Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board
DC935A.ino
Go to the documentation of this file.
1 /*!
2 Linear Technology DC935A Demonstration Board
3 LTC2605: Octal 16-/14-/12-Bit Rail-to Rail DACs in 16-Lead SSOP
4 
5 @verbatim
6 NOTES
7  Setup:
8  Set the terminal baud rate to 115200 and select the newline terminator.
9  The program displays calculated voltages which are based on the voltage
10  of the reference used, be it internal or external. A precision voltmeter
11  is needed to verify the actual measured voltages against the calculated
12  voltage displayed. If an external reference is used, a precision voltage
13  source is required to apply the external reference voltage. A precision
14  voltmeter is also required to measure the external reference voltage.
15  No external power supply is required. Any assembly option may be used:
16 
17  Explanation of Commands:
18  1- Select DAC: Select one of four DACs to test: A, B, C, D.
19 
20  2- Write to DAC input register: Value is stored in the DAC for updating
21  later, allowing multiple channels to be updated at once, either
22  through a software "Update All" command or by asserting the LDAC# pin.
23  User will be prompted to enter either a code in hex or decimal, or a
24  voltage. If a voltage is entered, a code will be calculated based on
25  the active scaling and reference parameters - ideal values if no
26  calibration was ever stored.
27 
28  3- Write and Update: Similar to item 1, but DAC is updated immediately.
29 
30  4- Update DAC: Copies the value from the input register into the DAC
31  Register. Note that a "write and update" command writes the code to
32  BOTH the input register and DAC register, so subsequent "update" commands
33  will simply re-copy the same data (no change in output).
34 
35  5- Power Down DAC: Disable DAC output. Power supply current is reduced. DAC
36  code present in DAC registers at time of shutdown are preserved.
37 
38 USER INPUT DATA FORMAT:
39  decimal : 1024
40  hex : 0x400
41  octal : 02000 (leading 0 "zero")
42  binary : B10000000000
43  float : 1024.0
44 
45 @endverbatim
46 http://ww.linear.com/product/LTC2605
47 
48 http://www.linear.com/product/LTC2605#demoboards
49 
50 
51 
52 Copyright 2018(c) Analog Devices, Inc.
53 
54 All rights reserved.
55 
56 Redistribution and use in source and binary forms, with or without
57 modification, are permitted provided that the following conditions are met:
58  - Redistributions of source code must retain the above copyright
59  notice, this list of conditions and the following disclaimer.
60  - Redistributions in binary form must reproduce the above copyright
61  notice, this list of conditions and the following disclaimer in
62  the documentation and/or other materials provided with the
63  distribution.
64  - Neither the name of Analog Devices, Inc. nor the names of its
65  contributors may be used to endorse or promote products derived
66  from this software without specific prior written permission.
67  - The use of this software may or may not infringe the patent rights
68  of one or more patent holders. This license does not release you
69  from the requirement that you obtain separate licenses from these
70  patent holders to use this software.
71  - Use of the software either in source or binary form, must be run
72  on or directly connected to an Analog Devices Inc. component.
73 
74 THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
75 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
76 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
77 IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
78 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
79 LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
80 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
81 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
82 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
83 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
84 
85 */
86 /*! @file
87  @ingroup LTC2605
88 */
89 
90 #include <Arduino.h>
91 #include <stdint.h>
92 #include "Linduino.h"
93 #include "LT_SPI.h"
94 #include "UserInterface.h"
95 #include "LT_I2C.h"
96 #include "QuikEval_EEPROM.h"
97 #include "LTC2605.h"
98 #include <Wire.h>
99 #include <SPI.h>
100 
101 // DAC Reference State
102 // Could have been 0 or 1. This allows you to use the
103 // variable "reference_mode" as the command argument to a write
104 #define REF_INTERNAL LTC2605_CMD_INTERNAL_REFERENCE //!< Stored reference state is Internal
105 #define REF_EXTERNAL LTC2605_CMD_EXTERNAL_REFERENCE //!< Stored reference state is External
106 
107 //Function Declaration
108 void print_title(); // Print the title block
109 void print_prompt(int16_t selected_dac); // Prompt the user for an input command
110 int16_t prompt_voltage_or_code();
111 uint16_t get_voltage(float LTC2605_lsb, int16_t LTC2605_offset);
112 uint16_t get_code();
113 int8_t calibrate_dac(uint8_t index); // Calibrate the selected DAC using a voltmeter. The routine does a linear curve fit given two data points.
114 
115 int8_t menu_1_select_dac(int16_t *selected_dac);
116 int8_t menu_2_write_to_input_register(int16_t selected_dac);
117 int8_t menu_3_write_and_update_dac(int16_t selected_dac);
118 int8_t menu_4_update_power_up_dac(int16_t selected_dac);
119 int8_t menu_5_power_down_dac(int16_t selected_dac);
120 
121 // Global variables
122 static uint8_t demo_board_connected; //!< Set to 1 if the board is connected
123 static uint8_t shift_count = 0; //!< The data align shift count. For 16-bit=0, for 14 bits=2 for 12-bits=4
124 static uint8_t reference_mode = REF_INTERNAL; //!< Tells whether to set internal or external reference
125 
126 // Global calibration variables
127 static float reference_voltage= 5; //!< Reference voltage, either internal or external
128 static int16_t LTC2605_offset = 0; //!< DAC offset
129 static float LTC2605_lsb = (reference_voltage / (pow(2,16) -1)); // least signifigant bit value of the dac
130 
131 // Constants
132 
133 //! Lookup table for DAC address. Allows the "All DACs" address to be indexed right after DAC D in loops.
134 //! This technique is very useful for devices with non-monotonic channel addresses.
136 
137 //! Used to keep track to print voltage or print code
138 enum
139 {
140  PROMPT_VOLTAGE = 0, /**< 0 */
141  PROMPT_CODE = 1 /**< 1 */
142 };
143 
144 //! Initialize Linduino
145 void setup()
146 // Setup the program
147 {
148  quikeval_I2C_init(); // Configure the EEPROM I2C port for 100khz
149  quikeval_I2C_connect(); // Connect I2C to main data port
150  Serial.begin(115200);
151  print_title();
152  //if(demo_board_connected)
153  demo_board_connected = true;
154  print_prompt(0);
156  Serial.flush();
157 }
158 
159 //! Repeats Linduino loop
160 void loop()
161 {
162  int8_t ack =0;
163  int16_t user_command;
164  static int16_t selected_dac =0; // The selected DAC to be updated (0=A, 1=B ... 9=All). Initialized to "A"
165  // the main control loop
166  if (demo_board_connected) // do nothing if board is not connected
167  {
168  if (Serial.available()) // check for user input
169  {
170  user_command = read_int();
171  Serial.println(user_command);
172  Serial.flush();
173  ack =0;
174  switch (user_command)
175  {
176  case 1:
177  ack |= menu_1_select_dac(&selected_dac);
178  break;
179  case 2:
180  ack |= menu_2_write_to_input_register(selected_dac);
181  break;
182  case 3:
183  ack |= menu_3_write_and_update_dac(selected_dac);
184  break;
185  case 4:
186  ack |= menu_4_update_power_up_dac(selected_dac);
187  break;
188  case 5:
189  ack |= menu_5_power_down_dac(selected_dac);
190  break;
191  default:
192  Serial.println("Incorrect Option");
193  break;
194  }
195  if (ack)Serial.println("I2C NACK received, check address\n");
196  Serial.println("\n*****************************************************************");
197  print_prompt(selected_dac);
198  }
199  }
200 }
201 
202 // Function Definitions
203 
204 //! Select which DAC to operate on
205 //! @return 0
206 int8_t menu_1_select_dac(int16_t *selected_dac) //!< what DAC to operate on
207 {
208  // Select a DAC to operate on
209  Serial.print("Select DAC to operate on (0=A, 1=B, 2=C, 3=D, 4=E, 5=F, 6=G, 7=H, 8=All)");
210  *selected_dac = read_int();
211  if (*selected_dac == 8)
212  Serial.println("All");
213  else
214  Serial.println(*selected_dac);
215  return(0);
216 }
217 
218 //! Write data to input register, but do not update DAC output
219 //! @return ACK bit (0=acknowledge, 1=no acknowledge)
220 int8_t menu_2_write_to_input_register(int16_t selected_dac) //!< what DAC to operate on
221 {
222  int8_t ack=0;
223  uint16_t dac_code;
224 
227  else
228  dac_code = get_code();
229 
230  Serial.print("DAC code transmitted: 0x");
231  Serial.println(dac_code,HEX);
232 
233  ack |= LTC2605_write(LTC2605_I2C_ADDRESS, LTC2605_CMD_WRITE, address_map[selected_dac], dac_code << shift_count);
234  return (ack);
235 }
236 //!Write data to DAC register (which updates output immediately)
237 //! @return ACK bit (0=acknowledge, 1=no acknowledge)
238 int8_t menu_3_write_and_update_dac(int16_t selected_dac) //!< what DAC to operate on
239 {
240  int8_t ack=0;
241  uint16_t dac_code;
242 
245  else
246  dac_code = get_code();
247  //Serial.print("lsb:");
248  //Serial.println(LTC2605_lsb);
249  Serial.print("DAC code transmitted: 0x");
250  Serial.println(dac_code,HEX);
251 
252 
254  return (ack);
255 }
256 
257 //! Update DAC with data that is stored in input register, power up if sleeping
258 //! @return ACK bit (0=acknowledge, 1=no acknowledge)
259 int8_t menu_4_update_power_up_dac(int16_t selected_dac) //!< what DAC to operate on
260 {
261  // Update DAC
262  int8_t ack=0;
263  ack |= LTC2605_write(LTC2605_I2C_ADDRESS, LTC2605_CMD_UPDATE, address_map[selected_dac], 0x0000);
264  return (ack);
265 }
266 
267 //! Power down DAC
268 //! @return ACK bit (0=acknowledge, 1=no acknowledge)
269 int8_t menu_5_power_down_dac(int16_t selected_dac) //!< what DAC to operate on
270 {
271  // Power down DAC
272  int8_t ack=0;
274  return (ack);
275 }
276 
277 
278 //! Prompt user to enter a voltage or digital code to send to DAC
279 //! @return prompt type
281 {
282  int16_t user_input;
283  Serial.print(F("Type 1 to enter voltage, 2 to enter code:"));
284  Serial.flush();
285  user_input = read_int();
286  Serial.println(user_input);
287 
288  if (user_input != 2)
289  return(PROMPT_VOLTAGE);
290  else
291  return(PROMPT_CODE);
292 }
293 //! Get voltage from user input, calculate DAC code based on lsb, offset
294 //! @return voltage
295 uint16_t get_voltage(float LTC2605_lsb, //!< the voltage LSB of the DAC
296  int16_t LTC2605_offset) //!< the Offset of the DAC
297 {
298  float dac_voltage;
299 
300  Serial.print(F("Enter Desired DAC output voltage: "));
301  dac_voltage = read_float();
302  Serial.print(dac_voltage);
303  Serial.println(" V");
304  Serial.flush();
305  return(LTC2605_voltage_to_code(dac_voltage, LTC2605_lsb, LTC2605_offset));
306 }
307 
308 //! Get code to send to DAC directly, in decimal, hex, or binary
309 //! @return DAC code
310 uint16_t get_code()
311 {
312  uint16_t returncode;
313  Serial.println("Enter Desired DAC Code");
314  Serial.print("(Format 32768, 0x8000, 0100000, or B1000000000000000): ");
315  returncode = (uint16_t) read_int();
316  Serial.print("0x");
317  Serial.println(returncode, HEX);
318  Serial.print("code corresponding to voltage: ");
319  Serial.print(LTC2605_code_to_voltage( returncode, LTC2605_lsb,LTC2605_offset));
320  Serial.println(" V");
321  Serial.flush();
322  return(returncode);
323 }
324 
325 //! Prints the title block when program first starts.
327 {
328  Serial.println("");
329  Serial.println(F("*****************************************************************"));
330  Serial.println(F("* DC935 Demonstration Program *"));
331  Serial.println(F("* *"));
332  Serial.println(F("* This program demonstrates how to send data to the LTC2605 *"));
333  Serial.println(F("* octo 16/14/12-bit DAC found on the DC935 demo board. *"));
334  Serial.println(F("* *"));
335  Serial.println(F("* Set the baud rate to 115200 and select the newline terminator.*"));
336  Serial.println(F("* *"));
337  Serial.println(F("*****************************************************************"));
338 }
339 
340 //! Prints main menu.
341 void print_prompt(int16_t selected_dac) //!< what DAC to operate on
342 {
343  Serial.println(F("\nCommand Summary:"));
344  Serial.println(F(" 1-Select DAC"));
345  Serial.println(F(" 2-Write to input register (no update)"));
346  Serial.println(F(" 3-Write and update DAC"));
347  Serial.println(F(" 4-Update / power up DAC"));
348  Serial.println(F(" 5-Power down DAC"));
349 
350 
351  Serial.println("\nPresent Values:");
352  Serial.print(" Selected DAC: ");
353  if (selected_dac != 4)
354  Serial.println((char) (selected_dac + 0x41));
355  else
356  Serial.println("All");
357  //Serial.print(" DAC Code: 0x");
358  // Serial.println(code[selected_dac], HEX);
359  // Serial.print(" Calculated DAC Output Voltage = ");
360  // Serial.print(voltage, 4);
361  // Serial.println(" V");
362  Serial.print(" DAC Reference: ");
364  Serial.println("Internal");
365  else
366  {
367  Serial.print(F("External "));
368  Serial.print(reference_voltage, 5);
369  Serial.println(F("V reference, please verify"));
370  Serial.print(F("Enter a command:"));
371 
372  }
373  Serial.flush();
374 }
static uint8_t demo_board_connected
Set to 1 if the board is connected.
Definition: DC935A.ino:122
#define LTC2605_DAC_G
Definition: LTC2605.h:213
#define LTC2605_CMD_NO_OPERATION
No operation.
Definition: LTC2605.h:187
#define LTC2605_CMD_UPDATE
Update (power up) DAC register n.
Definition: LTC2605.h:181
unsigned char user_command
static int16_t LTC2605_offset
DAC offset.
Definition: DC935A.ino:128
#define LTC2605_DAC_H
Definition: LTC2605.h:214
#define LTC2605_CMD_POWER_DOWN
Power down n.
Definition: LTC2605.h:183
static int8_t menu_2_write_to_input_register(int16_t selected_dac)
Write data to input register, but do not update DAC output.
Definition: DC935A.ino:220
const uint8_t address_map[9]
Lookup table for DAC address.
Definition: DC935A.ino:135
Header File for Linduino Libraries and Demo Code.
#define LTC2605_DAC_C
Definition: LTC2605.h:209
#define LTC2605_I2C_ADDRESS
Definition: LTC2605.h:169
static uint8_t shift_count
The data align shift count.
Definition: DC935A.ino:123
#define LTC2605_DAC_ALL
Definition: LTC2605.h:215
uint16_t LTC2605_voltage_to_code(float dac_voltage, float LTC2605_lsb, int16_t LTC2605_offset)
Calculate a LTC2605 DAC code given the desired output voltage.
Definition: LTC2605.cpp:85
static void setup()
Initialize Linduino.
Definition: DC935A.ino:145
#define LTC2605_CMD_WRITE_UPDATE
Write to input register n, update (power up) all.
Definition: LTC2605.h:182
static int8_t menu_3_write_and_update_dac(int16_t selected_dac)
Write data to DAC register (which updates output immediately)
Definition: DC935A.ino:238
static void print_title()
Prints the title block when program first starts.
Definition: DC935A.ino:326
#define LTC2605_DAC_F
Definition: LTC2605.h:212
QuikEval EEPROM Library.
static float reference_voltage
Reference voltage, either internal or external.
Definition: DC935A.ino:127
#define LTC2605_DAC_A
Definition: LTC2605.h:207
static uint16_t get_voltage(float LTC2605_lsb, int16_t LTC2605_offset)
Get voltage from user input, calculate DAC code based on lsb, offset.
Definition: DC935A.ino:295
LT_SPI: Routines to communicate with ATmega328P&#39;s hardware SPI port.
static float LTC2605_lsb
Definition: DC935A.ino:129
#define LTC2605_DAC_B
Definition: LTC2605.h:208
static void loop()
Repeats Linduino loop.
Definition: DC935A.ino:160
#define LTC2605_DAC_E
Definition: LTC2605.h:211
LT_I2C: Routines to communicate with ATmega328P&#39;s hardware I2C port.
#define LTC2605_DAC_D
Definition: LTC2605.h:210
#define LTC2605_CMD_WRITE
Write to input register n.
Definition: LTC2605.h:180
static int8_t menu_5_power_down_dac(int16_t selected_dac)
Power down DAC.
Definition: DC935A.ino:269
static int8_t calibrate_dac(uint8_t index)
int32_t read_int()
static int index
int8_t LTC2605_write(uint8_t i2c_address, uint8_t dac_command, uint8_t dac_address, uint16_t dac_code)
Write a 16-bit dac_code to the LTC2605.
Definition: LTC2605.cpp:76
float read_float()
float LTC2605_code_to_voltage(uint16_t dac_code, float LTC2605_lsb, int16_t LTC2605_offset)
Calculate the LTC2605 DAC output voltage given the DAC code, offset, and LSB value.
Definition: LTC2605.cpp:98
static uint16_t get_code()
Get code to send to DAC directly, in decimal, hex, or binary.
Definition: DC935A.ino:310
#define REF_INTERNAL
Stored reference state is Internal.
Definition: DC935A.ino:104
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.
Definition: DC935A.ino:259
static void print_prompt(int16_t selected_dac)
Prints main menu.
Definition: DC935A.ino:341
static uint8_t reference_mode
Tells whether to set internal or external reference.
Definition: DC935A.ino:124
void quikeval_I2C_init(void)
Initializes Linduino I2C port.
Definition: LT_I2C.cpp:394
static int8_t menu_1_select_dac(int16_t *selected_dac)
Select which DAC to operate on.
Definition: DC935A.ino:206
void quikeval_I2C_connect(void)
Switch MUX to connect I2C pins to QuikEval connector.
Definition: LT_I2C.cpp:401
static int16_t prompt_voltage_or_code()
Prompt user to enter a voltage or digital code to send to DAC.
Definition: DC935A.ino:280
LTC2605: Octal 16-/14-/12-Bit Rail-to Rail DACs in 16-Lead SSOP.