| Linduino 1.3.0 Linear Technology Arduino-Compatible Demonstration Board

LTC2380_24.cpp
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1 /*!
2 LTC2380-24: Low Noise, High Speed, 24-Bit SAR ADC With Digital Filter
3
4 @verbatim
5
6
7 @endverbatim
8
9 http://www.linear.com/product/LTC2380-24
10
11
12 Copyright 2018(c) Analog Devices, Inc.
13
14 All rights reserved.
15
16 Redistribution and use in source and binary forms, with or without
17 modification, are permitted provided that the following conditions are met:
18 - Redistributions of source code must retain the above copyright
19 notice, this list of conditions and the following disclaimer.
20 - Redistributions in binary form must reproduce the above copyright
21 notice, this list of conditions and the following disclaimer in
22 the documentation and/or other materials provided with the
23 distribution.
24 - Neither the name of Analog Devices, Inc. nor the names of its
25 contributors may be used to endorse or promote products derived
26 from this software without specific prior written permission.
27 - The use of this software may or may not infringe the patent rights
28 of one or more patent holders. This license does not release you
29 from the requirement that you obtain separate licenses from these
30 patent holders to use this software.
31 - Use of the software either in source or binary form, must be run
32 on or directly connected to an Analog Devices Inc. component.
33
34 THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
35 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
36 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
37 IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
38 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
39 LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
40 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
41 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
42 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
43 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44 */
45
46 //! @ingroup Analog_to_Digital_Converters
47 //! @{
48 //! @defgroup LTC2380-24 LTC2380-24: Low Noise, High Speed, 24-Bit SAR ADC With Digital Filter
49 //! @}
50
51 /*! @file
52 @ingroup LTC2380-24
53 Library for LTC2380-24: Low Noise, High Speed, 24-Bit SAR ADC With Digital Filter
54 */
55
56 #include <Arduino.h>
57 #include <stdint.h>
58 #include "Linduino.h"
59 #include "LT_SPI.h"
60 #include "LTC2380_24.h"
61 #include <SPI.h>
62 #include "UserInterface.h"
63
64 // Reads from a SPI LTC2380-XX device that has no configuration word and a 32 bit output word in 2's complement format.
65 void LTC2380_read(int32_t *ptr_adc_code, int16_t *ptr_cycles)
66 {
67 int N;
68 int negative;
69
70 Serial.print("\nEnter the number of CNV pulses: ");
71 while (Serial.available());
72 N = read_int();
73 while (N--) // PB2 (CS) pin is connected to CNV pin.
74 {
75 PORTB |= B00000100; // Pull CNV pin high
76 __asm__("nop\n\t");
77 PORTB &= B11111011; // Pull CNV pin low
78 __asm__("nop\n\t");
79 }
80
81 LT_union_int16_2bytes cycles; // LTC2380 data and command
82 cycles.LT_uint16 = 0; // Set to zero, not necessary but avoids random data in scope shots.
83
84 // Form a four byte object to hold four bytes of data
85 LT_union_int32_4bytes data; //instantiate the union
86 data.LT_byte[3] = 0;
87 data.LT_byte[2] = 0;
88 data.LT_byte[1] = 0;
89 data.LT_byte[0] = 0;
90
91 data.LT_byte[2] = spi_read(0);
92 data.LT_byte[1] = spi_read(0);
93 data.LT_byte[0] = spi_read(0);
94 cycles.LT_byte[1] = spi_read(0);
95 cycles.LT_byte[0] = spi_read(0);
96
97 negative = (data.LT_byte[2] & 0x80) != 0;
98 if (negative)
99 {
100 data.LT_byte[3] = 0xFF;
101 }
102 *ptr_adc_code = data.LT_int32;
103 *ptr_cycles = cycles.LT_int16;
104
105 return;
106 }
107
108 // Calculates the voltage corresponding to an adc code in 2's complement, given the reference voltage (in volts)
109 float LTC2380_code_to_voltage(int32_t adc_code, uint8_t gain_compression, float vref)
110 {
111 float voltage;
112
113 if (gain_compression == 1)
114 vref = 0.8*vref;
115
116 voltage = (float)adc_code;
117 voltage = voltage / (pow(2,24)-1); //! 2) This calculates the input as a fraction of the reference voltage (dimensionless)
118 voltage = voltage * vref; //! 3) Multiply fraction by Vref to get the actual voltage at the input (in volts)
119
120 return(voltage);
121 }
LT_union_int32_4bytes::LT_byte
uint8_t LT_byte[4]
4 bytes (unsigned 8-bit integers) to be converted to a 32-bit signed or unsigned integer ...
Definition: Linduino.h:112
Linduino.h
Header File for Linduino Libraries and Demo Code.
data
union LT_union_int32_4bytes data
Definition: DC2094A.ino:138
LTC2380_24.h
LTC2380-24: Low Noise, High Speed, 24-Bit SAR ADC With Digital Filter.
LT_union_int16_2bytes::LT_int16
int16_t LT_int16
16-bit signed integer to be converted to two bytes
Definition: Linduino.h:101
LT_union_int16_2bytes::LT_uint16
uint16_t LT_uint16
16-bit unsigned integer to be converted to two bytes
Definition: Linduino.h:102
LT_union_int32_4bytes::LT_int32
int32_t LT_int32
32-bit signed integer to be converted to four bytes
Definition: Linduino.h:110
LT_SPI.h
LT_SPI: Routines to communicate with ATmega328P&#39;s hardware SPI port.
UserInterface.h
read_int
int32_t read_int()
Definition: UserInterface.cpp:93
spi_read
int8_t spi_read(int8_t data)
The data byte to be written.
Definition: LT_SPI.cpp:189
LT_union_int32_4bytes
This union splits one int32_t (32-bit signed integer) or uint32_t (32-bit unsigned integer) four uint...
Definition: Linduino.h:108
LT_union_int16_2bytes
This union splits one int16_t (16-bit signed integer) or uint16_t (16-bit unsigned integer) into two ...
Definition: Linduino.h:99
voltage
static float voltage
Definition: DC2289AA.ino:71
vref
float vref
Definition: LTC2492_Thermocouple_Meter.ino:129
LT_union_int16_2bytes::LT_byte
uint8_t LT_byte[2]
2 bytes (unsigned 8-bit integers) to be converted to a 16-bit signed or unsigned integer ...
Definition: Linduino.h:103
LTC2380_code_to_voltage
float LTC2380_code_to_voltage(int32_t adc_code, uint8_t gain_compression, float vref)
Calculates the LTC2380 input voltage given the binary data and lsb weight.
Definition: LTC2380_24.cpp:109
LTC2380_read
void LTC2380_read(int32_t *ptr_adc_code, int16_t *ptr_cycles)
Reads the LTC2380 and returns 32-bit data in 2&#39;s complement format.
Definition: LTC2380_24.cpp:65
adc_code
static uint32_t adc_code
Definition: DC2071AA.ino:113