1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
#ifndef vishnuADC
#define vishnuADC
#include "Arduino.h"
#include <SPI.h>
/**
* Union representing the "config register" in 3 ways:
* bits, word (16 bits) and nibbles (4 bits)
* (See the datasheet [1] for more information)
*/
///Union configuration register
union Config {
///Structure of the config register of the ADS1118. (See datasheet [1])
struct {
uint8_t reserved:1; ///< "Reserved" bit
uint8_t noOperation:2; ///< "NOP" bits
uint8_t pullUp:1; ///< "PULL_UP_EN" bit
uint8_t sensorMode:1; ///< "TS_MODE" bit
uint8_t rate:3; ///< "DR" bits
uint8_t operatingMode:1;///< "MODE" bit
uint8_t pga:3; ///< "PGA" bits
uint8_t mux:3; ///< "MUX" bits
uint8_t singleStart:1; ///< "SS" bit
} bits;
uint16_t word; ///< Representation in word (16-bits) format
struct {
uint8_t lsb; ///< Byte LSB
uint8_t msb; ///< Byte MSB
} byte; ///< Representation in bytes (8-bits) format
};
/**
* Class representing the ADS1118 sensor chip
* @author Alvaro Salazar <alvaro@denkitronik.com>
*/
class ADS1118 {
public:
ADS1118(uint8_t io_pin_cs); ///< Constructor
void begin(); ///< This method initialize the SPI port and the config register
double getTemperature(); ///< Getting the temperature in degrees celsius from the internal sensor of the ADS1118
uint16_t getADCValue(uint8_t inputs);///< Getting a sample from the specified input
double getMilliVolts(uint8_t inputs);//< Getting the millivolts from the specified inputs
double getMilliVolts(); ///< Getting the millivolts from the settled inputs
void decodeConfigRegister(union Config configRegister); ///< Decoding a configRegister structure and then print it out to the Serial port
void setSamplingRate(uint8_t samplingRate);///< Setting the sampling rate specified in the config register
void setFullScaleRange(uint8_t fsr);///< Setting the full scale range in the config register
void setContinuousMode(); ///< Setting to continuous adquisition mode
void setSingleShotMode(); ///< Setting to single shot adquisition and power down mode
void disablePullup(); ///< Disabling the internal pull-up resistor of the DOUT pin
void enablePullup(); ///< Enabling the internal pull-up resistor of the DOUT pin
void setInputSelected(uint8_t input);///< Setting the inputs to be adquired in the config register.
//Input multiplexer configuration selection for bits "MUX"
//Differential inputs
const uint8_t DIFF_0_1 = 0b000; ///< Differential input: Vin=A0-A1
const uint8_t DIFF_0_3 = 0b001; ///< Differential input: Vin=A0-A3
const uint8_t DIFF_1_3 = 0b010; ///< Differential input: Vin=A1-A3
const uint8_t DIFF_2_3 = 0b011; ///< Differential input: Vin=A2-A3
//Single ended inputs
const uint8_t AIN_0 = 0b100; ///< Single ended input: Vin=A0
const uint8_t AIN_1 = 0b101; ///< Single ended input: Vin=A1
const uint8_t AIN_2 = 0b110; ///< Single ended input: Vin=A2
const uint8_t AIN_3 = 0b111; ///< Single ended input: Vin=A3
union Config configRegister; ///< Config register
//Bit constants
const long int SCLK = 4000000;///< ADS1118 SCLK frequency: 4000000 Hz Maximum for ADS1018 (4Mhz)
// Used by "SS" bit
const uint8_t START_NOW = 1; ///< Start of conversion in single-shot mode
// Used by "TS_MODE" bit
const uint8_t ADC_MODE = 0; ///< External (inputs) voltage reading mode
const uint8_t TEMP_MODE = 1; ///< Internal temperature sensor reading mode
// Used by "MODE" bit
const uint8_t CONTINUOUS = 0; ///< Continuous conversion mode
const uint8_t SINGLE_SHOT = 1; ///< Single-shot conversion and power down mode
// Used by "PULL_UP_EN" bit
const uint8_t PULLUP = 1; ///< Internal pull-up resistor enabled for DOUT ***DEFAULT
const uint8_t NO_PULLUP = 0; ///< Internal pull-up resistor disabled
// Used by "NOP" bits
const uint8_t VALID_CFG = 0b01; ///< Data will be written to Config register
const uint8_t NO_VALID_CFG= 0b00; ///< Data won't be written to Config register
// Used by "Reserved" bit
const uint8_t RESERVED = 1; ///< Its value is always 1, reserved
/*Full scale range (FSR) selection by "PGA" bits.
[Warning: this could increase the noise and the effective number of bits (ENOB). See tables above]*/
const uint8_t FSR_6144 = 0b000; ///< Range: ±6.144 v. LSB SIZE = 187.5μV
const uint8_t FSR_4096 = 0b001; ///< Range: ±4.096 v. LSB SIZE = 125μV
const uint8_t FSR_2048 = 0b010; ///< Range: ±2.048 v. LSB SIZE = 62.5μV ***DEFAULT
const uint8_t FSR_1024 = 0b011; ///< Range: ±1.024 v. LSB SIZE = 31.25μV
const uint8_t FSR_0512 = 0b100; ///< Range: ±0.512 v. LSB SIZE = 15.625μV
const uint8_t FSR_0256 = 0b111; ///< Range: ±0.256 v. LSB SIZE = 7.8125μV
/*Sampling rate selection by "DR" bits.
[Warning: this could increase the noise and the effective number of bits (ENOB). See tables above]*/
const uint8_t RATE_8SPS = 0b000; ///< 8 samples/s, Tconv=125ms
const uint8_t RATE_16SPS = 0b001; ///< 16 samples/s, Tconv=62.5ms
const uint8_t RATE_32SPS = 0b010; ///< 32 samples/s, Tconv=31.25ms
const uint8_t RATE_64SPS = 0b011; ///< 64 samples/s, Tconv=15.625ms
const uint8_t RATE_128SPS = 0b100; ///< 128 samples/s, Tconv=7.8125ms
const uint8_t RATE_250SPS = 0b101; ///< 250 samples/s, Tconv=4ms
const uint8_t RATE_475SPS = 0b110; ///< 475 samples/s, Tconv=2.105ms
const uint8_t RATE_860SPS = 0b111; ///< 860 samples/s, Tconv=1.163ms
// const uint8_t RATE_3300SPS = 0b110; ///< 860 samples/s, Tconv=1.163ms
private:
uint8_t lastSensorMode=3; ///< Last sensor mode selected (ADC_MODE or TEMP_MODE or none)
uint8_t cs; ///< Chip select pin (choose one)
const float pgaFSR[8] = {6.144, 4.096, 2.048, 1.024, 0.512, 0.256, 0.256, 0.256};
const uint8_t CONV_TIME[8]={125, 63, 32, 16, 8, 4, 3, 2}; ///< Array containing the conversions time in ms
};
#endif
|
