Maxim Integrated / MAX31875_Temperature_Sensor_Low_Power

C code and C++ library, driver software for the low-power small WLP package MAX31875 temperature sensor. Code supports one-shot, shut-down/standby, hysteresis, alarm limits.

Dependents:   MAX31875_Temperature_Sensor_Small_WLP Click-Sensor-MAX31875 NuMaker-mbed-Sensor-MAX31875

max31875_c.cpp@6:61f3693edd6c, 2019-02-13 (annotated)

Committer:
phonemacro
Date:
Wed Feb 13 22:17:06 2019 +0000
Revision:
6:61f3693edd6c
Parent:
4:a27a0ee318bd 
correct initialization in write_trip_low, high.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
phonemacro 3:3528e660168c 1 /*******************************************************************************
phonemacro 3:3528e660168c 2 * Copyright (C) 2019 Maxim Integrated Products, Inc., All Rights Reserved.
phonemacro 3:3528e660168c 3 *
phonemacro 3:3528e660168c 4 * Permission is hereby granted, free of charge, to any person obtaining a
phonemacro 3:3528e660168c 5 * copy of this software and associated documentation files (the "Software"),
phonemacro 3:3528e660168c 6 * to deal in the Software without restriction, including without limitation
phonemacro 3:3528e660168c 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
phonemacro 3:3528e660168c 8 * and/or sell copies of the Software, and to permit persons to whom the
phonemacro 3:3528e660168c 9 * Software is furnished to do so, subject to the following conditions:
phonemacro 3:3528e660168c 10 *
phonemacro 3:3528e660168c 11 * The above copyright notice and this permission notice shall be included
phonemacro 3:3528e660168c 12 * in all copies or substantial portions of the Software.
phonemacro 3:3528e660168c 13 *
phonemacro 3:3528e660168c 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
phonemacro 3:3528e660168c 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
phonemacro 3:3528e660168c 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
phonemacro 3:3528e660168c 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
phonemacro 3:3528e660168c 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
phonemacro 3:3528e660168c 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
phonemacro 3:3528e660168c 20 * OTHER DEALINGS IN THE SOFTWARE.
phonemacro 3:3528e660168c 21 *
phonemacro 3:3528e660168c 22 * Except as contained in this notice, the name of Maxim Integrated
phonemacro 3:3528e660168c 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
phonemacro 3:3528e660168c 24 * Products, Inc. Branding Policy.
phonemacro 3:3528e660168c 25 *
phonemacro 3:3528e660168c 26 * The mere transfer of this software does not imply any licenses
phonemacro 3:3528e660168c 27 * of trade secrets, proprietary technology, copyrights, patents,
phonemacro 3:3528e660168c 28 * trademarks, maskwork rights, or any other form of intellectual
phonemacro 3:3528e660168c 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
phonemacro 3:3528e660168c 30 * ownership rights.
phonemacro 3:3528e660168c 31 *******************************************************************************
phonemacro 3:3528e660168c 32 */
phonemacro 3:3528e660168c 33 #include "max31875.h"
phonemacro 3:3528e660168c 34 #include "max31875_c.h"
phonemacro 3:3528e660168c 35 #include "mbed.h"
phonemacro 3:3528e660168c 36 // #include "USBSerial.h"
phonemacro 3:3528e660168c 37
phonemacro 3:3528e660168c 38
phonemacro 3:3528e660168c 39 /******************************************************************************/
phonemacro 3:3528e660168c 40 /* C version for MAX31875 driver */
phonemacro 3:3528e660168c 41 /******************************************************************************/
phonemacro 3:3528e660168c 42
phonemacro 3:3528e660168c 43 /* @var max31875_write_address, max31875_read_address
phonemacro 3:3528e660168c 44 * @brief I2C address
phonemacro 3:3528e660168c 45 */
phonemacro 3:3528e660168c 46 uint8_t max31875_write_address, max31875_read_address;
phonemacro 3:3528e660168c 47 /* @var max31875_write_address, max31875_read_address
phonemacro 3:3528e660168c 48 * @brief max31875_extended_format
phonemacro 3:3528e660168c 49 */
phonemacro 3:3528e660168c 50 uint32_t max31875_extended_format;
phonemacro 3:3528e660168c 51
phonemacro 3:3528e660168c 52 int max31875_init(uint8_t slave_address)
phonemacro 3:3528e660168c 53 {
phonemacro 3:3528e660168c 54 max31875_write_address = (slave_address <<1);
phonemacro 3:3528e660168c 55 max31875_read_address = ((slave_address << 1) | 1);
phonemacro 3:3528e660168c 56 max31875_extended_format = 0;
phonemacro 3:3528e660168c 57 return MAX31875_NO_ERROR;
phonemacro 3:3528e660168c 58 }
phonemacro 3:3528e660168c 59
phonemacro 3:3528e660168c 60
phonemacro 3:3528e660168c 61 /******************************************************************************/
phonemacro 3:3528e660168c 62 int max31875_read_reg(uint16_t *value, char reg, I2C &i2c_bus)
phonemacro 3:3528e660168c 63 {
phonemacro 3:3528e660168c 64 int32_t ret;
phonemacro 3:3528e660168c 65 char data[2] = {0, 0};
phonemacro 3:3528e660168c 66 max31875_raw_data tmp;
phonemacro 3:3528e660168c 67
phonemacro 3:3528e660168c 68 if (reg <= MAX31875_REG_MAX) {
phonemacro 3:3528e660168c 69 /* write to the Register Select */
phonemacro 3:3528e660168c 70 ret = i2c_bus.write(max31875_write_address, &reg, 1, true);
phonemacro 3:3528e660168c 71 /* read the two bytes of data */
phonemacro 3:3528e660168c 72 if (ret == 0) {
phonemacro 3:3528e660168c 73 ret = i2c_bus.read(max31875_read_address, data, 2, false);
phonemacro 3:3528e660168c 74 if (ret == 0) {
phonemacro 4:a27a0ee318bd 75 tmp.msb = data[0];
phonemacro 4:a27a0ee318bd 76 tmp.lsb = data[1];
phonemacro 4:a27a0ee318bd 77 *value = tmp.uwrd;
phonemacro 3:3528e660168c 78 return MAX31875_NO_ERROR;
phonemacro 3:3528e660168c 79 } else {
phonemacro 3:3528e660168c 80 printf(
phonemacro 3:3528e660168c 81 "%s: failed to read data: ret: %d\r\n", __func__, ret);
phonemacro 3:3528e660168c 82 }
phonemacro 3:3528e660168c 83 } else {
phonemacro 3:3528e660168c 84 printf("%s: failed to write to Register Select: ret: %d\r\n",
phonemacro 3:3528e660168c 85 __func__, ret);
phonemacro 3:3528e660168c 86 }
phonemacro 3:3528e660168c 87 } else {
phonemacro 3:3528e660168c 88 printf("%s: register address is not correct: register: %d\r\n",
phonemacro 3:3528e660168c 89 __func__, reg);
phonemacro 3:3528e660168c 90 }
phonemacro 3:3528e660168c 91 return MAX31875_ERROR;
phonemacro 3:3528e660168c 92 }
phonemacro 3:3528e660168c 93
phonemacro 3:3528e660168c 94 float max31875_read_reg_as_temperature(uint8_t reg, I2C &i2c_bus)
phonemacro 3:3528e660168c 95 {
phonemacro 3:3528e660168c 96 max31875_raw_data tmp;
phonemacro 3:3528e660168c 97 float temperature;
phonemacro 3:3528e660168c 98 if (reg == MAX31875_REG_TEMPERATURE ||
phonemacro 4:a27a0ee318bd 99 reg == MAX31875_REG_THYST_LOW_TRIP || reg == MAX31875_REG_TOS_HIGH_TRIP) {
phonemacro 3:3528e660168c 100 max31875_read_reg(&tmp.uwrd, reg, i2c_bus);
phonemacro 4:a27a0ee318bd 101 temperature = (float)tmp.magnitude_bits;
phonemacro 3:3528e660168c 102 if (max31875_extended_format)
phonemacro 3:3528e660168c 103 temperature *= MAX31875_CF_EXTENDED_FORMAT;
phonemacro 3:3528e660168c 104 else
phonemacro 3:3528e660168c 105 temperature *= MAX31875_CF_NORMAL_FORMAT;
phonemacro 4:a27a0ee318bd 106 if (tmp.sign_bit)
phonemacro 4:a27a0ee318bd 107 temperature = -temperature;
phonemacro 4:a27a0ee318bd 108 return temperature;
phonemacro 4:a27a0ee318bd 109
phonemacro 3:3528e660168c 110 return temperature;
phonemacro 3:3528e660168c 111 } else {
phonemacro 3:3528e660168c 112 printf("%s: register is invalid, %d r\n", __func__, reg);
phonemacro 3:3528e660168c 113 return 0;
phonemacro 3:3528e660168c 114 }
phonemacro 3:3528e660168c 115 }
phonemacro 3:3528e660168c 116
phonemacro 3:3528e660168c 117
phonemacro 3:3528e660168c 118 /******************************************************************************/
phonemacro 3:3528e660168c 119 int max31875_write_reg(uint16_t value, char reg, I2C &i2c_bus)
phonemacro 3:3528e660168c 120 {
phonemacro 3:3528e660168c 121 int32_t ret;
phonemacro 3:3528e660168c 122 char cmd[3];
phonemacro 3:3528e660168c 123 max31875_raw_data tmp;
phonemacro 3:3528e660168c 124
phonemacro 3:3528e660168c 125 if (reg >= MAX31875_REG_CONFIGURATION && reg <= MAX31875_REG_MAX) {
phonemacro 3:3528e660168c 126 cmd[0] = reg;
phonemacro 3:3528e660168c 127 tmp.uwrd = value;
phonemacro 3:3528e660168c 128 cmd[1] = tmp.msb;
phonemacro 3:3528e660168c 129 cmd[2] = tmp.lsb;
phonemacro 3:3528e660168c 130 ret = i2c_bus.write(max31875_write_address, cmd, 3, false);
phonemacro 3:3528e660168c 131 if (ret == 0) {
phonemacro 4:a27a0ee318bd 132 if (MAX31875_REG_CONFIGURATION == reg) {
phonemacro 3:3528e660168c 133 max31875_extended_format = 0;
phonemacro 4:a27a0ee318bd 134 if (tmp.uwrd & MAX31875_CFG_EXTENDED_FORMAT)
phonemacro 4:a27a0ee318bd 135 max31875_extended_format = 1;
phonemacro 4:a27a0ee318bd 136 }
phonemacro 3:3528e660168c 137 return MAX31875_NO_ERROR;
phonemacro 3:3528e660168c 138 } else {
phonemacro 3:3528e660168c 139 printf("%s: I2C write error %d\r\n",__func__, ret);
phonemacro 3:3528e660168c 140 return MAX31875_ERROR;
phonemacro 3:3528e660168c 141 }
phonemacro 3:3528e660168c 142 } else {
phonemacro 3:3528e660168c 143 printf("%s: register value invalid %x\r\n",__func__, reg);
phonemacro 3:3528e660168c 144 return MAX31875_ERROR;
phonemacro 3:3528e660168c 145 }
phonemacro 3:3528e660168c 146 }
phonemacro 3:3528e660168c 147
phonemacro 3:3528e660168c 148
phonemacro 3:3528e660168c 149 int max31875_write_cfg(uint16_t cfg, I2C &i2c_bus)
phonemacro 3:3528e660168c 150 {
phonemacro 3:3528e660168c 151 return max31875_write_reg(cfg, MAX31875_REG_CONFIGURATION, i2c_bus);
phonemacro 3:3528e660168c 152 }
phonemacro 3:3528e660168c 153
phonemacro 3:3528e660168c 154
phonemacro 3:3528e660168c 155 int max31875_write_trip_low(float temperature, I2C &i2c_bus)
phonemacro 3:3528e660168c 156 {
phonemacro 3:3528e660168c 157 max31875_raw_data raw;
phonemacro 6:61f3693edd6c 158 raw.uwrd = 0;
phonemacro 4:a27a0ee318bd 159 if (temperature < 0) {
phonemacro 4:a27a0ee318bd 160 raw.sign_bit = 1;
phonemacro 4:a27a0ee318bd 161 temperature = -temperature;
phonemacro 4:a27a0ee318bd 162 }
phonemacro 3:3528e660168c 163 if (max31875_extended_format)
phonemacro 3:3528e660168c 164 temperature /= MAX31875_CF_EXTENDED_FORMAT;
phonemacro 3:3528e660168c 165 else
phonemacro 3:3528e660168c 166 temperature /= MAX31875_CF_NORMAL_FORMAT;
phonemacro 6:61f3693edd6c 167 raw.magnitude_bits = uint16_t(temperature);
phonemacro 4:a27a0ee318bd 168 return max31875_write_reg(raw.uwrd, MAX31875_REG_THYST_LOW_TRIP, i2c_bus);
phonemacro 3:3528e660168c 169 }
phonemacro 3:3528e660168c 170
phonemacro 3:3528e660168c 171
phonemacro 3:3528e660168c 172 int max31875_write_trip_high(float temperature, I2C &i2c_bus)
phonemacro 3:3528e660168c 173 {
phonemacro 3:3528e660168c 174 max31875_raw_data raw;
phonemacro 6:61f3693edd6c 175 raw.uwrd = 0;
phonemacro 4:a27a0ee318bd 176 if (temperature < 0) {
phonemacro 4:a27a0ee318bd 177 raw.sign_bit = 1;
phonemacro 4:a27a0ee318bd 178 temperature = -temperature;
phonemacro 4:a27a0ee318bd 179 }
phonemacro 3:3528e660168c 180 if (max31875_extended_format)
phonemacro 3:3528e660168c 181 temperature /= MAX31875_CF_EXTENDED_FORMAT;
phonemacro 3:3528e660168c 182 else
phonemacro 3:3528e660168c 183 temperature /= MAX31875_CF_NORMAL_FORMAT;
phonemacro 6:61f3693edd6c 184 raw.magnitude_bits = uint16_t(temperature);
phonemacro 4:a27a0ee318bd 185 return max31875_write_reg(raw.uwrd, MAX31875_REG_TOS_HIGH_TRIP, i2c_bus);
phonemacro 3:3528e660168c 186 }
phonemacro 3:3528e660168c 187
phonemacro 3:3528e660168c 188
phonemacro 3:3528e660168c 189 float max31875_celsius_to_fahrenheit(float temp_c)
phonemacro 3:3528e660168c 190 {
phonemacro 3:3528e660168c 191 float temp_f;
phonemacro 3:3528e660168c 192 temp_f = ((temp_c * 9)/5) + 32;
phonemacro 3:3528e660168c 193 return temp_f;
phonemacro 3:3528e660168c 194 }