| Linduino 1.3.0 Linear Technology Arduino-Compatible Demonstration Board

LTC2442_Datalogger.ino
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1 /*!
2 LTC2442: 24-Bit High Speed 4-Channel Delta Sigma ADCs with Integrated Amplifier
3
4 @verbatim
5
6 The LTC2442 is a 4-channel (2-differential) high speed 24-bit No Latency Delta Sigma ADCs.
7 They use a proprietary delta-sigma architecture enabling variable speed/resolution. Through
8 a simple 4-wire serial interface, ten speed/resolution combinations 6.9Hz/280nVRMS to
9 3.5kHz/25uVRMS (4kHz with external oscillator) can be selected with no latency between
10 conversion results or shift in DC accuracy (offset, full-scale, linearity, drift).
11 Additionally, a 2X speed mode can be selected enabling output rates up to 7kHz (8kHz if an
12 external oscillator is used) with one cycle latency.
13
14 @endverbatim
15
16 http://www.linear.com/product/LTC2442
17
18 http://www.linear.com/product/LTC2442#demoboards
19
20
21 Copyright 2018(c) Analog Devices, Inc.
22
23 All rights reserved.
24
25 Redistribution and use in source and binary forms, with or without
26 modification, are permitted provided that the following conditions are met:
27 - Redistributions of source code must retain the above copyright
28 notice, this list of conditions and the following disclaimer.
29 - Redistributions in binary form must reproduce the above copyright
30 notice, this list of conditions and the following disclaimer in
31 the documentation and/or other materials provided with the
32 distribution.
33 - Neither the name of Analog Devices, Inc. nor the names of its
34 contributors may be used to endorse or promote products derived
35 from this software without specific prior written permission.
36 - The use of this software may or may not infringe the patent rights
37 of one or more patent holders. This license does not release you
38 from the requirement that you obtain separate licenses from these
39 patent holders to use this software.
40 - Use of the software either in source or binary form, must be run
41 on or directly connected to an Analog Devices Inc. component.
42
43 THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
44 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
45 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
46 IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
47 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
48 LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
49 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
50 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
51 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
52 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
53 */
54
55 #include <stdint.h>
56 #include <Arduino.h>
57 #include "Linduino.h"
58 #include "QuikEval_EEPROM.h"
59 #include "UserInterface.h"
60 #include <SPI.h>
61 #include "LT_SPI.h"
62 #include <Wire.h>
63 #include "LT_I2C.h"
64 #include "LTC24XX_general.h"
65
66 #define CS QUIKEVAL_CS //!< The chip select
67
68 ///////////////////////////////////////////////////////////////
69 // Begin program behavior setup ///////////////////////////////
70 ///////////////////////////////////////////////////////////////
71
72 // Lookup tables of channels to scan.
73 // UN-comment one section below: First section is odd channels as negative input
74 // Second section is even channels as negative input.
75 // Third section is single-ended channels with respec to COM.
76
77 const uint8_t CHANNEL_ARRAY[2] = {LTC24XX_MULTI_CH_P0_N1, LTC24XX_MULTI_CH_P2_N3}; //!< Build the command for differential mode
78
79 //const uint8_t CHANNEL_ARRAY[2] = {LTC24XX_MULTI_CH_P1_N0, LTC24XX_MULTI_CH_P3_N2}; //!< Build the command for differential mode
80
81 //const uint8_t CHANNEL_ARRAY[4] = {LTC24XX_MULTI_CH_CH0, LTC24XX_MULTI_CH_CH1, LTC24XX_MULTI_CH_CH2, LTC24XX_MULTI_CH_CH3}; //!< Builds the command for single-ended mode
82
83
84 //UN-comment one line below to set the OSR mode:
85 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_32768;
86 const uint8_t OSR = LTC24XX_MULTI_CH_OSR_16384;
87 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_8192;
88 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_4096;
89 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_2048;
90 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_1024;
91 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_512;
92 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_256;
93 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_128;
94 //const uint8_t OSR = LTC24XX_MULTI_CH_OSR_64;
95
96 float LTC2442_vref = 5.0; // Reference voltage
97 uint16_t EOC_timout = 250; // End of conversion timeout (must be larger than tconv(max))
98 uint16_t loop_delay = 0; // the delay between loops
99 uint16_t channel_read_delay = 0; // The delay between channel readings
100
101 // Display format. UN-comment one line below.
102 #define FLOATING
103 //#define RAW
104
105 // UN-comment to prime the ADC before taking data for a given scan, purging stale data from previous scan.
106 // May be useful for single scans with a long delay between scans.
107 //#define PRIME_BEFORE_SCAN
108
109 ///////////////////////////////////////////////////////////////
110 // End program behavior setup ///////////////////////////////
111 ///////////////////////////////////////////////////////////////
112
113
114 uint8_t array_size = sizeof(CHANNEL_ARRAY); // Get size of array (in bytes, each element is a byte)
115
116 // Prototypes
117 void read_LTC2442(float vref, uint16_t eoc_timeout, uint16_t channel_delay);
118 void print_raw(int32_t *rawresults);
119 void print_all(float *results);
120 void print_prompt();
121
122
123 //! Initialize Linduino
124 void setup()
125 {
126 char demo_name[] = "DC979"; // Demo Board Name stored in QuikEval EEPROM
127 int8_t demo_board_connected; // Set to 1 if the board is connected
128
129 Serial.begin(115200); // Initialize the serial port to the PC
130 Serial.println(F("Welcome to the LTC2442 Test Program\n"));
131 delay(200);
132
133 quikeval_I2C_init(); // Enable the I2C port
134 quikeval_SPI_init(); // Configure the spi port for 4volts SCK
135 quikeval_SPI_connect(); // Connect SPI to main data port
136
137 demo_board_connected = discover_demo_board(demo_name);
138
139 // If demo board is not connected loop forever
140 if (!demo_board_connected)
141 Serial.println(F("Standard demo board not detected, verify hardware connections to your circuit."));
142
143 print_prompt(); // Prints the prompt
144 } // End of setup()
145
146
147 //! Repeats Linduino loop
148 void loop()
149 {
150 static char user_command; // The user input command
151 user_command = read_char(); // Reads the users input
152 // Serial.println(user_command); // Displays the user input
153
154 switch (user_command)
155 {
156 case 'S':
157 case 's':
158 // Single loop
159 read_LTC2442(LTC2442_vref, EOC_timout, channel_read_delay); // Read all the channels
160 break;
161 case 'C':
162 case 'c':
163 // Continous loop
164 do
165 {
166 read_LTC2442(LTC2442_vref, EOC_timout, channel_read_delay); // Read all the channels
167 delay(loop_delay); // Delay before repeating the loop
168 }
169 while (Serial.available() == false); // Check to see is anything was entered
170 read_int(); // Clears the Serial.available
171 break;
172 default:
173 Serial.println(F("Incorrect Option"));
174 break;
175 }
176 }
177
178 //! Print the Prompt
179 void print_prompt()
180 {
181 Serial.println();
182 Serial.println(F("S-Single Loop"));
183 Serial.println(F("C-Continuous Loop"));
184 Serial.println(F(" Enter any character to exit Continuous Loop"));
185
186 Serial.print(F("Enter a command: "));
187 }
188
189 //! Reads the LTC2442 and displays the results
190 void read_LTC2442(float vref, uint16_t eoc_timeout, uint16_t channel_delay)
191 {
192 float floatresults[16];
193 int32_t rawresults[16];
194 int32_t adc_code = 0;
195 uint8_t i;
196
197 #ifdef PRIME_BEFORE_SCAN // If defined, prime first channel so that data is "less stale"
198 LTC24XX_EOC_timeout(CS, eoc_timeout); // Wait for end of conversion
199 LTC24XX_SPI_16bit_command_32bit_data(CS, CHANNEL_ARRAY[0], OSR, &adc_code); // Prime with first channel
200 #endif
201
202 for (i=0; i<array_size; i++)
203 {
204 delay(channel_delay);
205 LTC24XX_EOC_timeout(CS, eoc_timeout); // Wait for end of conversion
206 LTC24XX_SPI_16bit_command_32bit_data(CS, CHANNEL_ARRAY[(i+1)%array_size], OSR, &adc_code); // Read the ADC
207 rawresults[i%array_size] = adc_code;
208 floatresults[i%array_size] = LTC24XX_diff_code_to_voltage(adc_code, vref); // Convert ADC code to voltage
209 }
210 #ifdef FLOATING
211 print_all(floatresults); // Display results
212 #else
213 print_raw(rawresults);
214 #endif
215 }
216
217 //! Displays the the data in the array
218 void print_all(float *floatresults)
219 {
220 uint8_t i;
221 for (i=0; i<array_size; i++)
222 {
223 Serial.print(floatresults[i], 8);
224 if (!((i+1)%array_size)) Serial.println();
225 else Serial.print(F(" , "));
226 }
227 }
228
229 void print_raw(int32_t *rawresults)
230 {
231 uint8_t i;
232 for (i=0; i<array_size; i++)
233 {
234 Serial.print(rawresults[i]);
235 if (!((i+1)%array_size)) Serial.println();
236 else Serial.print(F(" , "));
237 }
238 }
print_prompt
static void print_prompt()
Print the Prompt.
Definition: LTC2442_Datalogger.ino:179
user_command
unsigned char user_command
Definition: Serial_EEPROM_Test.ino:75
array_size
static uint8_t array_size
Definition: LTC2442_Datalogger.ino:114
CHANNEL_ARRAY
const uint8_t CHANNEL_ARRAY[2]
Build the command for differential mode.
Definition: LTC2442_Datalogger.ino:77
loop_delay
static uint16_t loop_delay
Definition: LTC2442_Datalogger.ino:98
Linduino.h
Header File for Linduino Libraries and Demo Code.
setup
static void setup()
Initialize Linduino.
Definition: LTC2442_Datalogger.ino:124
LTC24XX_EOC_timeout
int8_t LTC24XX_EOC_timeout(uint8_t cs, uint16_t miso_timeout)
Checks for EOC with a specified timeout.
Definition: LTC24XX_general.cpp:82
print_all
static void print_all(float *results)
Displays the the data in the array.
Definition: LTC2442_Datalogger.ino:218
LTC24XX_general.h
LTC24XX General Library: Functions and defines for all SINC4 Delta Sigma ADCs.
LTC24XX_SPI_16bit_command_32bit_data
void LTC24XX_SPI_16bit_command_32bit_data(uint8_t cs, uint8_t adc_command_high, uint8_t adc_command_low, int32_t *adc_code)
Reads from LTC24XX ADC that accepts a 16 bit configuration and returns a 32 bit result.
Definition: LTC24XX_general.cpp:136
eoc_timeout
static uint16_t eoc_timeout
timeout in ms
Definition: LTC2492_Panel_Meter.ino:135
QuikEval_EEPROM.h
QuikEval EEPROM Library.
LTC24XX_MULTI_CH_P2_N3
#define LTC24XX_MULTI_CH_P2_N3
Definition: LTC24XX_general.h:209
print_raw
static void print_raw(int32_t *rawresults)
Definition: LTC2442_Datalogger.ino:229
LTC24XX_MULTI_CH_OSR_16384
#define LTC24XX_MULTI_CH_OSR_16384
Definition: LTC24XX_general.h:250
quikeval_SPI_init
void quikeval_SPI_init(void)
Configure the SPI port for 4Mhz SCK.
Definition: LT_SPI.cpp:151
discover_demo_board
int8_t discover_demo_board(char *demo_name)
Read the ID string from the EEPROM and determine if the correct board is connected.
Definition: QuikEval_EEPROM.cpp:141
LT_SPI.h
LT_SPI: Routines to communicate with ATmega328P&#39;s hardware SPI port.
OSR
const uint8_t OSR
Definition: LTC2442_Datalogger.ino:86
LT_I2C.h
LT_I2C: Routines to communicate with ATmega328P&#39;s hardware I2C port.
CS
#define CS
LTC2442: 24-Bit High Speed 4-Channel Delta Sigma ADCs with Integrated Amplifier.
Definition: LTC2442_Datalogger.ino:66
LTC24XX_diff_code_to_voltage
float LTC24XX_diff_code_to_voltage(int32_t adc_code, float vref)
Calculates the voltage corresponding to an ADC code, given the reference voltage. ...
Definition: LTC24XX_general.cpp:389
demo_name
char demo_name[]
Demo Board Name stored in QuikEval EEPROM.
Definition: DC1880A.ino:97
LTC2442_vref
static float LTC2442_vref
Definition: LTC2442_Datalogger.ino:96
quikeval_SPI_connect
void quikeval_SPI_connect()
Connect SPI pins to QuikEval connector through the Linduino MUX. This will disconnect I2C...
Definition: LT_SPI.cpp:138
UserInterface.h
read_int
int32_t read_int()
Definition: UserInterface.cpp:93
EOC_timout
static uint16_t EOC_timout
Definition: LTC2442_Datalogger.ino:97
quikeval_I2C_init
void quikeval_I2C_init(void)
Initializes Linduino I2C port.
Definition: LT_I2C.cpp:394
i
static int i
Definition: DC2430A.ino:184
vref
float vref
Definition: LTC2492_Thermocouple_Meter.ino:129
LTC24XX_MULTI_CH_P0_N1
#define LTC24XX_MULTI_CH_P0_N1
Definition: LTC24XX_general.h:206
read_LTC2442
static void read_LTC2442(float vref, uint16_t eoc_timeout, uint16_t channel_delay)
Reads the LTC2442 and displays the results.
Definition: LTC2442_Datalogger.ino:190
channel_read_delay
static uint16_t channel_read_delay
Definition: LTC2442_Datalogger.ino:99
read_char
int8_t read_char()
Definition: UserInterface.cpp:116
adc_code
static uint32_t adc_code
Definition: DC2071AA.ino:113
loop
static void loop()
Repeats Linduino loop.
Definition: LTC2442_Datalogger.ino:148
demo_board_connected
static uint8_t demo_board_connected
Set to 1 if the board is connected.
Definition: _24xx_iso_spi_delay.ino:71