Maxim Integrated / MAX31723_Digital_Temperature_Sensor

C++ driver software code for Maxim Integrated MAX31723/MAX31722 device temperature sensor. The MAX31723 provides 9 to 12 bits of resolution.

Dependents:   MAX31723_Thermostat_Thermometer_Sensor

max31723.cpp@4:ac75d4d62471, 2019-01-30 (annotated)

Committer:
phonemacro
Date:
Wed Jan 30 02:13:05 2019 +0000
Revision:
4:ac75d4d62471
Parent:
3:f39791139435
Child:
5:8e70ec0923e2
correct calculations for signed temperatures

Who changed what in which revision?

UserRevisionLine numberNew contents of line
phonemacro 0:4a3d6ac5042d 1 /*******************************************************************************
phonemacro 0:4a3d6ac5042d 2 * Copyright (C) 2019 Maxim Integrated Products, Inc., All Rights Reserved.
phonemacro 0:4a3d6ac5042d 3 *
phonemacro 0:4a3d6ac5042d 4 * Permission is hereby granted, free of charge, to any person obtaining a
phonemacro 0:4a3d6ac5042d 5 * copy of this software and associated documentation files (the "Software"),
phonemacro 0:4a3d6ac5042d 6 * to deal in the Software without restriction, including without limitation
phonemacro 0:4a3d6ac5042d 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
phonemacro 0:4a3d6ac5042d 8 * and/or sell copies of the Software, and to permit persons to whom the
phonemacro 0:4a3d6ac5042d 9 * Software is furnished to do so, subject to the following conditions:
phonemacro 0:4a3d6ac5042d 10 *
phonemacro 0:4a3d6ac5042d 11 * The above copyright notice and this permission notice shall be included
phonemacro 0:4a3d6ac5042d 12 * in all copies or substantial portions of the Software.
phonemacro 0:4a3d6ac5042d 13 *
phonemacro 0:4a3d6ac5042d 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
phonemacro 0:4a3d6ac5042d 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
phonemacro 0:4a3d6ac5042d 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
phonemacro 0:4a3d6ac5042d 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
phonemacro 0:4a3d6ac5042d 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
phonemacro 0:4a3d6ac5042d 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
phonemacro 0:4a3d6ac5042d 20 * OTHER DEALINGS IN THE SOFTWARE.
phonemacro 0:4a3d6ac5042d 21 *
phonemacro 0:4a3d6ac5042d 22 * Except as contained in this notice, the name of Maxim Integrated
phonemacro 0:4a3d6ac5042d 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
phonemacro 0:4a3d6ac5042d 24 * Products, Inc. Branding Policy.
phonemacro 0:4a3d6ac5042d 25 *
phonemacro 0:4a3d6ac5042d 26 * The mere transfer of this software does not imply any licenses
phonemacro 0:4a3d6ac5042d 27 * of trade secrets, proprietary technology, copyrights, patents,
phonemacro 0:4a3d6ac5042d 28 * trademarks, maskwork rights, or any other form of intellectual
phonemacro 0:4a3d6ac5042d 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
phonemacro 0:4a3d6ac5042d 30 * ownership rights.
phonemacro 0:4a3d6ac5042d 31 *******************************************************************************
phonemacro 0:4a3d6ac5042d 32 */
phonemacro 0:4a3d6ac5042d 33 #include "max31723.h"
phonemacro 3:f39791139435 34
phonemacro 3:f39791139435 35 union max31723_raw_data {
phonemacro 3:f39791139435 36 struct {
phonemacro 3:f39791139435 37 uint8_t lsb;
phonemacro 3:f39791139435 38 uint8_t msb;
phonemacro 3:f39791139435 39 };
phonemacro 4:ac75d4d62471 40 uint16_t uwrd;
phonemacro 4:ac75d4d62471 41 int16_t swrd;
phonemacro 3:f39791139435 42 };
phonemacro 0:4a3d6ac5042d 43
phonemacro 0:4a3d6ac5042d 44 MAX31723::MAX31723(SPI &spi, DigitalOut &ce_pin) : m_spi(spi), m_chip_enable(ce_pin)
phonemacro 0:4a3d6ac5042d 45 {
phonemacro 0:4a3d6ac5042d 46 m_chip_enable = 0;
phonemacro 0:4a3d6ac5042d 47 }
phonemacro 0:4a3d6ac5042d 48
phonemacro 0:4a3d6ac5042d 49 int MAX31723::write_reg(uint8_t val, uint8_t reg)
phonemacro 0:4a3d6ac5042d 50 {
phonemacro 4:ac75d4d62471 51 if (reg == (MAX31723_REG_CFG | MAX31723_WRITE_MASK) ||
phonemacro 4:ac75d4d62471 52 (reg >= (MAX31723_REG_TRIP_HI_LSB | MAX31723_WRITE_MASK) &&
phonemacro 4:ac75d4d62471 53 reg <= (MAX31723_REG_MAX | MAX31723_WRITE_MASK)) ) {
phonemacro 4:ac75d4d62471 54 m_chip_enable = 1;
phonemacro 4:ac75d4d62471 55 m_spi.write(reg);
phonemacro 4:ac75d4d62471 56 m_spi.write(val);
phonemacro 4:ac75d4d62471 57 m_chip_enable = 0;
phonemacro 4:ac75d4d62471 58 return MAX31723_NO_ERROR;
phonemacro 4:ac75d4d62471 59 } else {
phonemacro 4:ac75d4d62471 60 printf("Input write_reg is invalid, 0x%02X \r\n", reg);
phonemacro 4:ac75d4d62471 61 return MAX31723_ERROR;
phonemacro 4:ac75d4d62471 62 }
phonemacro 0:4a3d6ac5042d 63 }
phonemacro 0:4a3d6ac5042d 64
phonemacro 0:4a3d6ac5042d 65 int MAX31723::read_reg(uint8_t &val, uint8_t reg)
phonemacro 0:4a3d6ac5042d 66 {
phonemacro 4:ac75d4d62471 67 if (reg <= MAX31723_REG_MAX) {
phonemacro 4:ac75d4d62471 68 m_chip_enable = 1;
phonemacro 4:ac75d4d62471 69 wait(.001);
phonemacro 4:ac75d4d62471 70 m_spi.write(reg);
phonemacro 4:ac75d4d62471 71 val = m_spi.write(0);
phonemacro 4:ac75d4d62471 72 m_chip_enable = 0;
phonemacro 4:ac75d4d62471 73 return MAX31723_NO_ERROR;
phonemacro 4:ac75d4d62471 74 } else {
phonemacro 4:ac75d4d62471 75 printf("Input read_reg is invalid, 0x%02X \r\n", reg);
phonemacro 4:ac75d4d62471 76 return MAX31723_ERROR;
phonemacro 4:ac75d4d62471 77 }
phonemacro 0:4a3d6ac5042d 78 }
phonemacro 0:4a3d6ac5042d 79
phonemacro 3:f39791139435 80 int MAX31723::perform_one_shot(uint8_t resolution, uint8_t interrupt_mode)
phonemacro 0:4a3d6ac5042d 81 {
phonemacro 2:7a20e65da621 82 if (resolution <= MAX31723_CFG_RESOLUTION_12BIT) {
phonemacro 2:7a20e65da621 83 write_reg(0, MAX31723_REG_CFG | MAX31723_WRITE_MASK);
phonemacro 3:f39791139435 84 write_reg(interrupt_mode | MAX31723_CFG_1SHOT |
phonemacro 2:7a20e65da621 85 resolution | MAX31723_CFG_STANDBY,
phonemacro 0:4a3d6ac5042d 86 MAX31723_REG_CFG | MAX31723_WRITE_MASK);
phonemacro 2:7a20e65da621 87 } else
phonemacro 0:4a3d6ac5042d 88 return MAX31723_ERROR;
phonemacro 0:4a3d6ac5042d 89 return MAX31723_NO_ERROR;
phonemacro 0:4a3d6ac5042d 90 }
phonemacro 0:4a3d6ac5042d 91
phonemacro 3:f39791139435 92 int MAX31723::perform_one_shot_int(uint8_t resolution)
phonemacro 0:4a3d6ac5042d 93 {
phonemacro 3:f39791139435 94 int ret;
phonemacro 3:f39791139435 95 ret = perform_one_shot(resolution, MAX31723_CFG_TM_MODE_INTERRUPT);
phonemacro 3:f39791139435 96 return ret;
phonemacro 3:f39791139435 97 }
phonemacro 3:f39791139435 98
phonemacro 3:f39791139435 99 int MAX31723::perform_one_shot_comparator(uint8_t resolution)
phonemacro 3:f39791139435 100 {
phonemacro 3:f39791139435 101 int ret;
phonemacro 3:f39791139435 102 ret = perform_one_shot(resolution, 0);
phonemacro 3:f39791139435 103 return ret;
phonemacro 0:4a3d6ac5042d 104 }
phonemacro 0:4a3d6ac5042d 105
phonemacro 3:f39791139435 106 uint8_t MAX31723::read_cfg()
phonemacro 3:f39791139435 107 {
phonemacro 3:f39791139435 108 uint8_t cfg;
phonemacro 3:f39791139435 109 read_reg(cfg, MAX31723_REG_CFG);
phonemacro 3:f39791139435 110 return cfg;
phonemacro 3:f39791139435 111 }
phonemacro 3:f39791139435 112
phonemacro 3:f39791139435 113 float MAX31723::read_reg_as_temperature(uint8_t reg)
phonemacro 3:f39791139435 114 {
phonemacro 3:f39791139435 115 max31723_raw_data raw;
phonemacro 3:f39791139435 116 float temperature;
phonemacro 3:f39791139435 117 if (reg >= MAX31723_REG_TEMP_LSB && reg <= MAX31723_REG_MAX) {
phonemacro 3:f39791139435 118 read_reg(raw.lsb, reg);
phonemacro 3:f39791139435 119 read_reg(raw.msb, reg+1);
phonemacro 4:ac75d4d62471 120 raw.swrd = raw.swrd >> MAX31723_UNUSED_BITS;
phonemacro 4:ac75d4d62471 121 temperature = raw.swrd * MAX31723_CF_LSB;
phonemacro 3:f39791139435 122 return temperature;
phonemacro 3:f39791139435 123 } else {
phonemacro 3:f39791139435 124 printf("Input read_registers_as_temperature is invalid, %d r\n",
phonemacro 3:f39791139435 125 reg);
phonemacro 3:f39791139435 126 return 0;
phonemacro 3:f39791139435 127 }
phonemacro 3:f39791139435 128 }
phonemacro 0:4a3d6ac5042d 129
phonemacro 0:4a3d6ac5042d 130 float MAX31723::celsius_to_fahrenheit(float temp_c)
phonemacro 0:4a3d6ac5042d 131 {
phonemacro 0:4a3d6ac5042d 132 float temp_f;
phonemacro 0:4a3d6ac5042d 133 temp_f = ((temp_c * 9)/5) + 32;
phonemacro 0:4a3d6ac5042d 134 return temp_f;
phonemacro 0:4a3d6ac5042d 135 }
phonemacro 0:4a3d6ac5042d 136
phonemacro 0:4a3d6ac5042d 137 MAX31723::~MAX31723(void)
phonemacro 0:4a3d6ac5042d 138 {
phonemacro 0:4a3d6ac5042d 139 //empty block
phonemacro 0:4a3d6ac5042d 140 }
phonemacro 0:4a3d6ac5042d 141