Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board

DC1795A LTC6950: 1.4GHz Low Phase Noise, Low Jitter PLL with Clock Distribution. More...

Detailed Description

DC1795A LTC6950: 1.4GHz Low Phase Noise, Low Jitter PLL with Clock Distribution.

  Setup:
    Set the terminal baud rate to 115200 and select the newline terminator.
    Refer to Demo Manual DC1795A.
    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.


Command Description:

                             *****Main Menu*****
    1-  Load Default Settings- Loads the SPI map that is identical to file
        LTC6950_ALL_CHAN_250MHz.clkset that is supplied with the ClockWizard and mentioned
        in the DC1795A user's manual.  It assumes a 100MHz reference input, a 1GHz VCO input
        and the default DC1795A BOM.  It should output a 250MHz signal on all outputs.

        ** If you want to use a different loop filter, reference frequency or different
        register settings.  Please use ClockWizard for the loop filter design and initial
        device setup.  The register settings from ClockWizard 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 LTC6950.  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

http://www.linear.com/product/LTC6950

http://www.linear.com/product/LTC6950#demoboards

Copyright 2018(c) Analog Devices, Inc.

All rights reserved.

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Definition in file DC1795A.ino.

Go to the source code of this file.

Functions

static void print_title ()
 Prints the title block when program first starts. More...
 
static void print_prompt ()
 Prints main menu. More...
 
static void menu_1_load_default_settings ()
 Menu 1: Load Default SPI Register Settings This function loads the register settings referenced in the DC1795A demo manual's quick start section. More...
 
static void menu_2_RW_to_reg_addresss ()
 Menu 2: Reads and/or Writes the SPI register address This function reads and displays all SPI register address settings in HEX format. More...
 
static void menu_3_RW_to_reg_field ()
 Menu 3: Reads and/or Writes individual SPI fields This function provides the user with a list of all SPI fields. More...
 
static void menu_4_set_frf ()
 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. More...
 
static void menu_5_store_settings ()
 Store PLL settings to nonvolatile EEPROM on demo board. More...
 
static void menu_6_restore_settings ()
 Read stored PLL settings from nonvolatile EEPROM on demo board. More...
 
static void setup ()
 Initialize Linduino. More...
 
static void loop ()
 Repeats Linduino loop. More...
 
long field_menu_RW (long field_val, char field_name[], uint8_t f)
 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. More...
 
static void LTC6950_VCO_Freq_Verification ()
 verifies VCO frequency is within datasheet specifications More...
 
static void LTC6950_Ref_Freq_Verification ()
 verifies reference frequency is within datasheet specifications More...
 
static void LTC6950_Fout_Freq_Verification ()
 

Variables

static uint8_t ref_out = 0
 Used to keep track of reference out status. More...
 
static int8_t demo_board_connected
 Demo Board Name stored in QuikEval EEPROM. More...
 
static uint8_t First_Run =0
 if first time through loop = 0, otherwise=1 More...
 

Function Documentation

◆ field_menu_RW()

long field_menu_RW ( long  field_val,
char  field_name[],
uint8_t  f 
)

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.

Returns
field value (user input) that will be written to part
Parameters
field_valcurrent state of the selected field
field_nameSPI Field name selected
fSPI field identifier identifies selected fields information in SPI MAP arrays

Definition at line 292 of file DC1795A.ino.

◆ loop()

static void loop ( void  )
static

Repeats Linduino loop.

Returns
void

Definition at line 154 of file DC1795A.ino.

◆ LTC6950_Fout_Freq_Verification()

static void LTC6950_Fout_Freq_Verification ( )
static

Definition at line 938 of file DC1795A.ino.

◆ LTC6950_Ref_Freq_Verification()

static void LTC6950_Ref_Freq_Verification ( )
static

verifies reference frequency is within datasheet specifications

Definition at line 890 of file DC1795A.ino.

◆ LTC6950_VCO_Freq_Verification()

static void LTC6950_VCO_Freq_Verification ( )
static

verifies VCO frequency is within datasheet specifications

Definition at line 823 of file DC1795A.ino.

◆ menu_1_load_default_settings()

static void menu_1_load_default_settings ( )
static

Menu 1: Load Default SPI Register Settings This function loads the register settings referenced in the DC1795A demo manual's quick start section.

The register settings loaded are the same as CLOCK WIZARDS clkset files LTC6950_PECL0_250MHz.clkset The setting loaded with this function assume the LTC6950's reference is set to 100MHz, the VCO input is set to 1GHz and the DC1795A's BOM has not been modified.

Returns
void

Definition at line 215 of file DC1795A.ino.

◆ menu_2_RW_to_reg_addresss()

static void menu_2_RW_to_reg_addresss ( )
static

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
  • ....
  • 21- ADDR15 = 0x04
  • 22- ADDR16 = 0x65 (read only)
  • 0 - Return to Main Menu
  • Enter a command (1-21 to modify register, or '0' to return to Main Menu):
    Returns
    void

Definition at line 237 of file DC1795A.ino.

◆ menu_3_RW_to_reg_field()

static void menu_3_RW_to_reg_field ( )
static

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-CMSINV 26-IBIAS3 51-PD_OUT2
  • 2-CP 27-INV_ST1 52-PD_OUT3
  • ....
  • 23-IBIAS0 48-PD_DIV4 73-UNLOCK *
  • 24-IBIAS1 49-PD_OUT0
  • 25-IBIAS2 50-PD_OUT1
  • 0 - Return to Main Menu
  • * = READ ONLY FIELD
  • Enter a command (1-73 to modify register, or '0' to return to Main Menu):
    Returns
    void

Definition at line 353 of file DC1795A.ino.

◆ menu_4_set_frf()

static void menu_4_set_frf ( )
static

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

Returns
void

Definition at line 1008 of file DC1795A.ino.

◆ menu_5_store_settings()

static void menu_5_store_settings ( )
static

Store PLL settings to nonvolatile EEPROM on demo board.

Returns
void

Definition at line 1030 of file DC1795A.ino.

◆ menu_6_restore_settings()

static void menu_6_restore_settings ( )
static

Read stored PLL settings from nonvolatile EEPROM on demo board.

Returns
void

Definition at line 1056 of file DC1795A.ino.

◆ print_prompt()

static void print_prompt ( )
static

Prints main menu.

Definition at line 1118 of file DC1795A.ino.

◆ print_title()

static void print_title ( void  )
static

Prints the title block when program first starts.

Definition at line 1093 of file DC1795A.ino.

◆ setup()

static void setup ( void  )
static

Initialize Linduino.

Returns
void

Definition at line 127 of file DC1795A.ino.

Variable Documentation

◆ demo_board_connected

int8_t demo_board_connected
static

Demo Board Name stored in QuikEval EEPROM.

Definition at line 120 of file DC1795A.ino.

◆ First_Run

uint8_t First_Run =0
static

if first time through loop = 0, otherwise=1

Definition at line 121 of file DC1795A.ino.

◆ ref_out

uint8_t ref_out = 0
static

Used to keep track of reference out status.

Definition at line 119 of file DC1795A.ino.