
Serial.println(F("Registers Have Been Written"));
} // end menu_1_load_default_settings function


/* ------------------------------------------------------------------------- */
//! Menu 2: Reads and/or Writes the SPI register address
//!  This function reads and displays all SPI register address settings in HEX format.
//!  It then provides an option to modify(write to) individual registers one at time
//! 
//!  EXAMPLE:
//!  - 0- ADDR00 = 0x04 (read only) 
//!  - 1- ADDR01 = 0x04
//!  - ....
//!  - 13- ADDR0D = 0x00
//!  - 14- ADDR0E = 0x10 (read only) 
//!  - 0 - Return to Main Menu
//!  - Enter a command (1-13 to modify register, or '0' to return to Main Menu): 
//! @return void
void menu_2_RW_to_reg_addresss(){
uint8_t i, regval, user_regval, num_reg;
uint16_t user_address;          // User input command

num_reg = get_LTC6947_REGSIZE();
user_address=1;
// Read/Write loop, can exit loop by choosing '0'
while  (user_address != 0) {
   Serial.println(F("\n*****************************************************************"));
   // Read All Registers and display results
   for(i=0; i<num_reg; i++) {
      regval = LTC6947_read(LTC6947_CS,i);
      Serial.print(i);
      if(i<16)
        Serial.print(F("- ADDR0"));
      else
        Serial.print(F("- ADDR"));
      Serial.print(i, HEX);
      Serial.print(F(" = 0x"));
      if(regval<16) Serial.print(F("0"));
      Serial.print(regval, HEX);
      if((i==0)||(i==(num_reg-1))) Serial.print(" (read only) ");
      if(i==2) Serial.print(" (warning: if D0=1 it resets all registers. Power On Reset Bit)");
      Serial.println("");
      }  // end for loop
   Serial.print("0 - Return to Main Menu\n\n");
   // User input: Select which register to modify, or return to main menu
   Serial.print("Enter a command (1-13 to modify register, or '0' to return to Main Menu): ");
   user_address = read_int();  //! Reads the user command
   Serial.println(user_address);

   // User input: enter new setting for selected register
   if (user_address >0 && user_address<(num_reg-1)) {
      Serial.print("What value should ADDR");
      Serial.print(user_address);
      Serial.print(" be set to (ex: HEX format 0xff): ");
      user_regval = read_int();  //! Reads the user command
      Serial.println(user_regval);

      // writes new setting to part
      LTC6947_write(LTC6947_CS, (uint8_t)user_address, user_regval);
      } // end if statement
   } // end while loop
}  // end menu_2_RW_to_reg_addresss


/* ------------------------------------------------------------------------- */
//! Support function for function menu_3_RW_to_reg_field  
//!  displays current state of select field 
//!  provides user the option to write to that field or return to menu
//!  @return field value (user input) that will be written to part
long field_menu_RW(long field_val,       //!< current state of the selected field
                   char field_name[],    //!< SPI Field name selected
                   uint8_t f             //!< SPI field identifier identifies selected fields information in SPI MAP arrays
                   ){
long usr_field_val;
uint8_t field_size, i;
long max_num=1, pow2=1;
  
Serial.print("CURRENT STATE (HEX): ");
Serial.print(field_name);
Serial.print("= 0x");
Serial.println(field_val, HEX);

if(get_LTC6947_SPI_FIELD_RW(f)==0){     
   field_size=get_LTC6947_SPI_FIELD_NUMBITS(f);
   for(i=1; i<field_size; i++) { 
      pow2=pow2*2; 
      max_num=max_num + pow2;}

   Serial.print("What value should ");
   Serial.print(field_name);
   Serial.print(" be set to or type '-1' to exit: (ex: HEX format 0x00 to 0x");
   Serial.print(max_num, HEX);
   Serial.print(")");
   usr_field_val = read_int();  //! Reads the user command

   if (usr_field_val>=0 && usr_field_val<=max_num){
      Serial.println(usr_field_val);
      return usr_field_val;
      }
   else {
      return field_val;
      } // end of if statement
   } // end of if statement
} // end of field_menu_RW


/* ------------------------------------------------------------------------- */
//! Menu 3: Reads and/or Writes individual SPI fields
//!  This function provides the user with a list of all SPI fields.
//!  The user can select a SPI field to read its current value.
//!  Then the user will be provided with an option to write to that field
//!  or return to the selection menu.
//!
//!  EXAMPLE:
//!  - 1-AUTORST      14-FILT         27-PDFN 
//!  - 2-BST          15-INTN         28-PDOUT
//!  - ....
//!  - 12-CPWIDE      25-PART *       38-UNLOK *
//!  - 13-DITHEN      26-PDALL        39-x 
//!  - 0 - Return to Main Menu
//!  - * = READ ONLY FIELD
//!  - Enter a command (1-39 to modify register, or '0' to return to Main Menu): 
//! @return void
void menu_3_RW_to_reg_field(){
uint8_t  field_num;
long field_val;

field_num=1;
// Read/Write loop, can exit loop by choosing 'm'
while  (field_num != 0) {
   Serial.println(F("\n*****************************************************************"));
   // Select Fields to read and write to
   Serial.print(F("1-AUTORST      14-FILT         27-PDFN\n"));
   Serial.print(F("2-BST          15-INTN         28-PDOUT\n"));
   Serial.print(F("3-CP           16-LDOEN        29-PDPLL\n"));
   Serial.print(F("4-CPCHI        17-LDOV         30-POR\n"));
   Serial.print(F("5-CPCLO        18-LKCT         31-RD\n"));
   Serial.print(F("6-CPDN         19-LKWIN        32-REV *\n"));
   Serial.print(F("7-CPINV        20-LOCK *       33-RFO\n"));
   Serial.print(F("8-CPLE         21-ND           34-RSTFN\n"));
   Serial.print(F("9-CPMID        22-NUM          35-SEED\n"));
   Serial.print(F("10-CPRST       23-OD           36-THI *\n"));
   Serial.print(F("11-CPUP        24-OMUTE        37-TLO *\n"));
   Serial.print(F("12-CPWIDE      25-PART *       38-UNLOK *\n"));
   Serial.print(F("13-DITHEN      26-PDALL        39-x\n"));
   Serial.print("0 - Return to Main Menu\n");
   Serial.print("* = READ ONLY FIELD\n\n");

   Serial.print("Enter a command (1-39 to modify register, or '0' to return to Main Menu): ");
   field_num = read_int();  //! Reads the user command
   Serial.println(field_num);
  
   // User input: enter new setting for selected register
   if (field_num != 0) {
      switch (field_num) {      //! Prints the appropriate submenu
         case LTC6947_AUTORST:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_AUTORST);    // reads selected field   
           field_val=field_menu_RW(field_val,"AUTORST",LTC6947_AUTORST);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_AUTORST, field_val);}   // updates selected field
         break;

         case LTC6947_BST:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_BST);    // reads selected field   
           field_val=field_menu_RW(field_val,"BST",LTC6947_BST);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_BST, field_val);}   // updates selected field
         break;

         case LTC6947_CP:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CP);    // reads selected field   
           field_val=field_menu_RW(field_val,"CP",LTC6947_CP);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CP, field_val);}   // updates selected field
         break;

         case LTC6947_CPCHI:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPCHI);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPCHI",LTC6947_CPCHI);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPCHI, field_val);}   // updates selected field
         break;

         case LTC6947_CPCLO:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPCLO);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPCLO",LTC6947_CPCLO);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPCLO, field_val);}   // updates selected field
         break;

         case LTC6947_CPDN:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPDN);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPDN",LTC6947_CPDN);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPDN, field_val);}   // updates selected field
         break;

         case LTC6947_CPINV:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPINV);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPINV",LTC6947_CPINV);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPINV, field_val);}   // updates selected field
         break;

         case LTC6947_CPLE:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPLE);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPLE",LTC6947_CPLE);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPLE, field_val);}   // updates selected field
         break;

         case LTC6947_CPMID:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPMID);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPMID",LTC6947_CPMID);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPMID, field_val);}   // updates selected field
         break;

         case LTC6947_CPRST:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPRST);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPRST",LTC6947_CPRST);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPRST, field_val);}   // updates selected field
         break;

         case LTC6947_CPUP:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPUP);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPUP",LTC6947_CPUP);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPUP, field_val);}   // updates selected field
         break;

         case LTC6947_CPWIDE:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_CPWIDE);    // reads selected field   
           field_val=field_menu_RW(field_val,"CPWIDE",LTC6947_CPWIDE);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_CPWIDE, field_val);}   // updates selected field
         break;

         case LTC6947_DITHEN:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_DITHEN);    // reads selected field   
           field_val=field_menu_RW(field_val,"DITHEN",LTC6947_DITHEN);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_DITHEN, field_val);}   // updates selected field
         break;

         case LTC6947_FILT:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_FILT);    // reads selected field   
           field_val=field_menu_RW(field_val,"FILT",LTC6947_FILT);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_FILT, field_val);}   // updates selected field
         break;

         case LTC6947_INTN:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_INTN);    // reads selected field   
           field_val=field_menu_RW(field_val,"INTN",LTC6947_INTN);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_INTN, field_val);}   // updates selected field
         break;

         case LTC6947_LDOEN:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_LDOEN);    // reads selected field   
           field_val=field_menu_RW(field_val,"LDOEN",LTC6947_LDOEN);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_LDOEN, field_val);}   // updates selected field
         break;

         case LTC6947_LDOV:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_LDOV);    // reads selected field   
           field_val=field_menu_RW(field_val,"LDOV",LTC6947_LDOV);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_LDOV, field_val);}   // updates selected field
         break;

         case LTC6947_LKCT:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_LKCT);    // reads selected field   
           field_val=field_menu_RW(field_val,"LKCT",LTC6947_LKCT);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_LKCT, field_val);}   // updates selected field
         break;

         case LTC6947_LKWIN:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_LKWIN);    // reads selected field   
           field_val=field_menu_RW(field_val,"LKWIN",LTC6947_LKWIN);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_LKWIN, field_val);}   // updates selected field
         break;

         case LTC6947_LOCK:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_LOCK);    // reads selected field   
           field_val=field_menu_RW(field_val,"LOCK",LTC6947_LOCK);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_LOCK, field_val);}   // updates selected field
         break;

         case LTC6947_ND:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_ND);    // reads selected field   
           field_val=field_menu_RW(field_val,"ND",LTC6947_ND);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_ND, field_val);}   // updates selected field
         break;

         case LTC6947_NUM:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_NUM);    // reads selected field   
           field_val=field_menu_RW(field_val,"NUM",LTC6947_NUM);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_NUM, field_val);}   // updates selected field
         break;

         case LTC6947_OD:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_OD);    // reads selected field   
           field_val=field_menu_RW(field_val,"OD",LTC6947_OD);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_OD, field_val);}   // updates selected field
         break;

         case LTC6947_OMUTE:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_OMUTE);    // reads selected field   
           field_val=field_menu_RW(field_val,"OMUTE",LTC6947_OMUTE);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_OMUTE, field_val);}   // updates selected field
         break;

         case LTC6947_PART:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_PART);    // reads selected field   
           field_val=field_menu_RW(field_val,"PART",LTC6947_PART);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_PART, field_val);}   // updates selected field
         break;

         case LTC6947_PDALL:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_PDALL);    // reads selected field   
           field_val=field_menu_RW(field_val,"PDALL",LTC6947_PDALL);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_PDALL, field_val);}   // updates selected field
         break;

         case LTC6947_PDFN:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_PDFN);    // reads selected field   
           field_val=field_menu_RW(field_val,"PDFN",LTC6947_PDFN);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_PDFN, field_val);}   // updates selected field
         break;

         case LTC6947_PDOUT:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_PDOUT);    // reads selected field   
           field_val=field_menu_RW(field_val,"PDOUT",LTC6947_PDOUT);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_PDOUT, field_val);}   // updates selected field
         break;

         case LTC6947_PDPLL:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_PDPLL);    // reads selected field   
           field_val=field_menu_RW(field_val,"PDPLL",LTC6947_PDPLL);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_PDPLL, field_val);}   // updates selected field
         break;

         case LTC6947_POR:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_POR);    // reads selected field   
           field_val=field_menu_RW(field_val,"POR",LTC6947_POR);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_POR, field_val);}   // updates selected field
         break;

         case LTC6947_RD:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_RD);    // reads selected field   
           field_val=field_menu_RW(field_val,"RD",LTC6947_RD);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_RD, field_val);}   // updates selected field
         break;

         case LTC6947_REV:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_REV);    // reads selected field   
           field_val=field_menu_RW(field_val,"REV",LTC6947_REV);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_REV, field_val);}   // updates selected field
         break;

         case LTC6947_RFO:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_RFO);    // reads selected field   
           field_val=field_menu_RW(field_val,"RFO",LTC6947_RFO);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_RFO, field_val);}   // updates selected field
         break;

         case LTC6947_RSTFN:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_RSTFN);    // reads selected field   
           field_val=field_menu_RW(field_val,"RSTFN",LTC6947_RSTFN);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_RSTFN, field_val);}   // updates selected field
         break;

         case LTC6947_SEED:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_SEED);    // reads selected field   
           field_val=field_menu_RW(field_val,"SEED",LTC6947_SEED);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_SEED, field_val);}   // updates selected field
         break;

         case LTC6947_THI:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_THI);    // reads selected field   
           field_val=field_menu_RW(field_val,"THI",LTC6947_THI);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_THI, field_val);}   // updates selected field
         break;

         case LTC6947_TLO:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_TLO);    // reads selected field   
           field_val=field_menu_RW(field_val,"TLO",LTC6947_TLO);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_TLO, field_val);}   // updates selected field
         break;

         case LTC6947_UNLOK:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_UNLOK);    // reads selected field   
           field_val=field_menu_RW(field_val,"UNLOK",LTC6947_UNLOK);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_UNLOK, field_val);}   // updates selected field
         break;

         case LTC6947_x:
           field_val=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_x);    // reads selected field   
           field_val=field_menu_RW(field_val,"x",LTC6947_x);      // user interface control and printout
           if(field_val>-1)  {set_LTC6947_SPI_FIELD(LTC6947_CS, LTC6947_x, field_val);}   // updates selected field
         break;
         }  // end of switch statement
      } // end if user_command != 0 statement
   } // end while loop
}  // end menu_3_RW_to_reg_field function


/* ------------------------------------------------------------------------- */
//! verifies VCO frequency is within datasheet specifications
void LTC6947_VCO_Freq_Verification(){
unsigned long temp_val, temp_max_VCO_MHz, temp_min_VCO_MHz, temp_max_VCO_Hz, temp_min_VCO_Hz;
unsigned long fvco_max[2], fvco_min[2], fvco_max_lim[2], fvco_min_lim[2];
boolean valid_input=false;

// USER INPUT
valid_input=false;


while (valid_input==false) {
   temp_max_VCO_MHz=get_LTC6947_global_VCO_MAX_MHz();
   temp_min_VCO_MHz=get_LTC6947_global_VCO_MIN_MHz();
   temp_max_VCO_Hz=get_LTC6947_global_VCO_MAX_Hz();
   temp_min_VCO_Hz=get_LTC6947_global_VCO_MIN_Hz();

   Serial.print(F("What is the upper frequency limit of the VCO (MHZ portion)? ["));
   Serial.print(temp_max_VCO_MHz);
   Serial.print(F("]: "));
   temp_val = read_float();  //! Reads the user command
   // if user selects enter, keep same Fref.  Otherwise set Fref and verify
   if(temp_val!=0) temp_max_VCO_MHz = abs(temp_val);
   Serial.println(temp_max_VCO_MHz);

   Serial.print(F("What is the upper VCO frequency limit (HZ portion)? "));
   temp_max_VCO_Hz = read_float();  //! Reads the user command
   // if user selects enter, keep same Fref.  Otherwise set Fref and verify
   Serial.println(temp_max_VCO_Hz);

   Serial.print(F("\nWhat is the lower frequency limit of the VCO (MHZ portion)? ["));
   Serial.print(temp_min_VCO_MHz);
   Serial.print(F("]: "));
   temp_val = read_float();  //! Reads the user command
   // if user selects enter, keep same Fref.  Otherwise set Fref and verify
   if(temp_val!=0) temp_min_VCO_MHz = abs(temp_val);
   Serial.println(temp_min_VCO_MHz);

   Serial.print(F("What is the lower frequency limit of the VCO (HZ portion)? "));
   temp_min_VCO_Hz = read_float();  //! Reads the user command
   Serial.println(temp_min_VCO_Hz);
   
   HZto64(fvco_max,temp_max_VCO_MHz,temp_max_VCO_Hz);  // convert to 64 bit integer
   HZto64(fvco_min,temp_min_VCO_MHz,temp_min_VCO_Hz);  // convert to 64 bit integer
   HZto64(fvco_max_lim,LTC6947_MAXFREQ,0);  // convert to 64 bit integer
   HZto64(fvco_min_lim,LTC6947_MINFREQ,0);  // convert to 64 bit integer


   // if valid input print the following to the screen
if (lt64(fvco_min_lim,fvco_min) && lt64(fvco_max,fvco_max_lim) &&
    lt64(fvco_min_lim,fvco_max) && lt64(fvco_min,fvco_max_lim) &&
    (eq64(fvco_min, fvco_max) || lt64(fvco_min, fvco_max)) ) {   
      set_LTC6947_global_vcolim(temp_max_VCO_MHz, temp_max_VCO_Hz, temp_min_VCO_MHz, temp_min_VCO_Hz);
      Serial.print(F("VCO Frequencies entered are valid\n"));
      valid_input=true;
      }
    else {
      Serial.print(F("VCO Frequencies must be between 350MHz and 6000MHz\n"));
      }  // end of if-else
   } // end of while
}  // end of LTC6947_VCO_Freq_Verification


/* ------------------------------------------------------------------------- */
//! verifies reference frequency is within datasheet specifications

void LTC6947_Ref_Freq_Verification(){
unsigned long temp_val, temp_fref_MHz, temp_fref_Hz;
boolean valid_input=false;

// USER INPUT
valid_input=false;


while (valid_input==false) {
   temp_fref_MHz=get_LTC6947_global_fref_MHz();
   temp_fref_Hz=get_LTC6947_global_fref_Hz();
   Serial.print(F("\nWhat is the MHz portion of the Reference Input Frequency(MHZ)? ["));
   Serial.print(temp_fref_MHz);
   Serial.print(F("]: "));
   temp_val = read_float();  //! Reads the user command
   // if user selects enter, keep same Fref.  Otherwise set Fref and verify
   if(temp_val!=0) temp_fref_MHz = abs(temp_val);
   Serial.println(temp_fref_MHz);

   Serial.print(F("What is the sub-MHz portion of the Reference Input Frequency(HZ)? "));
   temp_val = read_float();  //! Reads the user command
   temp_fref_Hz = abs(temp_val);   
   Serial.println(temp_fref_Hz);

   // if valid input print the following to the screen
   if(temp_fref_MHz >=LTC6947_MIN_REF_FREQ & temp_fref_MHz <= LTC6947_MAX_REF_FREQ) {
      set_LTC6947_global_fref(temp_fref_MHz,temp_fref_Hz);
      temp_val= temp_fref_MHz*OneMHz + temp_fref_Hz;
      Serial.print(F("Reference Frequency set to ")); 
      Serial.print(temp_val);
      Serial.println(F("Hz"));
      valid_input=true;
      }
    else {
      Serial.print(F("Reference Frequency must be between 10MHz and 425MHz\n"));
      }  // end of if-else
   } // end of while
}  // end of LTC6947_Ref_Freq_Verification


/* ------------------------------------------------------------------------- */
//! verifies frf frequency is within datasheet specifications
void LTC6947_Fout_Freq_Verification(){
unsigned long odiv, temp_fout_MHz, temp_fout_Hz, temp_val;
unsigned long frf[2];
boolean valid_input=false;

// USER INPUT
temp_fout_MHz=get_LTC6947_global_frf_MHz();
temp_fout_Hz=get_LTC6947_global_frf_Hz();

while(valid_input==false){
   Serial.print(F("\nWhat is the MHz portion of the Output Frequency(MHZ)? ["));
   Serial.print(temp_fout_MHz);
   Serial.print(F("]: "));
   temp_val = read_int();  //! Reads the user command
   // if user selects enter, keep same Fout.  Otherwise set Fout and verify
   if(temp_val!=0) temp_fout_MHz = abs(temp_val);
   Serial.println(temp_fout_MHz);

   Serial.print(F("What is the Hz portion of the Output Frequency(HZ)? "));
   temp_val = read_int();  //! Reads the user command
   temp_fout_Hz = abs(temp_val);
   Serial.println(temp_fout_Hz);
   
   HZto64(frf,temp_fout_MHz,temp_fout_Hz);  // convert to 64 bit integer

   // verify desired frequency falls within a divider range (1-6)  
   odiv = LTC6947_calc_odiv(frf);
   valid_input=false;
   if((odiv>=1) && (odiv<=6)) valid_input=true;
 
   // if valid input print the following to the screen
   if(valid_input==true) {
      set_LTC6947_global_frf(temp_fout_MHz,temp_fout_Hz);
      if(temp_fout_MHz < 4294) {
         temp_val= temp_fout_MHz*OneMHz + temp_fout_Hz;
         Serial.print(F("Desired Output Frequency is ")); 
         Serial.print(temp_val);
         Serial.println(F("Hz"));
         }
      else {  // over flow condition
         Serial.print(F("Desired Output Frequency is ")); 
         Serial.print(temp_fout_MHz);
         Serial.print(F("MHz + "));
         Serial.print(temp_fout_Hz);
         Serial.println(F("Hz"));
         }
       }
    // if invalid input print the following to the screen
   else {
      Serial.println(F("Invalid Fout frequency chosen"));
      } // end of if/else (valid_input==true)
   } // end of while(valid_input=false)
} // end of Fout_Freq_Verification


/* ------------------------------------------------------------------------- */
//! Menu 4: Calculates and programs OD, ND, NUM based on desired Frf
//!  This function calculates and programs OD, ND, NUM based on desired Frf,
//!  the reference frequency, and current RD value.  
//!  Linduino One (Arduino Uno) are limited to 32 bit floats, int and doubles.
//!  Significant rounding errors are created with this 32 bit limitation.  Therefore,
//!  This function uses 64bit math functions specifically created to overcome this limitation.
//!  If RD needs to change see menu 2 or menu 3
//! @return void
void menu_4_set_frf(){
Serial.print(F("\nThis function calculates and programs OD, ND, NUM\n"));
Serial.print(F("based on the value input for Fvco, Frf and Fref.\n"));
Serial.print(F("It assumes all other register settings are correct\n"));
Serial.print(F("The FracNWizard tool can verify the correctness of the other register settings.\n"));


Serial.print(F("\nThe following frequencies will be entered with 2 integers\n"));
Serial.print(F("1st number is the MHZ portion, the 2nd number is Hz portion\n"));
Serial.print(F(" - Example: A. 100\n"));
Serial.print(F("            B. 25\n"));
Serial.print(F("   equates to 100.000025MHZ\n\n"));
LTC6947_VCO_Freq_Verification();
LTC6947_Ref_Freq_Verification();
LTC6947_Fout_Freq_Verification();
LTC6947_set_frf();
}

/* ------------------------------------------------------------------------- */
//! Store PLL settings to nonvolatile EEPROM on demo board
//! @return void
void menu_5_store_settings() {
// Store the PLL Settings to the EEPROM
uint8_t regval;

uint8_t addr_offset;
uint8_t num_reg;

addr_offset=2;
num_reg = get_LTC6947_REGSIZE();
 
eeprom_write_int16(EEPROM_I2C_ADDRESS, EEPROM_CAL_KEY, EEPROM_CAL_STATUS_ADDRESS);         // Cal key
  
for (uint8_t i = 0; i <= num_reg ; i++){
   regval = LTC6947_read(LTC6947_CS,i);
   eeprom_write_byte(EEPROM_I2C_ADDRESS,(char) regval, EEPROM_CAL_STATUS_ADDRESS+ i+addr_offset);
   }
Serial.println(F("PLL Settings Stored to EEPROM"));

}


/* ------------------------------------------------------------------------- */
//! Read stored PLL settings from nonvolatile EEPROM on demo board
//! @return void
void menu_6_restore_settings() {
// Read the PLL settings from EEPROM
int16_t cal_key;
uint8_t regval;
uint8_t user_address;

uint8_t addr_offset;
uint8_t num_reg;

addr_offset=2;
num_reg = get_LTC6947_REGSIZE();

// read the cal key from the EEPROM
eeprom_read_int16(EEPROM_I2C_ADDRESS, &cal_key, EEPROM_CAL_STATUS_ADDRESS);
if (cal_key == EEPROM_CAL_KEY) {
   // PLL Settings has been stored, read PLL Settings
   user_address=2;
   for (uint8_t i = 0; i <= num_reg ; i++) {
      eeprom_read_byte(EEPROM_I2C_ADDRESS,(char *) &regval, EEPROM_CAL_STATUS_ADDRESS + i+addr_offset);
      LTC6947_write(LTC6947_CS, (uint8_t)i, regval);
      user_address++;
      }
   Serial.println(F("PLL Settings Restored"));
   }
else {
   Serial.println(F("PLL Settings not found"));
   }

}

/* ------------------------------------------------------------------------- */
//!    Prints the title block when program first starts.
void print_title() {
  
Serial.println(F("*****************************************************************"));
Serial.println(F("* DC1846 Demonstration Program                                  *"));
Serial.println(F("*                                                               *"));
Serial.println(F("* This program demonstrates how to send data to the LTC6947     *"));
Serial.println(F("* Ultra Low Noise & Spurious FracN Synthesizer.                 *"));
Serial.println(F("*                                                               *"));
Serial.println(F("* Set the baud rate to 115200 and select the newline terminator.*"));
Serial.println(F("*                                                               *"));
Serial.println(F("* For loop filter design please use the FracN Wizard software.  *"));
Serial.println(F("* - It is recommended to use FracNWizard to determine the       *"));
Serial.println(F("* correct SPI register values for the initial setup.  These     *"));
Serial.println(F("* values can be entered into this program via menu option 2     *"));
Serial.println(F("* below.  These values can then be stored and recalled from the *"));
Serial.println(F("* DC1846 EEPROM using options 5 and 6 below.                    *"));
Serial.println(F("*****************************************************************"));
Serial.println();
} // end of print_title


/* ------------------------------------------------------------------------- */
//!    Prints main menu.
void print_prompt() {
  
Serial.println(F("\nCommand Summary:"));
Serial.println(F("  1-Load Default Settings (same as the FracN Wizard's LTC6947_100MHz.fracnset settings)"));
Serial.println(F("  2-READ/WRITE to Registers Addresses"));
Serial.println(F("  3-READ/WRITE to Registers Fields"));
Serial.println(F("  4-Set Output Frequency (Frf)"));
Serial.println(F("  5-Store LTC6947 SPI settings to the DC1846's EEPROM"));
Serial.println(F("  6-Restore LTC6947 SPI settings from the DC1846's EEPROM"));
Serial.println("");
Serial.print(F("Enter a command: "));
} // end of print_prompt


Download LTC6947 - Linduino Header File

/*!
 LTC6947: Ultralow Noise and Spurious 0.35GHz to 6GHz FracN Synthesizer 

@verbatim
 SPI DATA FORMAT (MSB First):

 Write Sequence:
       Byte #1                    Byte #2
 MOSI: A6 A5 A4 A3 A2 A1 A0 W   D7 D6 D5 D4 D3 D2 D1 D0
 MISO: X  X  X  X  X  X  X  X   X  X  X  X  X  X  X  X

 Read Sequence:
       Byte #1                    Byte #2
 MOSI: A6 A5 A4 A3 A2 A1 A0 R   X  X  X  X  X  X  X  X
 MISO: X  X  X  X  X  X  X  X   D7 D6 D5 D4 D3 D2 D1 D0

 W    : SPI Write (0)
 R    : SPI Read  (1)
 Ax   : Address
 Dx   : Data Bits
 X    : Don't care

@endverbatim

http://www.linear.com/product/LTC6947

http://www.linear.com/product/LTC6947#demoboards

REVISION HISTORY
$Revision: 3018 $
$Date: 2014-12-01 15:53:20 -0800 (Mon, 01 Dec 2014) $

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 LTC6947
    Header for LTC6947: Ultralow Noise and Spurious 0.35GHz to 6.39GHz FracN Synthesizer
*/

#ifndef LTC6947_H

#define LTC6947_H


//! Define the SPI CS pin
#ifndef LTC6947_CS
#define LTC6947_CS QUIKEVAL_CS  //! SPI Chip Select Pin
#endif


/*! @name LTC6947 Registers Fields in Alphabetical Order */
#define LTC6947_AUTORST 1   //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_BST 2       //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CP 3        //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPCHI 4     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPCLO 5     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPDN 6      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPINV 7     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPLE 8      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPMID 9     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPRST 10    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPUP 11     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_CPWIDE 12   //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_DITHEN 13   //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_FILT 14     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_INTN 15     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_LDOEN 16    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_LDOV 17     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_LKCT 18     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_LKWIN 19    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_LOCK 20     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_ND 21       //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_NUM 22      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_OD 23       //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_OMUTE 24    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_PART 25     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_PDALL 26    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_PDFN 27     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_PDOUT 28    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_PDPLL 29    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_POR 30      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_RD 31       //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_REV 32      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_RFO 33      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_RSTFN 34    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_SEED 35     //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_THI 36      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_TLO 37      //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_UNLOK 38    //!<  for spi_map array, defines location for field specific information used to create the spi map
#define LTC6947_x 39        //!<  for spi_map array, defines location for field specific information used to create the spi map


#define LTC6947_NUM_REGADDR 15  //!< Defines number of LTC6947 SPI registers, used in spi_map array
#define LTC6947_NUM_REGFIELD 39 //!< Defines number of LTC6947 SPI fields, used in spi_map array

#define ADDRx 0                 //!< used for 2nd dim of 2d spi_map array
#define DxMSB 1                 //!< used for 2nd dim of 2d spi_map array
#define NUMBITS 2               //!< used for 2nd dim of 2d spi_map array
#define R_ONLY 3                //!< used for 2nd dim of 2d spi_map array

#define OneMHz 1000000L         //!< 1MHz in long format, used in 64 bit math

#define LTC6947_MINFREQ 350   //!< LTC6947 lower freq limit
#define LTC6947_MAXFREQ 6000  //!< LTC6947 upper freq limit

#define LTC6947_MIN_REF_FREQ 10  //!< LTC6947 lower reference frequency limit
#define LTC6947_MAX_REF_FREQ 425 //!< LTC6947 upper reference frequency limit

//! @} */

/* ------------------------------------------------------------------------- */
//! LTC6947 Read Single Address
//!  reads 8 bit Data field to LTC6947.
//!  has to shift data by one bit to account for RW bit
//! @return data that was read from address
uint8_t LTC6947_read(uint8_t cs,    //!< Chip Select Pin
                     int8_t address //!< Register address for the LTC6947.
                    );

                    
/* ------------------------------------------------------------------------- */
//! LTC6947 Read Single Field
//! For SPI FIELDS located in 1 or multiple address location
//!  reads specific address locations
//!  identifies and returns specific field in question
//!  can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
//! @return data that was read from field
 long LTC6947_read_field(uint8_t cs,       //!< Chip Select Pin
                         uint8_t address,  //!< Register address for the LTC6947.
                         uint8_t MSB_loc,  //!< MSB bit location of field
                         uint8_t numbits   //!< length of field (i.e. number of bits in field)                    
                        );
 
 
/* ------------------------------------------------------------------------- */
//! Gets the LTC6947 SPI field value
//! calls function LTC6947_read_field, which
//!  reads specific address locations
//!  identifies and returns specific field in question
//!  can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
//! @return data that was read from field
long get_LTC6947_SPI_FIELD(uint8_t cs,          //!< Chip Select Pin
                           uint8_t f            //!< SPI field number
                          );
        
        
/* ------------------------------------------------------------------------- */
//! LTC6947 Write Single Address
//!  writes 8 bit Data field to LTC6947.
//!  has to shift data by one bit to account for RW bit
//! @return void
void LTC6947_write(uint8_t cs,                  //!< Chip Select Pin
                   uint8_t address,             //!< Register address for the LTC6947.
                   uint8_t Data                 //!< 8-bit data to be written to register
                  );

                  
/* ------------------------------------------------------------------------- */
//! LTC6947 Write Single Field
//!  For SPI FIELDS in 1 or multiple address locations
//!  reads specific address/field location then writes to specific field
//!  can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
//! @return void
 uint8_t LTC6947_write_field(uint8_t cs,        //!< Chip Select Pin
                             long field_data,   //!< Value field value to be set to
                             uint8_t address,   //!< Register address for the LTC6947.
                             uint8_t MSB_loc,   //!< MSB bit location of field
                             uint8_t numbits   //!< length of field (i.e. number of bits in field)
                            );
 
 
/* ------------------------------------------------------------------------- */
//! Sets the LTC6947 SPI field value
//! calls function LTC6947_read_field, which
//!  reads specific address/field location then writes to specific field
//!  can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
//! @return void
void set_LTC6947_SPI_FIELD(uint8_t cs,          //!< Chip Select Pin
                           uint8_t f,           //!< SPI field number
                           long field_data      //!< Value field value to be set to
                          );

                          
/* ------------------------------------------------------------------------- */
//! Writes values to ALL LTC6947 RW addresses
//! @return void
void set_LTC6947_ALLREGS(uint8_t cs,            //!< Chip Select Pin
                         uint8_t reg01,         //!< LTC6947 register 1
                         uint8_t reg02,         //!< LTC6947 register 2   
                         uint8_t reg03,         //!< LTC6947 register 3 
                         uint8_t reg04,         //!< LTC6947 register 4 
                         uint8_t reg05,         //!< LTC6947 register 5 
                         uint8_t reg06,         //!< LTC6947 register 6
                         uint8_t reg07,         //!< LTC6947 register 7
                         uint8_t reg08,         //!< LTC6947 register 8
                         uint8_t reg09,         //!< LTC6947 register 9
                         uint8_t reg0A,         //!< LTC6947 register 10
                         uint8_t reg0B,         //!< LTC6947 register 11
                         uint8_t reg0C,         //!< LTC6947 register 12
                         uint8_t reg0D          //!< LTC6947 register 13
                        );

/* ------------------------------------------------------------------------- */
//! Initializes the SPI MAP arrays
//! The values set in initialization are used for all the LTC6947 SPI/WRITE and 
//! read functions (set_LTC6947_SPI_FIELD, get_LTC6947_SPI_FIELD,
//! LTC6947_read, LTC6947_write, etc, etc)
//! @return void
void LTC6947_init();


/* ------------------------------------------------------------------------- */
//! returns # of addresses in parts register map (array size)
//! @return # of addresses in parts register map
uint8_t get_LTC6947_REGSIZE();


/* ------------------------------------------------------------------------- */
//! returns the number of bits for a given field name in the SPI map
//! @return the number of bits for a given field name in the SPI map
uint8_t get_LTC6947_SPI_FIELD_NUMBITS(uint8_t f //!< SPI field number 
                                      );

                                      
/* ------------------------------------------------------------------------- */
//! returns if the given field name is (0)read/write or (1)read_only field
//! @return if the given field is a (0)read/write or (1)read_only field
uint8_t get_LTC6947_SPI_FIELD_RW(uint8_t f   //!< SPI field number 
                                ) ; 

                                
/* ------------------------------------------------------------------------- */ 
//! calculates the output divider setting based on the frf and on board
//! VCO frequencies of LTC6947
//! @return odiv = 1-6 divider setting for valid frequency, or 999 for invalid frequency
unsigned long LTC6947_calc_odiv(unsigned long frf[2]    //!< output frequency
                                );  

/* ------------------------------------------------------------------------- */ 
//! FUNCTION: LTC6947_set_frf
//!  Calculates the integer (N), fractional (NUM) and output divider (OD) SPI values
//!  using self created 64bit math functions.
//!   
//! Datasheet equations:
//! - fvco = fpfd*(N + F)
//! - frf  = fvco/O
//! - fpfd = fref/R
//!    - F=NUM/2^18 = NUM/262144
//!    
//!    can be modified to the following equations:
//!    - N   = (int) (fvco/fpfd)  = (int) frf*O*R/fref
//!    - NUM = (int) [262144 * (frf*O*R/fref -N)]
//!    
//!    where:
//!    - N = ndiv, O= odiv, NUM=fracN_num  in the code below
//!    
//!    Linduino One (Arduino Uno) is limited to 32 bit floats/double/long.
//!    32 bit math functions will create rounding errors with the above equations, 
//!    that can result in frequency errors.
//!    Therefore, the following code uses self created 64bit functions for 64bit integer math.
//!    
//!    - frf (33 bits) LTC6947 max frf/fvco = 6GHZ, which is 33 bit number (2^33 = 8.59G)
//!    - fref (23 bits) LTC6947 min fref = 10MHz, which is a 23 bit number (2^23 = 8.3M)
//!    - O   (3 bits)
//!    - R   (5 bits)
//!    
//!    step 1: create 64 bit frf and fref numbers
//!    
//!    step 2: calculate O (output divider)
//!    
//!    step 3: get current R-divider setting
//!    
//!    step 4: calculate frf*O*R
//!               max bit count/resolution: 33b+3b+5b= 41b
//!
//!    step 5: calculate N(10b), using value from step 1
//!               N = (int) frf*O*R/fref
//!               max bit count/resolution: 41b-23b = 18b
//!
//!    step 6: calculate NUM (18b)
//! - NUM = (int) [262144 * (frf*O*R/fref -N)]
//! - NUM = (int) [2^18   * (frf*O*R/fref -N)]
//!
//!    to get the correct value the above calculation are performed like this
//! - NUM =((int)((frf*O*R/fref)<<23) - N<<23 + rounding) >> 5,  where << & >> are  bit shift left, right
//! - note 1: << 23b was chosen, because step one use 41b,  41b +23b = 64b (max number for 64 bit math)
//!    - note 2: >> 5 was chosen because 23-5 = 2^18, which is the same as multiplying by 262144
//!    - note 3: the rounding variable is equivalent to adding 0.5 to the NUM number.  the integer operation always
//!    rounds down, so adding a 0.5 to the number before rounding down ensures the closest value is selected.
//!    In this function the lower 5 bits of  (frf*O*R/fref)<<23) - N<<23 (possible variable 0-31) 
//!    are check to see if they are >=16.
//!    If they are then 16 is added to this number before performing the int and >>5 functions.
//! @return void                            
void LTC6947_set_frf();
        

/* ------------------------------------------------------------------------- */ 
//! sets globals LTC6947_Fref_MHz and LTC6947_Fref_Hz
//! @return void
void set_LTC6947_global_fref(unsigned long fref_MHz, unsigned long fref_Hz);


/* ------------------------------------------------------------------------- */ 
//! sets globals LTC6947_Frf_MHz and LTC6947_Frf_Hz
//! @return void
void set_LTC6947_global_frf(unsigned long frf_MHz, unsigned long frf_Hz);

/* ------------------------------------------------------------------------- */ 
//! sets globals LTC6947_VCO_Max_Freq_MHz, LTC6947_VCO_Max_Freq_Hz, LTC6947_VCO_Min_Freq_MHz and LTC6947_VCO_Min_Freq_Hz
//! @return void
void set_LTC6947_global_vcolim(unsigned long fvco_max_MHz, unsigned long fvco_max_Hz, unsigned long fvco_min_MHz, unsigned long fvco_min_Hz);


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_Fref_MHz 
//! @return LTC6947_Fref_MHz
unsigned long get_LTC6947_global_fref_MHz();


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_Fref_Hz 
//! @return LTC6947_Fref_Hz
unsigned long get_LTC6947_global_fref_Hz();


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_Frf_MHz 
//! @return LTC6947_Frf_MHz
unsigned long get_LTC6947_global_frf_MHz();


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_Frf_Hz 
//! @return LTC6947_Frf_Hz
unsigned long get_LTC6947_global_frf_Hz();


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_VCO_Max_Freq_MHz 
//! @return LTC6947_VCO_Max_Freq_MHz
unsigned long get_LTC6947_global_VCO_MAX_MHz();


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_VCO_Min_Freq_MHz 
//! @return LTC6947_VCO_Min_Freq_MHz
unsigned long get_LTC6947_global_VCO_MIN_MHz();


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_VCO_Max_Freq_Hz 
//! @return LTC6947_VCO_Max_Freq_Hz
unsigned long get_LTC6947_global_VCO_MAX_Hz();


/* ------------------------------------------------------------------------- */ 
//! returns global LTC6947_VCO_Min_Freq_Hz 
//! @return LTC6947_VCO_Min_Freq_Hz
unsigned long get_LTC6947_global_VCO_MIN_Hz();
    
    
/* ------------------------------------------------------------------------- */                                
//!   create a 64 bit Hz number from
//!   32 bit xxxx MHz number and 32 bit yyy yyy Hz number.
//!   A) if an < 2^32 bits:
//!      - an(upper 32b) = 0;
//!      - an(lower 32b) = MHzPart(32b)*1MHz + HzPart (32b)
//!
//!   B) if an > 2^32 bits (4,294,967,296):
//!     - an(upper 32b) = 1
//!     - an(lower 32b) = ((MHzPart-4294)*1MHz+HzPart)-967296
//! @return void                            
void HZto64(unsigned long  an[],            //!< 64 bit number, 1x2 32 bit array
            unsigned long MHzPart,          //!< integer in MHZ 
            unsigned long HzPart            //!< integer in Hz                                
            );

/* ------------------------------------------------------------------------- */
//! Creates a equivalent 64 bit number from 2 32 bit numbers
//! - an[0]=bigPart    upper 32 bits
//! - an[1]=littlePart lower 32 bits
//! @return void
void init64(unsigned long an[],        //!< 64 bit number, 1x2 32 bit array
            unsigned long bigPart,     //!< upper 32 bits
            unsigned long littlePart   //!< lower 32 bits
           );

/* ------------------------------------------------------------------------- */
//! Single Bit shift left of equivalent 64 bit number (an[] = an[]<<1)
//! @return void
void shl64(unsigned long  an[]         //!<  an[] = an[]<<1
          );

/* ------------------------------------------------------------------------- */
//! Multi Bit shift left of equivalent 64 bit number (an[] = an[]<<shiftnum)
//! @return void
void shl64by(unsigned long  an[],     //!<  an[] = an[]<<shiftnum
             uint8_t shiftnum         //!<  number of bits to shift left
            );

/* ------------------------------------------------------------------------- */
//! Single Bit shift right of equivalent 64 bit number (an[] = an[]<<1)
//! @return void
void shr64(unsigned long  an[]        //!<  an[] = an[]>>shiftnum
          );

/* ------------------------------------------------------------------------- */
//! Multi Bit shift right of equivalent 64 bit number (an[] = an[]>>shiftnum)
//! @return void
void shr64by(unsigned long  an[],     //!<  an[] = an[]>>shiftnum
             uint8_t shiftnum         //!<  number of bits to shift right
            );

/* ------------------------------------------------------------------------- */
//! 64 bit Add ann to an (an[] = an[] + ann[])
//! @return void
void add64(unsigned long  an[],      //!<  64 bit number, in 1x2 32bit array
           unsigned long  ann[]      //!<  64 bit number, in 1x2 32bit array
          );

/* ------------------------------------------------------------------------- */
//! 64 bit Subtract ann from an (an[] = an[] - ann[])
//! @return void
void sub64(unsigned long  an[],      //!<  64 bit number, in 1x2 32bit array
           unsigned long  ann[]      //!<  64 bit number, in 1x2 32bit array
          );

/* ------------------------------------------------------------------------- */
//! 64 bit, if an == ann, then true
//! @return true, if an==ann; false, if an<>ann
boolean eq64(unsigned long  an[],    //!<  64 bit number, in 1x2 32bit array
             unsigned long  ann[]    //!<  64 bit number, in 1x2 32bit array
            );

/* ------------------------------------------------------------------------- */
//! 64 bit, if an < ann, then true
//! @return true, if an<ann; false, if an=>ann
boolean lt64(unsigned long  an[],     //!<  64 bit number, in 1x2 32bit array
             unsigned long  ann[]     //!<  64 bit number, in 1x2 32bit array
            );

/* ------------------------------------------------------------------------- */
//! 64 bit Divide,   num=num/div
//! @return void
void div64(unsigned long num[],    //!<  numerator: 64 bit number, in 1x2 32bit array
           unsigned long den[]     //!<  denominator: 64 bit number, in 1x2 32bit array
          );


/* ------------------------------------------------------------------------- */
//! 64 bit multiply,   an=an*ann
//! @return void
void mul64(unsigned long an[],     //!<  64 bit number, in 1x2 32bit array
           unsigned long ann[]     //!<  64 bit number, in 1x2 32bit array
          );
 
/* ------------------------------------------------------------------------- */
//! Prints HEX representation of 64 bit an
//! @return void 
void prt(unsigned long  an[]       //!<  64 bit number, in 1x2 32bit array
        ); 

#endif  // LTC6947_H

Download LTC6947 - Linduino.CPP File

/*!
    LTC6947: Ultralow Noise and Spurious 0.35GHz to 6GHz FracN Synthesizer 

@verbatim

The LTC®6947 is a high performance, low noise, 6GHz
phase-locked loop (PLL), including a reference divider,
phase-frequency detector (PFD), ultralow noise charge
pump, fractional feedback divider, and VCO output divider.

The fractional divider uses an advanced, 4th order ΔΣ
modulator which provides exceptionally low spurious
levels. This allows wide loop bandwidths, producing
extremely low integrated phase noise values.

The programmable VCO output divider, with a range of 1
through 6, extends the output frequency range.

@endverbatim


http://www.linear.com/product/LTC6947

http://www.linear.com/product/LTC6947#demoboards

REVISION HISTORY
$Revision: 3018 $
$Date: 2014-12-01 15:53:20 -0800 (Mon, 01 Dec 2014) $

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.
*/

//! @defgroup LTC6947 LTC6947: Ultralow Noise and Spurious 0.35GHz to 6GHz FracN Synthesizer 

/*! @file
    @ingroup LTC6947
    Library for LTC6947: Ultralow Noise and Spurious 0.35GHz to 6GHz FracN Synthesizer 
*/

#include <stdint.h>
#include <Arduino.h>
#include "Linduino.h"
#include "UserInterface.h"
#include "LT_SPI.h"
#include "LTC6947.h"
#include <SPI.h>

uint8_t LTC6947_reg[LTC6947_NUM_REGADDR];               //!< number of LTC6947 spi addresses  
uint8_t LTC6947_spi_map[(LTC6947_NUM_REGFIELD+1)][4];   //!< LTC6947 spi map, stores MSB address location, MSB bit location, field length in bits, and R or RW capability

unsigned long LTC6947_Fref_MHz = 100;                   //!< Default Fref frequency - MHz portion (xxx);  Fref = xxx, yyy,yyy
unsigned long LTC6947_Fref_Hz = 0;                      //!< Default Fref frequency - Hz portion (yyy,yyy);  Fref = x,xxx, yyy,yyy
unsigned long LTC6947_Frf_MHz = 2415;                   //!< Default Frf frequency - MHz portion (xxxx);  Frf = x,xxx, yyy,yyy
unsigned long LTC6947_Frf_Hz  = 0;                      //!< Default Frf frequency - Hz portion (yyy,yyy);  Frf = x,xxx, yyy,yyy
unsigned long LTC6947_VCO_Max_Freq_MHz = 2536;          //!< Max Vco frequency for default on board VCO  - MHz portion (xxxx);  Fvco max = xxx, yyy,yyy
unsigned long LTC6947_VCO_Min_Freq_MHz = 2328;          //!< Min Vco frequency for default on board VCO - MHz portion (xxxx);  Fvco min = x,xxx, yyy,yyy
unsigned long LTC6947_VCO_Max_Freq_Hz = 0;              //!< Max Vco frequency for default on board VCO  - Hz portion (yyy,yyy);  Fvco max = x,xxx, yyy,yyy
unsigned long LTC6947_VCO_Min_Freq_Hz = 0;              //!< Min Vco frequency for default on board VCO  - Hz portion (yyy,yyy);  Fvco min= x,xxx, yyy,yyy

unsigned long zero64[]={0,0}; //!< for 64bit math functions

/* -------------------------------------------------------------------------
  FUNCTION: LTC6947_read
  - reads 8 bit Data field to LTC6947.
  - has to shift data by one bit to account for RW bit
 -------------------------------------------------------------------------- */
uint8_t LTC6947_read(uint8_t cs, int8_t address) {
int8_t address_shift;
LT_union_int16_2bytes rx;
  
address_shift =(address << 1) | 0x01; // shift to left to account for R/W bit, set bit high for read
spi_transfer_word(cs, address_shift<<8 , &rx.LT_uint16);
  
LTC6947_reg[address]=rx.LT_byte[0];
return(rx.LT_byte[0]);
}


/* -------------------------------------------------------------------------
  FUNCTION: LTC6947_read_field
  For SPI FIELDS located in 1 or multiple address location
  - reads specific address locations
  - identifies and returns specific field in question
    - can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
--------------------------------------------------------------------------- */
 long LTC6947_read_field(uint8_t cs, uint8_t address, uint8_t MSB_loc, uint8_t numbits){
 int bit_shift, i, num_reg;
 long field_val, maskbits, pow2;

num_reg=0;
field_val=0;
// determines how many register are used
do {
   bit_shift = (MSB_loc+1)- (numbits-num_reg*8);   // determines bit_shift for last register location
   field_val=LTC6947_read(cs, (address+num_reg))+(field_val<<8);  // reads current address locations, shifts previous address location 8 bits
   num_reg++;
}while ((bit_shift<0) && (num_reg<4));
  
// creates a bit mask for complete word, 
maskbits = 1;
pow2=1;
for(i=1, maskbits=1;i<numbits; i++) {
   pow2=pow2*2;
   maskbits = maskbits+pow2;
   }
 
field_val=(field_val >>bit_shift) &maskbits; 
return field_val;
}

/* -------------------------------------------------------------------------
  FUNCTION: get_LTC6947_SPI_FIELD
  For SPI FIELDS
  - reads specific address locations
  - identifies and returns specific field in question
    - can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
--------------------------------------------------------------------------- */
long get_LTC6947_SPI_FIELD(uint8_t cs, uint8_t f) {
 
return LTC6947_read_field(cs, LTC6947_spi_map[f][ADDRx], LTC6947_spi_map[f][DxMSB], LTC6947_spi_map[f][NUMBITS]);
}
 
/* -------------------------------------------------------------------------
  FUNCTION: LTC6947_write
  - writes 8 bit Data field to LTC6947.
  - has to shift data by one bit to account for RW bit
--------------------------------------------------------------------------- */
void LTC6947_write(uint8_t cs, uint8_t address, uint8_t Data) {
LT_union_int16_2bytes rx;
  
address=address << 1; // shift to left to account for R/W bit
spi_transfer_word(cs, (address<<8) | Data, &rx.LT_uint16);
}


 /* -------------------------------------------------------------------------
  FUNCTION: LTC6947_write_field
  For SPI FIELDS
  - reads specific address location
  - identifies and returns specific field in question
    - can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
---------------------------------------------------------------------------- */
uint8_t LTC6947_write_field(uint8_t cs, long field_data, uint8_t address, uint8_t MSB_loc, uint8_t numbits){
long current_content, desired_content, reg_val;
int LSB_loc, i, j, num_reg, bit_shift;
long temp_arr[32];
  
for(i=0; i<32 ; i++) temp_arr[i]=0;   // init temp_arr
  
// read data in current address location and put in a bit array
num_reg=0;
current_content=0;
do {
   bit_shift=(MSB_loc+1)-(numbits-num_reg*8);
   current_content=LTC6947_read(cs, (address+num_reg)) + (current_content<<8);

   num_reg++;
} while((bit_shift<0) && (num_reg<4));
for(i=0; i<(8*num_reg); i++) {temp_arr[i]=(current_content>>i) & 1; }
  
// exchange current bits with desired bits
LSB_loc = 8*(num_reg-1)+MSB_loc-numbits+1;
for(i=LSB_loc, j=0; i<=(MSB_loc+(num_reg-1)*8); i++, j++){
   temp_arr[i] = (field_data>>j) &1;
   } // end of for loop
    
// reconstruct bits into an integer
desired_content = 0;
for(i=0; i<(8*num_reg); i++) {
   desired_content = desired_content | (temp_arr[i]<<i);
   } // end of for loop
    
// write new field value to part
for(i=0; i<num_reg; i++) {
   reg_val = (desired_content >> 8*(num_reg-1-i)) & 0xff;
   LTC6947_write(cs, (address+i), reg_val);
   } // end of for loop
} // end of LTC6947_write_field
 
 
/* -------------------------------------------------------------------------
   FUNCTION: get_LTC6947_REGSIZE
   - returns # of addresses in parts register map (array size)
---------------------------------------------------------------------------- */
uint8_t get_LTC6947_REGSIZE(){
return sizeof(LTC6947_reg);
}
 
 
/* -------------------------------------------------------------------------
   FUNCTION: get_LTC6947_SPI_FIELD_NUMBITS
   - returns the number of bits for a given field name in the SPI map
---------------------------------------------------------------------------- */
uint8_t get_LTC6947_SPI_FIELD_NUMBITS(uint8_t f) {
return LTC6947_spi_map[f][NUMBITS];
}
 
 
/* -------------------------------------------------------------------------
   FUNCTION: get_LTC6947_SPI_FIELD_RW
   - returns if the given field name is (0)read/write or (1)read_only field
---------------------------------------------------------------------------- */
uint8_t get_LTC6947_SPI_FIELD_RW(uint8_t f) {
return LTC6947_spi_map[f][R_ONLY];
}
 
 
/* -------------------------------------------------------------------------
   FUNCTION: set_LTC6947_SPI_FIELD
   For SPI FIELDS 
   - reads specific address location
   - identifies and returns specific field in question
   - can handle SPI fields in multiple addresses, if MSB bit is in the lower number address
---------------------------------------------------------------------------- */
void set_LTC6947_SPI_FIELD(uint8_t cs, uint8_t f, long field_data) {
LTC6947_write_field(cs, field_data, LTC6947_spi_map[f][ADDRx], LTC6947_spi_map[f][DxMSB], LTC6947_spi_map[f][NUMBITS]);
}
 

/* -------------------------------------------------------------------------
   FUNCTION: set_LTC6947_ALLREGS
   - writes data to all registers at once
--------------------------------------------------------------------------- */
void set_LTC6947_ALLREGS(uint8_t cs, uint8_t reg01, uint8_t reg02, uint8_t reg03, uint8_t reg04, uint8_t reg05, uint8_t reg06, uint8_t reg07, uint8_t reg08, uint8_t reg09, uint8_t reg0A, uint8_t reg0B, uint8_t reg0C, uint8_t reg0D) {
uint8_t i;
 
LTC6947_reg[1] = reg01;
LTC6947_reg[2] = reg02;
LTC6947_reg[3] = reg03;
LTC6947_reg[4] = reg04;
LTC6947_reg[5] = reg05;
LTC6947_reg[6] = reg06; 
LTC6947_reg[7] = reg07;
LTC6947_reg[8] = reg08;
LTC6947_reg[9] = reg09;
LTC6947_reg[10] = reg0A;
LTC6947_reg[11] = reg0B;
LTC6947_reg[12] = reg0C; 
LTC6947_reg[13] = reg0D;
   
for(i=1; i<14; i++)  LTC6947_write(cs, i, LTC6947_reg[i]);
} // end of set_LTC6947_ALLREGS
 
 
/* -------------------------------------------------------------------------
   FUNCTION: LTC6947_init
   - initializes the SPI MAP
   - for ease of programming there is spreadsheet that automates this some.
----------------------------------------------------------------------------*/
void LTC6947_init() { 
   
// spi map    
LTC6947_spi_map[LTC6947_AUTORST][ADDRx]=0x03;  LTC6947_spi_map[LTC6947_AUTORST][DxMSB]= 2;   LTC6947_spi_map[LTC6947_AUTORST][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_BST][ADDRx]=0x0b;      LTC6947_spi_map[LTC6947_BST][DxMSB]= 7;       LTC6947_spi_map[LTC6947_BST][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CP][ADDRx]=0x0c;       LTC6947_spi_map[LTC6947_CP][DxMSB]= 2;        LTC6947_spi_map[LTC6947_CP][NUMBITS]= 3;
LTC6947_spi_map[LTC6947_CPCHI][ADDRx]=0x0d;       LTC6947_spi_map[LTC6947_CPCHI][DxMSB]= 7;     LTC6947_spi_map[LTC6947_CPCHI][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPCLO][ADDRx]=0x0d;    LTC6947_spi_map[LTC6947_CPCLO][DxMSB]= 6;     LTC6947_spi_map[LTC6947_CPCLO][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPDN][ADDRx]=0x0d;     LTC6947_spi_map[LTC6947_CPDN][DxMSB]= 0;      LTC6947_spi_map[LTC6947_CPDN][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPINV][ADDRx]=0x0d;       LTC6947_spi_map[LTC6947_CPINV][DxMSB]= 4;     LTC6947_spi_map[LTC6947_CPINV][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPLE][ADDRx]=0x04;     LTC6947_spi_map[LTC6947_CPLE][DxMSB]= 3;      LTC6947_spi_map[LTC6947_CPLE][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPMID][ADDRx]=0x0d;       LTC6947_spi_map[LTC6947_CPMID][DxMSB]= 5;     LTC6947_spi_map[LTC6947_CPMID][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPRST][ADDRx]=0x0d;       LTC6947_spi_map[LTC6947_CPRST][DxMSB]= 2;     LTC6947_spi_map[LTC6947_CPRST][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPUP][ADDRx]=0x0d;     LTC6947_spi_map[LTC6947_CPUP][DxMSB]= 1;      LTC6947_spi_map[LTC6947_CPUP][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_CPWIDE][ADDRx]=0x0d;   LTC6947_spi_map[LTC6947_CPWIDE][DxMSB]= 3;    LTC6947_spi_map[LTC6947_CPWIDE][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_DITHEN][ADDRx]=0x03;   LTC6947_spi_map[LTC6947_DITHEN][DxMSB]= 1;    LTC6947_spi_map[LTC6947_DITHEN][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_FILT][ADDRx]=0x0b;     LTC6947_spi_map[LTC6947_FILT][DxMSB]= 6;      LTC6947_spi_map[LTC6947_FILT][NUMBITS]= 2;
LTC6947_spi_map[LTC6947_INTN][ADDRx]=0x03;     LTC6947_spi_map[LTC6947_INTN][DxMSB]= 0;      LTC6947_spi_map[LTC6947_INTN][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_LDOEN][ADDRx]=0x04;    LTC6947_spi_map[LTC6947_LDOEN][DxMSB]= 2;     LTC6947_spi_map[LTC6947_LDOEN][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_LDOV][ADDRx]=0x04;     LTC6947_spi_map[LTC6947_LDOV][DxMSB]= 1;      LTC6947_spi_map[LTC6947_LDOV][NUMBITS]= 2;
LTC6947_spi_map[LTC6947_LKCT][ADDRx]=0x0c;     LTC6947_spi_map[LTC6947_LKCT][DxMSB]= 4;      LTC6947_spi_map[LTC6947_LKCT][NUMBITS]= 2;
LTC6947_spi_map[LTC6947_LKWIN][ADDRx]=0x0c;    LTC6947_spi_map[LTC6947_LKWIN][DxMSB]= 7;     LTC6947_spi_map[LTC6947_LKWIN][NUMBITS]= 3;
LTC6947_spi_map[LTC6947_LOCK][ADDRx]=0x00;     LTC6947_spi_map[LTC6947_LOCK][DxMSB]= 2;      LTC6947_spi_map[LTC6947_LOCK][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_ND][ADDRx]=0x06;       LTC6947_spi_map[LTC6947_ND][DxMSB]= 1;        LTC6947_spi_map[LTC6947_ND][NUMBITS]= 10;
LTC6947_spi_map[LTC6947_NUM][ADDRx]=0x08;      LTC6947_spi_map[LTC6947_NUM][DxMSB]= 5;       LTC6947_spi_map[LTC6947_NUM][NUMBITS]= 18;
LTC6947_spi_map[LTC6947_OD][ADDRx]=0x0b;       LTC6947_spi_map[LTC6947_OD][DxMSB]= 2;        LTC6947_spi_map[LTC6947_OD][NUMBITS]= 3;
LTC6947_spi_map[LTC6947_OMUTE][ADDRx]=0x02;    LTC6947_spi_map[LTC6947_OMUTE][DxMSB]= 1;     LTC6947_spi_map[LTC6947_OMUTE][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_PART][ADDRx]=0x0e;     LTC6947_spi_map[LTC6947_PART][DxMSB]= 3;      LTC6947_spi_map[LTC6947_PART][NUMBITS]= 4;
LTC6947_spi_map[LTC6947_PDALL][ADDRx]=0x02;    LTC6947_spi_map[LTC6947_PDALL][DxMSB]= 7;     LTC6947_spi_map[LTC6947_PDALL][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_PDFN][ADDRx]=0x02;     LTC6947_spi_map[LTC6947_PDFN][DxMSB]= 3;      LTC6947_spi_map[LTC6947_PDFN][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_PDOUT][ADDRx]=0x02;    LTC6947_spi_map[LTC6947_PDOUT][DxMSB]= 4;     LTC6947_spi_map[LTC6947_PDOUT][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_PDPLL][ADDRx]=0x02;    LTC6947_spi_map[LTC6947_PDPLL][DxMSB]= 6;     LTC6947_spi_map[LTC6947_PDPLL][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_POR][ADDRx]=0x02;      LTC6947_spi_map[LTC6947_POR][DxMSB]= 0;       LTC6947_spi_map[LTC6947_POR][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_RD][ADDRx]=0x06;       LTC6947_spi_map[LTC6947_RD][DxMSB]= 7;        LTC6947_spi_map[LTC6947_RD][NUMBITS]= 5;
LTC6947_spi_map[LTC6947_REV][ADDRx]=0x0e;      LTC6947_spi_map[LTC6947_REV][DxMSB]= 7;       LTC6947_spi_map[LTC6947_REV][NUMBITS]= 4;
LTC6947_spi_map[LTC6947_RFO][ADDRx]=0x0b;      LTC6947_spi_map[LTC6947_RFO][DxMSB]= 4;       LTC6947_spi_map[LTC6947_RFO][NUMBITS]= 2;
LTC6947_spi_map[LTC6947_RSTFN][ADDRx]=0x0a;    LTC6947_spi_map[LTC6947_RSTFN][DxMSB]= 1;     LTC6947_spi_map[LTC6947_RSTFN][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_SEED][ADDRx]=0x05;     LTC6947_spi_map[LTC6947_SEED][DxMSB]= 7;      LTC6947_spi_map[LTC6947_SEED][NUMBITS]= 8;
LTC6947_spi_map[LTC6947_THI][ADDRx]=0x00;      LTC6947_spi_map[LTC6947_THI][DxMSB]= 1;       LTC6947_spi_map[LTC6947_THI][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_TLO][ADDRx]=0x00;      LTC6947_spi_map[LTC6947_TLO][DxMSB]= 0;       LTC6947_spi_map[LTC6947_TLO][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_UNLOK][ADDRx]=0x00;    LTC6947_spi_map[LTC6947_UNLOK][DxMSB]= 5;     LTC6947_spi_map[LTC6947_UNLOK][NUMBITS]= 1;
LTC6947_spi_map[LTC6947_x][ADDRx]=0x01;        LTC6947_spi_map[LTC6947_x][DxMSB]= 5;         LTC6947_spi_map[LTC6947_x][NUMBITS]= 6;
  
LTC6947_spi_map[LTC6947_AUTORST][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_BST][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CP][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPCHI][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPCLO][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPDN][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPINV][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPLE][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPMID][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPRST][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPUP][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_CPWIDE][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_DITHEN][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_FILT][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_INTN][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_LDOEN][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_LDOV][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_LKCT][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_LKWIN][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_LOCK][R_ONLY]= 1;
LTC6947_spi_map[LTC6947_ND][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_NUM][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_OD][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_OMUTE][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_PART][R_ONLY]= 1;
LTC6947_spi_map[LTC6947_PDALL][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_PDFN][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_PDOUT][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_PDPLL][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_POR][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_RD][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_REV][R_ONLY]= 1;
LTC6947_spi_map[LTC6947_RFO][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_RSTFN][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_SEED][R_ONLY]= 0;
LTC6947_spi_map[LTC6947_THI][R_ONLY]= 1;
LTC6947_spi_map[LTC6947_TLO][R_ONLY]= 1;
LTC6947_spi_map[LTC6947_UNLOK][R_ONLY]= 1;
LTC6947_spi_map[LTC6947_x][R_ONLY]= 0;

} // end of LTC6947_init

void set_LTC6947_global_fref(unsigned long fref_MHz, unsigned long fref_Hz){
LTC6947_Fref_MHz=fref_MHz;
LTC6947_Fref_Hz=fref_Hz;
}

void set_LTC6947_global_frf(unsigned long frf_MHz, unsigned long frf_Hz){
LTC6947_Frf_MHz=frf_MHz;
LTC6947_Frf_Hz=frf_Hz;
}

void set_LTC6947_global_vcolim(unsigned long fvco_max_MHz, unsigned long fvco_max_Hz, unsigned long fvco_min_MHz, unsigned long fvco_min_Hz){
LTC6947_VCO_Max_Freq_MHz=fvco_max_MHz;
LTC6947_VCO_Max_Freq_Hz=fvco_max_Hz;
LTC6947_VCO_Min_Freq_MHz=fvco_min_MHz;
LTC6947_VCO_Min_Freq_Hz=fvco_min_Hz;
}



unsigned long get_LTC6947_global_fref_MHz(){
return LTC6947_Fref_MHz;
}

unsigned long get_LTC6947_global_fref_Hz(){
return LTC6947_Fref_Hz;
}

unsigned long get_LTC6947_global_frf_MHz(){
return LTC6947_Frf_MHz;
}

unsigned long get_LTC6947_global_frf_Hz(){
return LTC6947_Frf_Hz;
}

unsigned long get_LTC6947_global_VCO_MAX_MHz(){
return LTC6947_VCO_Max_Freq_MHz;
}

unsigned long get_LTC6947_global_VCO_MIN_MHz(){
return LTC6947_VCO_Min_Freq_MHz;
}

unsigned long get_LTC6947_global_VCO_MAX_Hz(){
return LTC6947_VCO_Max_Freq_Hz;
}

unsigned long get_LTC6947_global_VCO_MIN_Hz(){
return LTC6947_VCO_Min_Freq_Hz;
}

/* -------------------------------------------------------------------------
   FUNCTION: calc_odiv
   - calculates the output divider setting based on the frf and on board
     VCO frequencies of LTC6947
   - @return odiv = 1-6 for valid setting, 999 as invalid frequency
---------------------------------------------------------------------------- */  
unsigned long LTC6947_calc_odiv(unsigned long frf[2]){
unsigned long odiv, i;
unsigned long max_fout64[2];
unsigned long min_fout64[2];
unsigned long temp_fout[2];
unsigned long temp_i[2];
boolean valid_input=false;


HZto64(max_fout64,LTC6947_VCO_Max_Freq_MHz,LTC6947_VCO_Max_Freq_Hz);
HZto64(min_fout64,LTC6947_VCO_Min_Freq_MHz,LTC6947_VCO_Min_Freq_Hz);
  
// verify desired frequency falls within a divider range (1-6)  
valid_input=false;
for(i=1; i<=6; i++) {
   init64(temp_i,0L,i);
   temp_fout[0] = frf[0];
   temp_fout[1] = frf[1];
   mul64(temp_fout,temp_i);
   if (lt64(temp_fout,max_fout64) || eq64(temp_fout, max_fout64)) {  // same as frf*i <= max_fout
      if (lt64(min_fout64,temp_fout) || eq64(temp_fout, min_fout64)) {// same as frf*i >= min_fout
         valid_input=true;
         odiv=i;
         }
      }
   } // end of for loop
 
if (valid_input == false) odiv= 999L;
return odiv;

} // end of LTC6947_calc_odiv

/* -------------------------------------------------------------------------
   FUNCTION: LTC6947_set_frf
   Calculates the integer (N), fractional (NUM) and output divider (OD) SPI values
   using self created 64bit math functions.
   
  Datasheet equations
    fvco = fpfd*(N + F)
    frf  = fvco/O
    fpfd = fref/R
    F=NUM/2^18 = NUM/262144
    
    can be modified to the following equations
    N   = (int) (fvco/fpfd)  = (int) frf*O*R/fref
    NUM = (int) [262144 * (frf*O*R/fref -N)]
    
    where
    N = ndiv, O= odiv, NUM=fracN_num  in the code below
    
    Linduino One (Arduino Uno) is limited to 32 bit floats/double/long.
    32 bit math functions will create rounding errors with the above equations, 
    tha can result in frequency errors.
    Therefore, the following code uses self created 64bit functions for 64bit integer math.
    
    frf (33 bits) LTC6947-4 max frf/fvco = 6.4GHZ, which is 23 bit number (2^33 = 8.59G)
    fref (23 bits) LTC6947 min fref = 10MHz, which is a 23 bit number (2^23 = 8.3M)
    O   (3 bits)
    R   (5 bits)
    
    step 1: create 64 bit frf and fref numbers
    
    step 2: calculate O (output divider)
    
    step 3: get current R-divider setting
    
    step 4: calculate frf*O*R
               max bit count/resolution: 33b+3b+5b= 41b
    step 5: calculate N(10b), using value from step 1
               N = (int) frf*O*R/fref
               max bit count/resolution: 41b-23b = 18b
    step 6: calculate NUM (18b)
               NUM = (int) [262144 * (frf*O*R/fref -N)]
                   = (int) [2^18   * (frf*O*R/fref -N)]
                to get the correct value the above calculation are performed like this
                   =  ((int)((frf*O*R/fref)<<23) - N<<23 + rounding) >> 5,  where << & >> are  bit shift left, right
                      * note << 23b was chosen, because step one use 41b,  41b +23b = 64b (max number for 64 bit math)
                      ** note >> 5 was chosen because 23-5 = 2^18, which is the same as multiplying by 262144
                      *** the rounding variable is equivalent to adding 0.5 to the NUM number.  the integer operation always
                          rounds down, so adding a 0.5 to the number before rounding down ensures the closest value is 
                          selected.
                          In this function the lower 5 bits of  (frf*O*R/fref)<<23) - N<<23 (possible variable 0-31) 
                          are check to see if they are >=16.
                          If they are then 16 is added to this number before performing the int and >>5 functions.
---------------------------------------------------------------------------- */
void LTC6947_set_frf(){
unsigned long frf_MHz, frf_Hz, fref_MHz, fref_Hz, odiv, rdiv, ndiv, fracN_num, frac_num_remainder;
unsigned long N64[2], NUM64[2], R64[2], O64[2], temp_long[2];
char buffer[100];
unsigned long frf[2], frf_act[2];
unsigned long fref[2];
unsigned long temp_math[2];
unsigned long frf_rdiv_odiv[2];
unsigned long frf_rdiv_odiv_int[2];
unsigned long roundup[2];

/* step 1: create 64 bit frf and fref numbers
   32 bit xxxx MHz number and 32 bit yyy yyy Hz number. */
frf_MHz=LTC6947_Frf_MHz;
frf_Hz=LTC6947_Frf_Hz;
HZto64(frf, frf_MHz, frf_Hz);

fref_MHz=LTC6947_Fref_MHz;
fref_Hz=LTC6947_Fref_Hz;
HZto64(fref,fref_MHz,fref_Hz);

// step 2: calculate O (output divider)
odiv=LTC6947_calc_odiv(frf);

// step 3: get current R-divider setting
rdiv=get_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_RD);    // reads selected field

// step 3: calculate frf*O*R
frf_rdiv_odiv[0]=0;
frf_rdiv_odiv[1]=odiv*rdiv;
mul64(frf_rdiv_odiv, frf);  // odiv*rdiv*frf
frf_rdiv_odiv_int[0]=frf_rdiv_odiv[0];  // copy odiv*rdiv*frf to another variable
frf_rdiv_odiv_int[1]=frf_rdiv_odiv[1];

// step 4: calculate N(10b), using value from step 3; N = (int) frf*O*R/fref
temp_math[0]=fref[0];   // copy fref to temp variable for math operation
temp_math[1]=fref[1];
div64(frf_rdiv_odiv_int, temp_math);   // frf_rdiv_odiv_int= [(frf*odiv*rdiv)]/fref  -->  int(fvco/fpfd)
ndiv=frf_rdiv_odiv_int[1]; 

// step 5: calculate NUM (18b), NUM = (int) [262144 * (frf*O*R/fref -N)]
// SEE notes in function header for step 5
// ((int)((frf*O*R/fref)<<23) - N<<23 + rounding) >> 5,  where << & >> are  bit shift left, right
shl64by(frf_rdiv_odiv,23);
div64(frf_rdiv_odiv,  fref);    // frf_rdiv_odiv     -->  [(frf*odiv*rdiv)<<23]/fref  

shl64by(frf_rdiv_odiv_int,23); // frf_rdiv_odiv_int  -->  [(int)((frf*odiv*rdiv)/fref)] <<23

sub64(frf_rdiv_odiv,frf_rdiv_odiv_int);

// NUM is a 18 bit number in the spi register
// At this point in the program it is represented by 23 bits
// if the lower 5 bits are >=16 (16/31), 
// then add 16 to the frac_num_remainder.  After the bits are
// shifted down 5 bits this will be close to added 0.5 bits.
frac_num_remainder=(frf_rdiv_odiv[1] & 31L);
if(frac_num_remainder >= 16L)  {
   roundup[0]=0L;
   roundup[1]=16L;
   add64(frf_rdiv_odiv,roundup);  
   }
 
// shift NUM to get desired 18 bit number for SPI map.
shr64by(frf_rdiv_odiv,5);
fracN_num=frf_rdiv_odiv[1];

// program part and print out results to screen
set_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_OD,odiv);    // programs output divider
Serial.print("OD = ");
Serial.println(odiv);

Serial.print("RD = ");
Serial.println(rdiv);

set_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_ND,ndiv);    // programs N-divider
Serial.print(F("ND = "));
Serial.println(ndiv);

if(fracN_num > 0L) {
  set_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_INTN,0L);    // programs fractional mode
  set_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_NUM,fracN_num);    // programs NUM
  if( (ndiv<35) || (ndiv>1019) ) Serial.print(F("N DIV set to invalid setting - REFER TO DATASHEET\n"));
  }
else {
  set_LTC6947_SPI_FIELD(LTC6947_CS,LTC6947_INTN,1L);    // programs INTN
  Serial.print(F("When NUM=0, changes to Integer Mode (NUM can not be 0)\n"));
  if( (ndiv<32) || (ndiv>1023) ) Serial.print(F("N DIV set to invalid setting - REFER TO DATASHEET\n"));
  }  
Serial.print(F("NUM = "));
Serial.println(fracN_num);


/////  calculate actual fout here and print out
frf_act[0]=fref[0];
frf_act[1]=fref[1];
N64[0]=0; NUM64[0]=0; R64[0]=0; O64[0]=0;
N64[1]=ndiv;
NUM64[1]=fracN_num;
R64[1]=rdiv;
O64[1]=odiv;

shl64by(N64,18);
add64(N64,NUM64);    // (N*262144 +NUM)    
div64(frf_act,R64);  // fref/rdiv (or fpfd)
mul64(frf_act,N64);  // (N*262144 +NUM)*fpdf
div64(frf_act,O64);  // ((N*262144 +NUM)*fpdf)/odiv
shr64by(frf_act,17); 
if(frf_act[0]==0) {  // no 32 bit overflow case
   Serial.print(F("Actual Output Frequency (closest available) is "));
   Serial.print(frf_act[1]);
   Serial.println("Hz");
   }
else {  // overflow case
   temp_math[0]=frf_act[0];
   temp_math[1]=frf_act[1];
   temp_long[0]=0;
   temp_long[1]=OneMHz;
   div64(temp_math,temp_long);  // frf/1e6
   Serial.print(F("Actual Output Frequency (closest available) is "));
   Serial.print(temp_math[1]);
   Serial.print("MHz + ");
   temp_long[0]=0;
   temp_long[1]=OneMHz;
   mul64(temp_math,temp_long);  // int(frf/1e6)*1e6
   sub64(frf_act,temp_math);    //  frf-int(frf/1e6)*1e6
   Serial.print(frf_act[1]);
   Serial.println("Hz");
   }
}


/* -------------------------------------------------------------------------
   FUNCTION: prt
   Prints HEX representation of 64 bit an
---------------------------------------------------------------------------- */
void prt(unsigned long  an[]){
  Serial.print(an[0],HEX);
  Serial.print(" ");
 Serial.println(an[1],HEX);
}


/* -------------------------------------------------------------------------
   FUNCTION: init64
   Creates a equivalent 64 bit number from 2 32 bit numbers
    an[0]=bigPart    //upper 32 bits
    an[1]=littlePart //lower 32 bits
---------------------------------------------------------------------------- */
void init64(unsigned long  an[], unsigned long bigPart, unsigned long littlePart ){
  an[0]=bigPart;
  an[1]=littlePart;
}

/* -------------------------------------------------------------------------
   FUNCTION: HZto64
   create a 64 bit Hz number from
   32 bit xxxx MHz number and 32 bit yyy yyy Hz number.
   A) if an < 2^32 bits 
      an(upper 32b) = 0
      an(lower 32b) = MHzPart(32b)*1MHz + HzPart (32b)
   B) if an > 2^32 bits (4,294,967,296) 
     an(upper 32b) = 1
     an(lower 32b) = ((MHzPart-4294)*1MHz+HzPart)-967296
---------------------------------------------------------------------------- */
void HZto64(unsigned long  an[], unsigned long MHzPart, unsigned long HzPart ){

if((MHzPart>4295) || ((MHzPart==4294) && (HzPart>=967296))){
  an[0]=1L;                                        // upper 32 bits 
  an[1] =(MHzPart-4294L)*OneMHz + HzPart-967296L;  // lower 32 bits
  }
else {
  an[0] = 0;                        // upper 32 bits
  an[1] = MHzPart*OneMHz+HzPart;    // lower 32 bits
  }
}

/* -------------------------------------------------------------------------
   FUNCTION: shl64
   Single Bit shift left of equivalent 64 bit number (an[] = an[]<<1)
---------------------------------------------------------------------------- */
void shl64(unsigned long  an[]){
 an[0] <<= 1; 
 if(an[1] & 0x80000000)
   an[0]++; 
 an[1] <<= 1; 
}


/* -------------------------------------------------------------------------
   FUNCTION: shr64
   Single Bit shift right of equivalent 64 bit number (an[] = an[]>>1)
---------------------------------------------------------------------------- */
void shr64(unsigned long  an[]){
 an[1] >>= 1; 
 if(an[0] & 0x1)
   an[1]+=0x80000000; 
 an[0] >>= 1; 
}


/* -------------------------------------------------------------------------
   FUNCTION: shl64by
   Multi Bit shift left of equivalent 64 bit number (an[] = an[]<<shiftnum)
---------------------------------------------------------------------------- */
void shl64by(unsigned long  an[], uint8_t shiftnum){
uint8_t i;

for(i=0; i<shiftnum; i++) {
   an[0] <<= 1; 
   if(an[1] & 0x80000000)
      an[0]++; 
   an[1] <<= 1; 
   }
}


/* -------------------------------------------------------------------------
   FUNCTION: shr64by
   Multi Bit shift right of equivalent 64 bit number (an[] = an[]>>shiftnum)
---------------------------------------------------------------------------- */
void shr64by(unsigned long  an[], uint8_t shiftnum){
uint8_t i;

for(i=0; i<shiftnum; i++) {
   an[1] >>= 1; 
   if(an[0] & 0x1)
      an[1]+=0x80000000; 
   an[0] >>= 1; 
   }
}


/* -------------------------------------------------------------------------
   FUNCTION: add64
   64 bit Add ann to an (an[] = an[] + ann[])
---------------------------------------------------------------------------- */
void add64(unsigned long  an[], unsigned long  ann[]){
  an[0]+=ann[0];
  if(an[1] + ann[1] < ann[1])
    an[0]++;
  an[1]+=ann[1];
}


/* -------------------------------------------------------------------------
   FUNCTION: sub64
   64 bit Subtract ann from an (an[] = an[] - ann[])
---------------------------------------------------------------------------- */
void sub64(unsigned long  an[], unsigned long  ann[]){
  an[0]-=ann[0];
  if(an[1] < ann[1]){
    an[0]--;
  }
  an[1]-= ann[1];
}


/* -------------------------------------------------------------------------
   FUNCTION: eq64
   64 bit, if an == ann, then true
---------------------------------------------------------------------------- */
boolean eq64(unsigned long  an[], unsigned long  ann[]){
  return (an[0]==ann[0]) && (an[1]==ann[1]);
}


/* -------------------------------------------------------------------------
   FUNCTION: lt64
   64 bit, if an < ann, then true
---------------------------------------------------------------------------- */
boolean lt64(unsigned long  an[], unsigned long  ann[]){
  if(an[0]>ann[0]) return false;
  return (an[0]<ann[0]) || (an[1]<ann[1]);
}


/* -------------------------------------------------------------------------
   FUNCTION: div64
   64 bit Divide,   num=num/div
---------------------------------------------------------------------------- */
void div64(unsigned long num[], unsigned long den[]){
  unsigned long quot[2];
  unsigned long qbit[2];
  unsigned long tmp[2];
  init64(quot,0,0);
  init64(qbit,0,1);

  if (eq64(num, zero64)) {  //numerator 0, call it 0
    init64(num,0,0);
    return;            
  }

  if (eq64(den, zero64)) { //numerator not zero, denominator 0, infinity in my book.
    init64(num,0xffffffff,0xffffffff);
    return;            
  }

  init64(tmp,0x80000000,0);
  while(lt64(den,tmp)){
    shl64(den);
    shl64(qbit);
  } 
  
  while(!eq64(qbit,zero64)){
    if(lt64(den,num) || eq64(den,num)){
      sub64(num,den);
      add64(quot,qbit);
    }
    shr64(den);
    shr64(qbit);
  }

  //remainder now in num, but using it to return quotient for now  
  init64(num,quot[0],quot[1]); 
}


/* -------------------------------------------------------------------------
   FUNCTION: mul64
   64 bit multiply,   an=an*ann
---------------------------------------------------------------------------- */
void mul64(unsigned long an[], unsigned long ann[]){
  unsigned long p[2] = {0,0};
  unsigned long y[2] = {ann[0], ann[1]};
  while(!eq64(y,zero64)) {
    if(y[1] & 1) 
      add64(p,an);
    shl64(an);
    shr64(y);
  }
  init64(an,p[0],p[1]);
} 

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