Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board
LTC2991.cpp
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1 /*!
2 LTC2991: 14-bit Octal I2C Voltage, Current, and Temperature Monitor
3 
4 @verbatim
5 
6 The LTC2991 is used to monitor system temperatures, voltages and currents.
7 Through the I2C serial interface, the eight monitors can individually measure
8 supply voltages and can be paired for differential measurements of current sense
9 resistors or temperature sensing transistors. Additional measurements include
10 internal temperature and internal VCC. The internal 10ppm reference minimizes
11 the number of supporting components and area required. Selectable address and
12 configurable functionality give the LTC2991 flexibility to be incorporated in
13 various systems needing temperature, voltage or current data. The LTC2991 fits
14 well in systems needing submillivolt voltage resolution, 1% current measurement
15 and 1 degree Celsius temperature accuracy or any combination of the three.
16 
17 @endverbatim
18 
19 http://www.linear.com/product/LTC2991
20 
21 http://www.linear.com/product/LTC2991#demoboards
22 
23 
24 Copyright 2018(c) Analog Devices, Inc.
25 
26 All rights reserved.
27 
28 Redistribution and use in source and binary forms, with or without
29 modification, are permitted provided that the following conditions are met:
30  - Redistributions of source code must retain the above copyright
31  notice, this list of conditions and the following disclaimer.
32  - Redistributions in binary form must reproduce the above copyright
33  notice, this list of conditions and the following disclaimer in
34  the documentation and/or other materials provided with the
35  distribution.
36  - Neither the name of Analog Devices, Inc. nor the names of its
37  contributors may be used to endorse or promote products derived
38  from this software without specific prior written permission.
39  - The use of this software may or may not infringe the patent rights
40  of one or more patent holders. This license does not release you
41  from the requirement that you obtain separate licenses from these
42  patent holders to use this software.
43  - Use of the software either in source or binary form, must be run
44  on or directly connected to an Analog Devices Inc. component.
45 
46 THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
47 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
48 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
49 IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
50 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
51 LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
52 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
53 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
54 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
55 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56 */
57 
58 //! @ingroup Power_Monitors
59 //! @{
60 //! @defgroup LTC2991 LTC2991: 14-bit Octal I2C Voltage, Current, and Temperature Monitor
61 //! @}
62 
63 /*! @file
64  @ingroup LTC2991
65  Library for LTC2991: 14-bit Octal I2C Voltage, Current, and Temperature Monitor
66 */
67 
68 #include <Arduino.h>
69 #include <stdint.h>
70 #include "Linduino.h"
71 #include "LT_I2C.h"
72 #include "LTC2991.h"
73 #include <Wire.h>
74 
75 // Reads a 14-bit adc_code from LTC2991.
76 int8_t LTC2991_adc_read(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid)
77 {
78  int8_t ack = 0;
79  uint16_t code;
80  ack = i2c_read_word_data(i2c_address, msb_register_address, &code);
81 
82  *data_valid = (code >> 15) & 0x01; // Place Data Valid Bit in *data_valid
83 
84  *adc_code = code & 0x7FFF; // Removes data valid bit to return proper adc_code value
85 
86  return(ack);
87 }
88 
89 // Reads a 14-bit adc_code from the LTC2991 but enforces a maximum timeout.
90 // Similar to LTC2991_adc_read except it repeats until the data_valid bit is set, it fails to receive an I2C acknowledge, or the timeout (in milliseconds)
91 // expires. It keeps trying to read from the LTC2991 every millisecond until the data_valid bit is set (indicating new data since the previous
92 // time this register was read) or until it fails to receive an I2C acknowledge (indicating an error on the I2C bus).
93 int8_t LTC2991_adc_read_timeout(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid, uint16_t timeout, uint8_t status_bit)
94 {
95  int8_t ack = 0;
96  uint8_t reg_data;
97  uint16_t timer_count; // Timer count for data_valid
98 
99  for (timer_count = 0; timer_count < timeout; timer_count++)
100  {
101 
102  if (status_bit<8)
103  {
104  ack |= LTC2991_register_read(i2c_address, LTC2991_STATUS_LOW_REG, &reg_data); //! 1)Read status register until correct data valid bit is set
105  }
106  else
107  {
108  ack |= LTC2991_register_read(i2c_address, LTC2991_STATUS_HIGH_REG, &reg_data); //! 1)Read status register until correct data valid bit is set
109  if (status_bit==8)
110  {
111  status_bit =1;
112  }
113  else
114  {
115  status_bit = 0;
116  }
117  }
118 
119  if ((ack) || (((reg_data>>status_bit)&0x1)==1))
120  {
121  break;
122  }
123 
124  delay(1);
125  }
126 
127  ack |= LTC2991_adc_read(i2c_address, msb_register_address, &(*adc_code), &(*data_valid)); //! 2) It's either valid or it's timed out, we read anyways
128  if (*data_valid !=1)
129  {
130  Serial.println("Data not valid");
131  Serial.println(*data_valid);
132  return (1);
133  }
134  return(ack);
135 }
136 
137 // Reads new data (even after a mode change) by flushing old data and waiting for the data_valid bit to be set.
138 // This function simplifies adc reads when modes are changing. For example, if V1-V2 changes from temperature mode
139 // to differential voltage mode, the data in the register may still correspond to the temperature reading immediately
140 // after the mode change. Flushing one reading and waiting for a new reading guarantees fresh data is received.
141 // If the timeout is reached without valid data (*data_valid=1) the function exits.
142 int8_t LTC2991_adc_read_new_data(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid, uint16_t timeout)
143 {
144  int8_t ack = 0;
145 
146  ack |= LTC2991_adc_read_timeout(i2c_address, msb_register_address, &(*adc_code), &(*data_valid), timeout, ((msb_register_address/2) - 0x05)); //! 1) Throw away old data
147  ack |= LTC2991_adc_read_timeout(i2c_address, msb_register_address, &(*adc_code), &(*data_valid), timeout, ((msb_register_address/2) - 0x05)); //! 2) Read new data
148 
149  return(ack);
150 }
151 
152 // Reads an 8-bit register from the LTC2991 using the standard repeated start format.
153 int8_t LTC2991_register_read(uint8_t i2c_address, uint8_t register_address, uint8_t *register_data)
154 {
155  int8_t ack = 0;
156 
157  ack = i2c_read_byte_data(i2c_address, register_address, register_data);
158  return(ack);
159 }
160 
161 // Write one byte to an LTC2991 register.
162 // Writes to an 8-bit register inside the LTC2991 using the standard I2C repeated start format.
163 int8_t LTC2991_register_write(uint8_t i2c_address, uint8_t register_address, uint8_t register_data)
164 {
165  int8_t ack = 0;
166 
167  ack = i2c_write_byte_data(i2c_address, register_address, register_data);
168  return(ack);
169 }
170 
171 // Used to set and clear bits in a control register. bits_to_set will be bitwise OR'd with the register.
172 // bits_to_clear will be inverted and bitwise AND'd with the register so that every location with a 1 will result in a 0 in the register.
173 int8_t LTC2991_register_set_clear_bits(uint8_t i2c_address, uint8_t register_address, uint8_t bits_to_set, uint8_t bits_to_clear)
174 {
175  uint8_t register_data;
176  int8_t ack = 0;
177 
178  ack |= LTC2991_register_read(i2c_address, register_address, &register_data); //! 1) Read register
179  register_data = register_data & (~bits_to_clear); //! 2) Clear bits that were set to be cleared
180  register_data = register_data | bits_to_set;
181  ack |= LTC2991_register_write(i2c_address, register_address, register_data); //! 3) Write to register with the cleared bits
182  return(ack);
183 }
184 
185 // Calculates the LTC2991 single-ended input voltages
186 float LTC2991_code_to_single_ended_voltage(int16_t adc_code, float LTC2991_single_ended_lsb)
187 {
188  float voltage;
189  int16_t sign = 1;
190  if (adc_code >> 14)
191  {
192  adc_code = (adc_code ^ 0x7FFF) + 1; //! 1) Converts two's complement to binary
193  sign = -1;
194  }
195  adc_code = (adc_code & 0x3FFF);
196  voltage = ((float) adc_code) * LTC2991_single_ended_lsb * sign; //! 2) Convert code to voltage from lsb
197  return (voltage);
198 }
199 
200 // Calculates the LTC2991 Vcc voltage
201 float LTC2991_code_to_vcc_voltage(int16_t adc_code, float LTC2991_single_ended_lsb)
202 {
203  float voltage;
204  int16_t sign = 1;
205  if (adc_code >> 14)
206  {
207  adc_code = (adc_code ^ 0x7FFF) + 1; //! 1) Converts two's complement to binary
208  sign = -1;
209  }
210 
211  voltage = (((float) adc_code) * LTC2991_single_ended_lsb * sign) + 2.5; //! 2) Convert code to Vcc Voltage from single-ended lsb
212  return (voltage);
213 }
214 
215 // Calculates the LTC2991 differential input voltage.
216 float LTC2991_code_to_differential_voltage(int16_t adc_code, float LTC2991_differential_lsb)
217 {
218  float voltage;
219  int16_t sign = 1;
220  if (adc_code >> 14)
221  {
222  adc_code = (adc_code ^ 0x7FFF) + 1; //! 1)Converts two's complement to binary
223  sign = -1;
224  }
225  voltage = ((float) adc_code) * LTC2991_differential_lsb * sign; //! 2) Convert code to voltage form differential lsb
226  return (voltage);
227 }
228 
229 // Calculates the LTC2991 temperature
230 float LTC2991_temperature(int16_t adc_code, float LTC2991_temperature_lsb, boolean unit)
231 {
232  float temperature;
233  adc_code = (adc_code & 0x1FFF); //! 1) Removes first 3 bits
234  if (!unit) //! 2)Checks to see if it's Kelvin
235  {
236  if (adc_code >>12)
237  {
238  adc_code = (adc_code | 0xE000); //! Sign extend if it's not Kelvin (Celsius)
239  }
240  }
241  temperature = ((float) adc_code) * LTC2991_temperature_lsb; //! 3) Converts code to temperature from temperature lsb
242 
243  return (temperature);
244 }
245 
246 // Calculates the LTC2991 diode voltage
247 float LTC2991_code_to_diode_voltage(int16_t adc_code, float LTC2991_diode_voltage_lsb)
248 {
249  float voltage;
250  adc_code = (adc_code & 0x1FFF); //! 1) Removes first 3 bits
251  voltage = ((float) adc_code) * LTC2991_diode_voltage_lsb; //! 2) Convert code to voltage from diode voltage lsb
252  return (voltage);
253 }
uint8_t i2c_address
int8_t LTC2991_register_set_clear_bits(uint8_t i2c_address, uint8_t register_address, uint8_t bits_to_set, uint8_t bits_to_clear)
Used to set and clear bits in a control register.
Definition: LTC2991.cpp:173
int8_t i2c_read_byte_data(uint8_t address, uint8_t command, uint8_t *value)
Read a byte of data at register specified by "command", store in "value".
Definition: LT_I2C.cpp:124
int8_t LTC2991_adc_read_timeout(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid, uint16_t timeout, uint8_t status_bit)
Reads a 14-bit adc_code from the LTC2991 but enforces a maximum timeout.
Definition: LTC2991.cpp:93
float LTC2991_code_to_vcc_voltage(int16_t adc_code, float LTC2991_single_ended_lsb)
Calculates the LTC2991 Vcc voltage.
Definition: LTC2991.cpp:201
Header File for Linduino Libraries and Demo Code.
int8_t LTC2991_adc_read(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid)
Reads a 14-bit adc_code from LTC2991.
Definition: LTC2991.cpp:76
float LTC2991_code_to_diode_voltage(int16_t adc_code, float LTC2991_diode_voltage_lsb)
Calcultates the LTC2991 diode voltage.
Definition: LTC2991.cpp:247
int8_t LTC2991_register_write(uint8_t i2c_address, uint8_t register_address, uint8_t register_data)
Write one byte to an LTC2991 register.
Definition: LTC2991.cpp:163
float LTC2991_code_to_differential_voltage(int16_t adc_code, float LTC2991_differential_lsb)
Calculates the LTC2991 differential input voltage.
Definition: LTC2991.cpp:216
float LTC2991_code_to_single_ended_voltage(int16_t adc_code, float LTC2991_single_ended_lsb)
Calculates the LTC2991 single-ended input voltages.
Definition: LTC2991.cpp:186
int8_t i2c_write_byte_data(uint8_t address, uint8_t command, uint8_t value)
Write a byte of data to register specified by "command".
Definition: LT_I2C.cpp:155
#define LTC2991_STATUS_LOW_REG
Data_Valid Bits(V1 Through V8)
Definition: LTC2991.h:172
long timeout
int8_t i2c_read_word_data(uint8_t address, uint8_t command, uint16_t *value)
Read a 16-bit word of data from register specified by "command".
Definition: LT_I2C.cpp:172
LT_I2C: Routines to communicate with ATmega328P&#39;s hardware I2C port.
int8_t LTC2991_adc_read_new_data(uint8_t i2c_address, uint8_t msb_register_address, int16_t *adc_code, int8_t *data_valid, uint16_t timeout)
Reads new data (even after a mode change) by flushing old data and waiting for the data_valid bit to ...
Definition: LTC2991.cpp:142
int8_t LTC2991_register_read(uint8_t i2c_address, uint8_t register_address, uint8_t *register_data)
Reads an 8-bit register from the LTC2991 using the standard repeated start format.
Definition: LTC2991.cpp:153
static float voltage
Definition: DC2289AA.ino:71
float LTC2991_temperature(int16_t adc_code, float LTC2991_temperature_lsb, boolean unit)
Calculates the LTC2991 temperature.
Definition: LTC2991.cpp:230
LTC2991: 14-bit ADC octal I2C voltage, current, and temperature monitor.
#define LTC2991_STATUS_HIGH_REG
Data_valid bits.
Definition: LTC2991.h:173
static uint32_t adc_code
Definition: DC2071AA.ino:113