| Linduino 1.3.0 Linear Technology Arduino-Compatible Demonstration Board

Functions | Macros | Enumerations | Variables
DC935A.ino File Reference
Digital-to-Analog Converters (DAC) » LTC2605: Octal 16-/14-/12-Bit Rail-to Rail DACs in 16-Lead SSOP

Linear Technology DC935A Demonstration Board LTC2605: Octal 16-/14-/12-Bit Rail-to Rail DACs in 16-Lead SSOP. More...

## Detailed Description

Linear Technology DC935A Demonstration Board LTC2605: Octal 16-/14-/12-Bit Rail-to Rail DACs in 16-Lead SSOP.

    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:

      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.

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

http://ww.linear.com/product/LTC2605

http://www.linear.com/product/LTC2605#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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Definition in file DC935A.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 (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 LTC2605_lsb, int16_t LTC2605_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 int8_t | calibrate_dac (uint8_t index)
static int8_t | menu_1_select_dac (int16_t *selected_dac)
| Select which DAC to operate on. More...
static int8_t | menu_2_write_to_input_register (int16_t selected_dac)
| Write data to input register, but do not update DAC output. More...
static int8_t | menu_3_write_and_update_dac (int16_t selected_dac)
| Write data to DAC register (which updates output immediately) More...
static int8_t | 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 int8_t | menu_5_power_down_dac (int16_t selected_dac)
| Power down DAC. More...
static void | setup ()
| Initialize Linduino. More...
static void | loop ()
| Repeats Linduino loop. More...

## Macros
#define | REF_INTERNAL LTC2605_CMD_INTERNAL_REFERENCE
| Stored reference state is Internal. More...
#define | REF_EXTERNAL LTC2605_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 = 0
| The data align shift count. More...
static uint8_t | reference_mode = REF_INTERNAL
| Tells whether to set internal or external reference. More...
static float | reference_voltage = 5
| Reference voltage, either internal or external. More...
static int16_t | LTC2605_offset = 0
| DAC offset. More...
static float | LTC2605_lsb = (reference_voltage / (pow(2,16) -1))
const uint8_t | address_map [9] = {LTC2605_DAC_A, LTC2605_DAC_B, LTC2605_DAC_C, LTC2605_DAC_D, LTC2605_DAC_E, LTC2605_DAC_F , LTC2605_DAC_G, LTC2605_DAC_H, LTC2605_DAC_ALL}
| Lookup table for DAC address. More...

## Function Documentation

## ◆ calibrate_dac()

static int8_t calibrate_dac | ( | uint8_t | index | ) |
| static

## ◆ get_code()

static uint16_t get_code | ( |  | ) |
| static

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

Returns
  DAC code

Definition at line 310 of file DC935A.ino.

## ◆ get_voltage()

static uint16_t get_voltage | ( | float | LTC2605_lsb,
|  | int16_t | LTC2605_offset
| ) |  |
| static

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

Returns
  voltage

Parameters

  LTC2605_lsb | the voltage LSB of the DAC
  LTC2605_offset | the Offset of the DAC

Definition at line 295 of file DC935A.ino.

## ◆ loop()

static void loop | ( | void |  | ) |
| static

Repeats Linduino loop.

Definition at line 160 of file DC935A.ino.

## ◆ menu_1_select_dac()

static int8_t menu_1_select_dac | ( | int16_t * | selected_dac | ) |
| static

Select which DAC to operate on.

Returns
  0

Parameters

  selected_dac | what DAC to operate on

Definition at line 206 of file DC935A.ino.

## ◆ menu_2_write_to_input_register()

static int8_t menu_2_write_to_input_register | ( | int16_t | selected_dac | ) |
| static

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

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

Parameters

  selected_dac | what DAC to operate on

Definition at line 220 of file DC935A.ino.

## ◆ menu_3_write_and_update_dac()

static int8_t menu_3_write_and_update_dac | ( | int16_t | selected_dac | ) |
| static

Write data to DAC register (which updates output immediately)

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

Parameters

  selected_dac | what DAC to operate on

Definition at line 238 of file DC935A.ino.

## ◆ menu_4_update_power_up_dac()

static int8_t 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.

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

Parameters

  selected_dac | what DAC to operate on

Definition at line 259 of file DC935A.ino.

## ◆ menu_5_power_down_dac()

static int8_t menu_5_power_down_dac | ( | int16_t | selected_dac | ) |
| static

Power down DAC.

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

Parameters

  selected_dac | what DAC to operate on

Definition at line 269 of file DC935A.ino.

## ◆ print_prompt()

static void print_prompt | ( | int16_t | selected_dac | ) |
| static

Prints main menu.

Parameters

  selected_dac | what DAC to operate on

Definition at line 341 of file DC935A.ino.

## ◆ print_title()

static void print_title | ( | void |  | ) |
| static

Prints the title block when program first starts.

Definition at line 326 of file DC935A.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
  prompt type

Definition at line 280 of file DC935A.ino.

## ◆ setup()

static void setup | ( | void |  | ) |
| static

Initialize Linduino.

Definition at line 145 of file DC935A.ino.

## Macro Definition Documentation

## ◆ REF_EXTERNAL

#define REF_EXTERNAL LTC2605_CMD_EXTERNAL_REFERENCE

Stored reference state is External.

Definition at line 105 of file DC935A.ino.

## ◆ REF_INTERNAL

#define REF_INTERNAL LTC2605_CMD_INTERNAL_REFERENCE

Stored reference state is Internal.

Definition at line 104 of file DC935A.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 138 of file DC935A.ino.

## Variable Documentation

## ◆ address_map

const uint8_t address_map[9] = {LTC2605_DAC_A, LTC2605_DAC_B, LTC2605_DAC_C, LTC2605_DAC_D, LTC2605_DAC_E, LTC2605_DAC_F , LTC2605_DAC_G, LTC2605_DAC_H, LTC2605_DAC_ALL}

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 135 of file DC935A.ino.

## ◆ demo_board_connected

uint8_t demo_board_connected
| static

Set to 1 if the board is connected.

Definition at line 122 of file DC935A.ino.

## ◆ LTC2605_lsb

float LTC2605_lsb = (reference_voltage / (pow(2,16) -1))
| static

Definition at line 129 of file DC935A.ino.

## ◆ LTC2605_offset

int16_t LTC2605_offset = 0
| static

DAC offset.

Definition at line 128 of file DC935A.ino.

## ◆ reference_mode

uint8_t reference_mode = REF_INTERNAL
| static

Tells whether to set internal or external reference.

Definition at line 124 of file DC935A.ino.

## ◆ reference_voltage

float reference_voltage = 5
| static

Reference voltage, either internal or external.

Definition at line 127 of file DC935A.ino.

## ◆ shift_count

uint8_t shift_count = 0
| static

The data align shift count.

For 16-bit=0, for 14 bits=2 for 12-bits=4

Definition at line 123 of file DC935A.ino.