1 /* 2 * Copyright (c) 2022 HAW Hamburg FTZ-DIWIP 3 * 4 * SPDX-License-Identifier: Apache-2.0 5 */ 6 #ifndef _MAX31865_H 7 #define _MAX31865_H 8 9 #define DT_DRV_COMPAT maxim_max31865 10 11 #include <math.h> 12 13 #include <zephyr/drivers/sensor.h> 14 #include <zephyr/drivers/sensor/max31865.h> 15 #include <zephyr/drivers/spi.h> 16 #include <zephyr/kernel.h> 17 #include <zephyr/logging/log.h> 18 #include <zephyr/sys/util_macro.h> 19 #include <zephyr/sys/byteorder.h> 20 LOG_MODULE_REGISTER(MAX31865, CONFIG_SENSOR_LOG_LEVEL); 21 22 #define MAX31865_FAULT_HIGH_THRESHOLD BIT(7) 23 #define MAX31865_FAULT_LOW_THRESHOLD BIT(6) 24 #define MAX31865_FAULT_REFIN BIT(5) 25 #define MAX31865_FAULT_REFIN_FORCE BIT(4) 26 #define MAX31865_FAULT_RTDIN_FORCE BIT(3) 27 #define MAX31865_FAULT_VOLTAGE BIT(2) 28 29 #define MAX31865_FAULT_DETECTION_NONE (0x00 << 2) 30 #define MAX31865_FAULT_DETECTION_AUTO (0x01 << 2) 31 #define MAX31865_FAULT_DETECTION_MANUAL_1 (0x02 << 2) 32 #define MAX31865_FAULT_DETECTION_MANUAL_2 (0x03 << 2) 33 34 /* Read Register Address */ 35 #define REG_CONFIG 0x00 36 #define REG_RTD_MSB 0x01 37 #define REG_RTD_LSB 0x02 38 #define REG_HIGH_FAULT_THR_MSB 0x03 39 #define REG_HIGH_FAULT_THR_LSB 0x04 40 #define REG_LOW_FAULT_THR_MSB 0x05 41 #define REG_LOW_FAULT_THR_LSB 0x06 42 #define REG_FAULT_STATUS 0x07 43 #define WR(reg) ((reg) | 0x80) 44 45 /* Bitmask to clear fault status bits D5, D3, and D2 */ 46 #define FAULT_BITS_CLEAR_MASK 0x2C 47 48 /** 49 * RTD data, RTD current, and measurement reference 50 * voltage. The ITS-90 standard is used; other RTDs 51 * may have coefficients defined by the DIN 43760 or 52 * the U.S. Industrial (American) standard. 53 */ 54 55 #define RTD_A_ITS90 3.9080e-3 56 #define RTD_A_USINDUSTRIAL 3.9692e-3 57 #define RTD_A_DIN43760 3.9848e-3 58 #define RTD_B_ITS90 -5.870e-7 59 #define RTD_B_USINDUSTRIAL -5.8495e-7 60 #define RTD_B_DIN43760 -5.8019e-7 61 62 /** 63 * RTD coefficient C is required only for temperatures 64 * below 0 deg. C. The selected RTD coefficient set 65 * is specified below. 66 */ 67 #define RTD_A (RTD_A_ITS90) 68 #define RTD_B (RTD_B_ITS90) 69 70 /* 71 * For under zero, taken from 72 * https://www.analog.com/media/en/technical-documentation/application-notes/AN709_0.pdf 73 */ 74 static const double RTD_C[6] = {-242.02, 2.2228, 2.5859e-3, 4.8260e-6, 2.8183e-8, 1.5243e-10}; 75 76 struct max31865_data { 77 double temperature; 78 uint8_t config_control_bits; 79 }; 80 81 /** 82 * Configuration struct to the MAX31865. 83 */ 84 struct max31865_config { 85 const struct spi_dt_spec spi; 86 uint16_t resistance_at_zero; 87 uint16_t resistance_reference; 88 bool conversion_mode; 89 bool one_shot; 90 bool three_wire; 91 uint8_t fault_cycle; 92 bool filter_50hz; 93 uint16_t low_threshold; 94 uint16_t high_threshold; 95 }; 96 97 /* Bit manipulation macros */ 98 #define TESTBIT(data, pos) ((0u == (data & BIT(pos))) ? 0u : 1u) 99 100 #endif 101
