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Linduino
1.3.0
Linear Technology Arduino-Compatible Demonstration Board
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Linear Technology DC1678A Demonstration Board. More...
Linear Technology DC1678A Demonstration Board.
LTC2654: Quad SPI 16-/12-Bit Rail-to-Rail DACs with 10ppm/C Max 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: DC1678A-A, DC1678A-B, DC1678A-C, DC1678A-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. 7- Calibrate DAC: Use a precision voltmeter to obtain and enter VOUT readings taken with different DAC codes. Set reference mode FIRST, as values are stored separately for internal and external reference mode. Entries are used to calculate the closest code to send to the DAC to achieve an entered voltage. 8- Enable / Disable calibration: Switch between stored calibration values and defaults. Calibration parameters are stored separately for internal and external reference modes. Ideal calibration will be used if the calibration parameter valid key is not set. USER INPUT DATA FORMAT: decimal : 1024 hex : 0x400 octal : 02000 (leading 0 "zero") binary : B10000000000 float : 1024.0
http://www.linear.com/product/LTC2654
http://www.linear.com/product/LTC2654#demoboards
Copyright 2018(c) Analog Devices, Inc.
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
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 DC1678A.ino.
Go to the source code of this file.
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static int8_t | restore_calibration () |
Read stored calibration parameters from nonvolatile EEPROM on demo board. More... | |
static void | store_calibration () |
Store measured calibration parameters to 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 LTC2654_lsb, int16_t LTC2654_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 | calibrate_dac (uint8_t index) |
Calibrate the selected DAC using a voltmeter. 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 void | menu_7_calibrate_dacs () |
Calibrate all DACs by measuring two known outputs. More... | |
static void | menu_8_enable_calibration () |
Enable / Disable calibration. More... | |
static void | setup () |
Initialize Linduino. More... | |
static void | loop () |
Repeats Linduino loop. More... | |
Macros | |
#define | EEPROM_CAL_KEY_INT 0x5678 |
Calibration associated with internal reference. More... | |
#define | EEPROM_CAL_KEY_EXT 0x9ABC |
Calibration associated with external reference. More... | |
#define | REF_INTERNAL LTC2654_CMD_INTERNAL_REFERENCE |
Stored reference state is Internal. More... | |
#define | REF_EXTERNAL LTC2654_CMD_EXTERNAL_REFERENCE |
Stored reference state is External. More... | |
#define | STORED_REF_STATE_BASE EEPROM_CAL_STATUS_ADDRESS |
Base address of the stored reference state. More... | |
#define | INT_CAL_VALID_BASE STORED_REF_STATE_BASE + 2 |
Base address of the "internal ref calibration valid" flag. More... | |
#define | INT_CAL_PARAMS_BASE INT_CAL_VALID_BASE + 2 |
Base address of the internal ref calibration parameters. More... | |
#define | EXT_CAL_VALID_BASE INT_CAL_PARAMS_BASE + 32 |
Base address of the "external ref calibration valid" flag. More... | |
#define | EXT_CAL_PARAMS_BASE EXT_CAL_VALID_BASE + 2 |
Base address of the external ref calibration parameters. More... | |
#define | EXT_REF_V_BASE EXT_CAL_PARAMS_BASE + 32 |
Base address of the stored external reference voltage. 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 |
Tells whether to set internal or external reference. More... | |
static float | reference_voltage |
Reference voltage, either internal or external. More... | |
static int16_t | LTC2654_offset [5] |
DAC offset - index 4 for "all DACs". More... | |
static float | LTC2654_lsb [5] |
The LTC2654 lsb - index 4 for "all DACs". More... | |
const uint8_t | address_map [5] = {LTC2654_DAC_A, LTC2654_DAC_B, LTC2654_DAC_C, LTC2654_DAC_D, LTC2654_DAC_ALL} |
Lookup table for DAC address. More... | |
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Calibrate the selected DAC using a voltmeter.
The routine does a linear curve fit given two data points.
Definition at line 602 of file DC1678A.ino.
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Get code to send to DAC directly, in decimal, hex, or binary.
Definition at line 540 of file DC1678A.ino.
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Get voltage from user input, calculate DAC code based on lsb, offset.
Definition at line 526 of file DC1678A.ino.
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Repeats Linduino loop.
Definition at line 197 of file DC1678A.ino.
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Select which DAC to operate on.
Definition at line 251 of file DC1678A.ino.
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Write data to input register, but do not update DAC output.
Definition at line 263 of file DC1678A.ino.
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Write data to DAC register (which updates output immediately)
Definition at line 276 of file DC1678A.ino.
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Update DAC with data that is stored in input register, power up if sleeping.
Definition at line 289 of file DC1678A.ino.
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Power down DAC.
Definition at line 296 of file DC1678A.ino.
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Set reference mode and store to EEPROM.
Definition at line 303 of file DC1678A.ino.
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Calibrate all DACs by measuring two known outputs.
Definition at line 327 of file DC1678A.ino.
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Enable / Disable calibration.
Use with caution - behavior is undefined if you enable calibration and an actual calibration cycle has not been performed.
Definition at line 340 of file DC1678A.ino.
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Prints main menu.
Definition at line 568 of file DC1678A.ino.
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Prints the title block when program first starts.
Definition at line 553 of file DC1678A.ino.
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Prompt user to enter a voltage or digital code to send to DAC.
Definition at line 510 of file DC1678A.ino.
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Read stored calibration parameters from nonvolatile EEPROM on demo board.
Definition at line 368 of file DC1678A.ino.
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Initialize Linduino.
Definition at line 179 of file DC1678A.ino.
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Store measured calibration parameters to nonvolatile EEPROM on demo board.
Definition at line 482 of file DC1678A.ino.
#define EEPROM_CAL_KEY_EXT 0x9ABC |
Calibration associated with external reference.
Definition at line 120 of file DC1678A.ino.
#define EEPROM_CAL_KEY_INT 0x5678 |
Calibration associated with internal reference.
Definition at line 119 of file DC1678A.ino.
#define EXT_CAL_PARAMS_BASE EXT_CAL_VALID_BASE + 2 |
Base address of the external ref calibration parameters.
Definition at line 133 of file DC1678A.ino.
#define EXT_CAL_VALID_BASE INT_CAL_PARAMS_BASE + 32 |
Base address of the "external ref calibration valid" flag.
Definition at line 132 of file DC1678A.ino.
#define EXT_REF_V_BASE EXT_CAL_PARAMS_BASE + 32 |
Base address of the stored external reference voltage.
Definition at line 134 of file DC1678A.ino.
#define INT_CAL_PARAMS_BASE INT_CAL_VALID_BASE + 2 |
Base address of the internal ref calibration parameters.
Definition at line 131 of file DC1678A.ino.
#define INT_CAL_VALID_BASE STORED_REF_STATE_BASE + 2 |
Base address of the "internal ref calibration valid" flag.
Definition at line 130 of file DC1678A.ino.
#define REF_EXTERNAL LTC2654_CMD_EXTERNAL_REFERENCE |
Stored reference state is External.
Definition at line 126 of file DC1678A.ino.
#define REF_INTERNAL LTC2654_CMD_INTERNAL_REFERENCE |
Stored reference state is Internal.
Definition at line 125 of file DC1678A.ino.
#define STORED_REF_STATE_BASE EEPROM_CAL_STATUS_ADDRESS |
Base address of the stored reference state.
Definition at line 129 of file DC1678A.ino.
anonymous enum |
Used to keep track to print voltage or print code.
Enumerator | |
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PROMPT_VOLTAGE | 0 |
PROMPT_CODE | 1 |
Definition at line 172 of file DC1678A.ino.
const uint8_t address_map[5] = {LTC2654_DAC_A, LTC2654_DAC_B, LTC2654_DAC_C, LTC2654_DAC_D, LTC2654_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 169 of file DC1678A.ino.
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Set to 1 if the board is connected.
Definition at line 156 of file DC1678A.ino.
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The LTC2654 lsb - index 4 for "all DACs".
Definition at line 163 of file DC1678A.ino.
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DAC offset - index 4 for "all DACs".
Definition at line 162 of file DC1678A.ino.
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Tells whether to set internal or external reference.
Definition at line 158 of file DC1678A.ino.
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Reference voltage, either internal or external.
Definition at line 161 of file DC1678A.ino.
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