Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board

Linear Technology DC1466 Demonstration Board. More...

Detailed Description

Linear Technology DC1466 Demonstration Board.

LTC2636: Octal 12-/10-/8-Bit SPI VOUT DACs with 10ppm/°C Reference.

Linear Technology DC1488 Demonstration Board. LTC2634: Quad 12-/10-/8-Bit SPI VOUT DACs with 10ppm/°C Reference.

NOTES
  Setup:
   Set the terminal baud rate to 115200 and select the newline terminator.
   The program displays calculated voltages which are based on the voltage
   of the reference used, be it internal or external. A precision voltmeter
   is needed to verify the actual measured voltages against the calculated
   voltage displayed. If an external reference is used, a precision voltage
   source is required to apply the external reference voltage. A
   precision voltmeter is also required to measure the external reference
   voltage. No external power supply is required. Any assembly option
   may be used: DC1466A-A, DC1466A-B, DC1466A-C, DC1466A-D.


  Explanation of Commands:
   1- Select DAC: Select one of four DACs to test : A, B, C, D.

   2- Write to DAC input register: Value is stored in the DAC for updating
      later, allowing multiple channels to be updated at once, either
      through a software "Update All" command or by asserting the LDAC# pin.
      User will be prompted to enter either a code in hex or decimal, or a
      voltage. If a voltage is entered, a code will be calculated based on
      the active scaling and reference parameters - ideal values if no
      calibration was ever stored.

   3- Write and Update: Similar to item 1, but DAC is updated immediately.

   4- Update DAC: Copies the value from the input register into the DAC
      Register. Note that a "write and update" command writes the code to
      BOTH the input register and DAC register, so subsequent "update"
      commands will simply re-copy the same data (no change in output.)

   5- Power Down DAC: Disable DAC output. Power supply current is reduced.
      DAC code present in DAC registers at time of shutdown are preserved.

   6- Set reference mode, either internal or external: Selecting external
      mode prompts for the external reference voltage, which is used directly
      if no individual DAC calibration is stored. The selection and entered
      voltage are stored to EEPROM so it is persistent across reset / power cycles.

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

http://www.linear.com/product/LTC2636 http://www.linear.com/product/LTC2634

http://www.linear.com/product/LTC2636#demoboards http://www.linear.com/product/LTC2634#demoboards

Copyright 2018(c) Analog Devices, Inc.

All rights reserved.

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  • 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.
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THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, 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.

Definition in file DC1466.ino.

Go to the source code of this file.

Functions

static void restore_calibration ()
 Read stored calibration parameters from nonvolatile EEPROM on demo board. More...
 
static void print_title ()
 Prints the title block when program first starts. More...
 
static void print_prompt (int16_t selected_dac)
 Prints main menu. More...
 
static int16_t prompt_voltage_or_code ()
 Prompt user to enter a voltage or digital code to send to DAC. More...
 
static uint16_t get_voltage (float LTC2636_lsb, int16_t LTC2636_offset)
 Get voltage from user input, calculate DAC code based on lsb, offset. More...
 
static uint16_t get_code ()
 Get code to send to DAC directly, in decimal, hex, or binary. More...
 
static void menu_1_select_dac (int16_t *selected_dac)
 Select which DAC to operate on. More...
 
static void menu_2_write_to_input_register (int16_t selected_dac)
 Write data to input register, but do not update DAC output. More...
 
static void menu_3_write_and_update_dac (int16_t selected_dac)
 Write data to DAC register (which updates output immediately) More...
 
static void menu_4_update_power_up_dac (int16_t selected_dac)
 Update DAC with data that is stored in input register, power up if sleeping. More...
 
static void menu_5_power_down_dac (int16_t selected_dac)
 Power down DAC. More...
 
static void menu_6_set_reference_mode (void)
 Set reference mode and store to EEPROM. More...
 
static int8_t menu_7_calibrate_dacs ()
 Calibrate all DACs by measuring two known outputs. More...
 
static void setup ()
 Initialize Linduino. More...
 
static void loop ()
 Repeats Linduino loop. More...
 
static int8_t calibrate_dac (uint8_t index)
 Calibrate the selected DAC using a voltmeter. More...
 

Macros

#define REF_INTERNAL   LTC2636_CMD_INTERNAL_REFERENCE
 Stored reference state is Internal. More...
 
#define REF_EXTERNAL   LTC2636_CMD_EXTERNAL_REFERENCE
 Stored reference state is External. More...
 

Enumerations

enum  { PROMPT_VOLTAGE = 0, PROMPT_CODE = 1 }
 Used to keep track to print voltage or print code. More...
 

Variables

static uint8_t demo_board_connected
 Set to 1 if the board is connected. More...
 
static uint8_t shift_count
 The data align shift count. More...
 
static uint8_t reference_mode
 Tells whether to set internal or external reference. More...
 
static float reference_voltage
 Reference voltage, either internal or external. More...
 
static int16_t LTC2636_offset [9]
 DAC offset - index 8 for "all DACs". More...
 
static float LTC2636_lsb [9]
 The LTC2636 lsb - index 8 for "all DACs". More...
 
static uint8_t num_of_channels = 8
 
const uint8_t address_map [9] = {LTC2636_DAC_A, LTC2636_DAC_B, LTC2636_DAC_C, LTC2636_DAC_D, LTC2636_DAC_E, LTC2636_DAC_F, LTC2636_DAC_G, LTC2636_DAC_H, LTC2636_DAC_ALL}
 Lookup table for DAC address. More...
 

Function Documentation

◆ calibrate_dac()

static int8_t calibrate_dac ( uint8_t  index)
static

Calibrate the selected DAC using a voltmeter.

The routine does a linear curve fit given two data points.

Returns
ACK bit (0=acknowledge, 1=no acknowledge)

Definition at line 488 of file DC1466.ino.

◆ get_code()

static uint16_t get_code ( )
static

Get code to send to DAC directly, in decimal, hex, or binary.

Returns
code from user

Definition at line 473 of file DC1466.ino.

◆ get_voltage()

static uint16_t get_voltage ( float  LTC2636_lsb,
int16_t  LTC2636_offset 
)
static

Get voltage from user input, calculate DAC code based on lsb, offset.

Returns
the DAC code

Definition at line 459 of file DC1466.ino.

◆ loop()

static void loop ( void  )
static

Repeats Linduino loop.

Definition at line 175 of file DC1466.ino.

◆ menu_1_select_dac()

static void menu_1_select_dac ( int16_t *  selected_dac)
static

Select which DAC to operate on.

Definition at line 224 of file DC1466.ino.

◆ menu_2_write_to_input_register()

static void menu_2_write_to_input_register ( int16_t  selected_dac)
static

Write data to input register, but do not update DAC output.

Definition at line 236 of file DC1466.ino.

◆ menu_3_write_and_update_dac()

static void menu_3_write_and_update_dac ( int16_t  selected_dac)
static

Write data to DAC register (which updates output immediately)

Definition at line 248 of file DC1466.ino.

◆ menu_4_update_power_up_dac()

static void menu_4_update_power_up_dac ( int16_t  selected_dac)
static

Update DAC with data that is stored in input register, power up if sleeping.

Definition at line 262 of file DC1466.ino.

◆ menu_5_power_down_dac()

static void menu_5_power_down_dac ( int16_t  selected_dac)
static

Power down DAC.

Definition at line 275 of file DC1466.ino.

◆ menu_6_set_reference_mode()

static void menu_6_set_reference_mode ( void  )
static

Set reference mode and store to EEPROM.

Definition at line 288 of file DC1466.ino.

◆ menu_7_calibrate_dacs()

static int8_t menu_7_calibrate_dacs ( )
static

Calibrate all DACs by measuring two known outputs.

Returns
0

Definition at line 308 of file DC1466.ino.

◆ print_prompt()

static void print_prompt ( int16_t  selected_dac)
static

Prints main menu.

Definition at line 411 of file DC1466.ino.

◆ print_title()

static void print_title ( void  )
static

Prints the title block when program first starts.

Definition at line 396 of file DC1466.ino.

◆ prompt_voltage_or_code()

static int16_t prompt_voltage_or_code ( )
static

Prompt user to enter a voltage or digital code to send to DAC.

Returns
user input

Definition at line 443 of file DC1466.ino.

◆ restore_calibration()

static void restore_calibration ( )
static

Read stored calibration parameters from nonvolatile EEPROM on demo board.

Returns
void

Definition at line 321 of file DC1466.ino.

◆ setup()

static void setup ( void  )
static

Initialize Linduino.

Definition at line 157 of file DC1466.ino.

Macro Definition Documentation

◆ REF_EXTERNAL

#define REF_EXTERNAL   LTC2636_CMD_EXTERNAL_REFERENCE

Stored reference state is External.

Definition at line 117 of file DC1466.ino.

◆ REF_INTERNAL

#define REF_INTERNAL   LTC2636_CMD_INTERNAL_REFERENCE

Stored reference state is Internal.

Definition at line 116 of file DC1466.ino.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

Used to keep track to print voltage or print code.

Enumerator
PROMPT_VOLTAGE 

0

PROMPT_CODE 

1

Definition at line 150 of file DC1466.ino.

Variable Documentation

◆ address_map

Lookup table for DAC address.

Allows the "All DACs" address to be indexed right after DAC D in loops. This technique is very useful for devices with non-monotonic channel addresses. Map entered option 0..2 to DAC address

Definition at line 147 of file DC1466.ino.

◆ demo_board_connected

uint8_t demo_board_connected
static

Set to 1 if the board is connected.

Definition at line 136 of file DC1466.ino.

◆ LTC2636_lsb

float LTC2636_lsb[9]
static

The LTC2636 lsb - index 8 for "all DACs".

Definition at line 141 of file DC1466.ino.

◆ LTC2636_offset

int16_t LTC2636_offset[9]
static

DAC offset - index 8 for "all DACs".

Definition at line 140 of file DC1466.ino.

◆ num_of_channels

uint8_t num_of_channels = 8
static

Definition at line 142 of file DC1466.ino.

◆ reference_mode

uint8_t reference_mode
static

Tells whether to set internal or external reference.

Definition at line 138 of file DC1466.ino.

◆ reference_voltage

float reference_voltage
static

Reference voltage, either internal or external.

Definition at line 139 of file DC1466.ino.

◆ shift_count

uint8_t shift_count
static

The data align shift count.

For 12-bits=4, 10-bits=6, 8-bits=8

Definition at line 137 of file DC1466.ino.