eiaro/max31856

# API Reference ## Header files - [include/max31856.h](#file-includemax31856h) - [include/max31856.hpp](#file-includemax31856hpp) - [include/max31856_priv.h](#file-includemax31856_privh) ## File include/max31856.h ## Structures and Types | Type | Name | | ---: | :--- | | enum | [**max31856\_average\_t**](#enum-max31856_average_t) | | struct | [**max31856\_dev**](#struct-max31856_dev) _Structure representing a MAX31856 device instance._ | | typedef struct [**max31856\_dev**](#struct-max31856_dev) | [**max31856\_dev\_t**](#typedef-max31856_dev_t) _Structure representing a MAX31856 device instance._ | | enum | [**max31856\_oc\_detection\_t**](#enum-max31856_oc_detection_t) | | enum | [**max31856\_thermocouple\_type\_t**](#enum-max31856_thermocouple_type_t) | ## Functions | Type | Name | | ---: | :--- | | esp\_err\_t | [**max31856\_init**](#function-max31856_init) ([**max31856\_dev\_t**](#typedef-max31856_dev_t) \*data) _Initialize the MAX31856 device._ | | esp\_err\_t | [**max31856\_read\_cold\_junction**](#function-max31856_read_cold_junction) ([**max31856\_dev\_t**](#typedef-max31856_dev_t) \*data, float \*temperature) _Reads the cold junction temperature from the MAX31856 device._ | | esp\_err\_t | [**max31856\_read\_fault\_status**](#function-max31856_read_fault_status) ([**max31856\_dev\_t**](#typedef-max31856_dev_t) \*data, uint8\_t \*status) _Reads the fault status register from the MAX31856 device._ | | esp\_err\_t | [**max31856\_read\_thermocouple**](#function-max31856_read_thermocouple) ([**max31856\_dev\_t**](#typedef-max31856_dev_t) \*data, float \*temperature) _Reads the thermocouple temperature from the MAX31856 device._ | ## Structures and Types Documentation ### enum `max31856_average_t` ```c enum max31856_average_t { MAX31856_AVG_1 = 0b000, MAX31856_AVG_2 = 0b001, MAX31856_AVG_4 = 0b010, MAX31856_AVG_8 = 0b011, MAX31856_AVG_16 = 0b100 }; ``` ### struct `max31856_dev` _Structure representing a MAX31856 device instance._ This structure holds all relevant information and configuration required to interface with the MAX31856 thermocouple-to-digital converter. Populate and manage this structure when initializing and communicating with the device. Variables: - [**max31856\_average\_t**](#enum-max31856_average_t) averaging - bool filter_50hz - [**max31856\_oc\_detection\_t**](#enum-max31856_oc_detection_t) oc_detection - spi\_device\_handle\_t spi_dev - [**max31856\_thermocouple\_type\_t**](#enum-max31856_thermocouple_type_t) thermocouple_type - bool use_cold_junction ### typedef `max31856_dev_t` _Structure representing a MAX31856 device instance._ ```c typedef struct max31856_dev max31856_dev_t; ``` This structure holds all relevant information and configuration required to interface with the MAX31856 thermocouple-to-digital converter. Populate and manage this structure when initializing and communicating with the device. ### enum `max31856_oc_detection_t` ```c enum max31856_oc_detection_t { MAX31856_OC_DETECT_OFF = 0b00, MAX31856_OC_DETECT_1 = 0b01, MAX31856_OC_DETECT_2 = 0b10, MAX31856_OC_DETECT_3 = 0b11 }; ``` ### enum `max31856_thermocouple_type_t` ```c enum max31856_thermocouple_type_t { MAX31856_TC_TYPE_B = 0b0000, MAX31856_TC_TYPE_E = 0b0001, MAX31856_TC_TYPE_J = 0b0010, MAX31856_TC_TYPE_K = 0b0011, MAX31856_TC_TYPE_N = 0b0100, MAX31856_TC_TYPE_R = 0b0101, MAX31856_TC_TYPE_S = 0b0110, MAX31856_TC_TYPE_T = 0b0111 }; ``` ## Functions Documentation ### function `max31856_init` _Initialize the MAX31856 device._ ```c esp_err_t max31856_init ( max31856_dev_t *data ) ``` This function initializes the MAX31856 device structure and configures the necessary hardware interfaces. **Parameters:** * `data` Pointer to the MAX31856 device structure to initialize. **Returns:** * ESP\_OK on success * Appropriate error code from esp\_err\_t on failure ### function `max31856_read_cold_junction` _Reads the cold junction temperature from the MAX31856 device._ ```c esp_err_t max31856_read_cold_junction ( max31856_dev_t *data, float *temperature ) ``` This function retrieves the current cold junction (reference junction) temperature from the specified MAX31856 device and stores the result in the provided temperature pointer. **Parameters:** * `data` Pointer to the MAX31856 device structure. * `temperature` Pointer to a float variable where the temperature (in degrees Celsius) will be stored. **Returns:** * ESP\_OK on success * Appropriate esp\_err\_t error code otherwise ### function `max31856_read_fault_status` _Reads the fault status register from the MAX31856 device._ ```c esp_err_t max31856_read_fault_status ( max31856_dev_t *data, uint8_t *status ) ``` This function retrieves the current fault status from the MAX31856 thermocouple-to-digital converter and stores it in the provided status variable. **Parameters:** * `data` Pointer to the MAX31856 device structure. * `status` Pointer to a variable where the fault status byte will be stored. **Returns:** * ESP\_OK on success * Appropriate error code otherwise ### function `max31856_read_thermocouple` _Reads the thermocouple temperature from the MAX31856 device._ ```c esp_err_t max31856_read_thermocouple ( max31856_dev_t *data, float *temperature ) ``` This function communicates with the MAX31856 thermocouple-to-digital converter to retrieve the current thermocouple temperature measurement. **Parameters:** * `data` Pointer to the MAX31856 device structure. * `temperature` Pointer to a float variable where the measured temperature (in C) will be stored. **Returns:** * ESP\_OK on success * Appropriate esp\_err\_t error code otherwise ## File include/max31856.hpp ## File include/max31856_priv.h ## Functions | Type | Name | | ---: | :--- | | esp\_err\_t | [**max31856\_read**](#function-max31856_read) ([**max31856\_dev\_t**](#typedef-max31856_dev_t) \*data, uint8\_t addr, uint8\_t \*value) _Read a value from a specific register address of the MAX31856 device._ | | esp\_err\_t | [**max31856\_write**](#function-max31856_write) ([**max31856\_dev\_t**](#typedef-max31856_dev_t) \*data, uint8\_t addr, uint8\_t value) _Write a value to a specific register address of the MAX31856 device._ | ## Macros | Type | Name | | ---: | :--- | | define | [**GENMASK**](#define-genmask) (h, l) (((1UL << ((h) - (l) + 1)) - 1) << (l)) _Creates a contiguous bitmask spanning from bit position 'l' to 'h' (inclusive)._ | | define | [**MAX31856\_CJHF\_REG**](#define-max31856_cjhf_reg) 0x03 | | define | [**MAX31856\_CJLF\_REG**](#define-max31856_cjlf_reg) 0x04 | | define | [**MAX31856\_CJTH\_REG**](#define-max31856_cjth_reg) 0x0A | | define | [**MAX31856\_CJTL\_REG**](#define-max31856_cjtl_reg) 0x0B | | define | [**MAX31856\_CJTO\_REG**](#define-max31856_cjto_reg) 0x09 | | define | [**MAX31856\_CR0\_1SHOT**](#define-max31856_cr0_1shot) BIT(6) | | define | [**MAX31856\_CR0\_AUTOCONVERT**](#define-max31856_cr0_autoconvert) BIT(7) | | define | [**MAX31856\_CR0\_CJ**](#define-max31856_cr0_cj) BIT(3) | | define | [**MAX31856\_CR0\_FAULT**](#define-max31856_cr0_fault) BIT(2) | | define | [**MAX31856\_CR0\_OC\_MASK**](#define-max31856_cr0_oc_mask) [**GENMASK**](#define-genmask)(5, 4) | | define | [**MAX31856\_CR0\_OC\_SHIFT**](#define-max31856_cr0_oc_shift) 4 | | define | [**MAX31856\_CR0\_REG**](#define-max31856_cr0_reg) 0x00 | | define | [**MAX31856\_CR1\_AVERAGE\_MASK**](#define-max31856_cr1_average_mask) [**GENMASK**](#define-genmask)(6, 4) | | define | [**MAX31856\_CR1\_AVERAGE\_SHIFT**](#define-max31856_cr1_average_shift) 4 | | define | [**MAX31856\_CR1\_REG**](#define-max31856_cr1_reg) 0x01 | | define | [**MAX31856\_CR1\_TCTYPE\_MASK**](#define-max31856_cr1_tctype_mask) [**GENMASK**](#define-genmask)(3, 0) | | define | [**MAX31856\_LTCBH\_REG**](#define-max31856_ltcbh_reg) 0x0C | | define | [**MAX31856\_LTCBL\_REG**](#define-max31856_ltcbl_reg) 0x0E | | define | [**MAX31856\_LTCBM\_REG**](#define-max31856_ltcbm_reg) 0x0D | | define | [**MAX31856\_LTHFTH\_REG**](#define-max31856_lthfth_reg) 0x05 | | define | [**MAX31856\_LTHFTL\_REG**](#define-max31856_lthftl_reg) 0x06 | | define | [**MAX31856\_LTLFTH\_REG**](#define-max31856_ltlfth_reg) 0x07 | | define | [**MAX31856\_LTLFTL\_REG**](#define-max31856_ltlftl_reg) 0x08 | | define | [**MAX31856\_MASK\_REG**](#define-max31856_mask_reg) 0x02 | | define | [**MAX31856\_RD\_WR\_MASK**](#define-max31856_rd_wr_mask) BIT(7) | | define | [**MAX31856\_SR\_REG**](#define-max31856_sr_reg) 0x0F | ## Functions Documentation ### function `max31856_read` _Read a value from a specific register address of the MAX31856 device._ ```c esp_err_t max31856_read ( max31856_dev_t *data, uint8_t addr, uint8_t *value ) ``` This function reads a single byte value from the specified register address of the MAX31856 thermocouple-to-digital converter via SPI. **Parameters:** * `data` Pointer to the MAX31856 device structure. * `addr` Register address to read from. * `value` Pointer to store the read value. **Returns:** * ESP\_OK on success * Appropriate esp\_err\_t error code otherwise ### function `max31856_write` _Write a value to a specific register address of the MAX31856 device._ ```c esp_err_t max31856_write ( max31856_dev_t *data, uint8_t addr, uint8_t value ) ``` This function writes a single byte value to the specified register address of the MAX31856 thermocouple-to-digital converter via SPI. **Parameters:** * `data` Pointer to the MAX31856 device structure. * `addr` Register address to write to. * `value` Value to write to the register. **Returns:** * ESP\_OK on success * Appropriate esp\_err\_t error code otherwise ## Macros Documentation ### define `GENMASK` _Creates a contiguous bitmask spanning from bit position 'l' to 'h' (inclusive)._ ```c #define GENMASK ( h, l ) (((1UL << ((h) - (l) + 1)) - 1) << (l)) ``` This macro generates a value where bits in positions l through h are set to 1, and all other bits are set to 0. It's commonly used for masking specific bit fields within registers. **Parameters:** * `h` The high bit position (most significant bit of the mask) * `l` The low bit position (least significant bit of the mask) **Returns:** A value with bits set from position l to position h Example:[**GENMASK(3, 0)**](#define-genmask) produces 0b1111 (0xF)[**GENMASK(7, 4)**](#define-genmask) produces 0b11110000 (0xF0) ### define `MAX31856_CJHF_REG` ```c #define MAX31856_CJHF_REG 0x03 ``` ### define `MAX31856_CJLF_REG` ```c #define MAX31856_CJLF_REG 0x04 ``` ### define `MAX31856_CJTH_REG` ```c #define MAX31856_CJTH_REG 0x0A ``` ### define `MAX31856_CJTL_REG` ```c #define MAX31856_CJTL_REG 0x0B ``` ### define `MAX31856_CJTO_REG` ```c #define MAX31856_CJTO_REG 0x09 ``` ### define `MAX31856_CR0_1SHOT` ```c #define MAX31856_CR0_1SHOT BIT(6) ``` ### define `MAX31856_CR0_AUTOCONVERT` ```c #define MAX31856_CR0_AUTOCONVERT BIT(7) ``` ### define `MAX31856_CR0_CJ` ```c #define MAX31856_CR0_CJ BIT(3) ``` ### define `MAX31856_CR0_FAULT` ```c #define MAX31856_CR0_FAULT BIT(2) ``` ### define `MAX31856_CR0_OC_MASK` ```c #define MAX31856_CR0_OC_MASK GENMASK (5, 4) ``` ### define `MAX31856_CR0_OC_SHIFT` ```c #define MAX31856_CR0_OC_SHIFT 4 ``` ### define `MAX31856_CR0_REG` ```c #define MAX31856_CR0_REG 0x00 ``` ### define `MAX31856_CR1_AVERAGE_MASK` ```c #define MAX31856_CR1_AVERAGE_MASK GENMASK (6, 4) ``` ### define `MAX31856_CR1_AVERAGE_SHIFT` ```c #define MAX31856_CR1_AVERAGE_SHIFT 4 ``` ### define `MAX31856_CR1_REG` ```c #define MAX31856_CR1_REG 0x01 ``` ### define `MAX31856_CR1_TCTYPE_MASK` ```c #define MAX31856_CR1_TCTYPE_MASK GENMASK (3, 0) ``` ### define `MAX31856_LTCBH_REG` ```c #define MAX31856_LTCBH_REG 0x0C ``` ### define `MAX31856_LTCBL_REG` ```c #define MAX31856_LTCBL_REG 0x0E ``` ### define `MAX31856_LTCBM_REG` ```c #define MAX31856_LTCBM_REG 0x0D ``` ### define `MAX31856_LTHFTH_REG` ```c #define MAX31856_LTHFTH_REG 0x05 ``` ### define `MAX31856_LTHFTL_REG` ```c #define MAX31856_LTHFTL_REG 0x06 ``` ### define `MAX31856_LTLFTH_REG` ```c #define MAX31856_LTLFTH_REG 0x07 ``` ### define `MAX31856_LTLFTL_REG` ```c #define MAX31856_LTLFTL_REG 0x08 ``` ### define `MAX31856_MASK_REG` ```c #define MAX31856_MASK_REG 0x02 ``` ### define `MAX31856_RD_WR_MASK` ```c #define MAX31856_RD_WR_MASK BIT(7) ``` ### define `MAX31856_SR_REG` ```c #define MAX31856_SR_REG 0x0F ```

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