/* * MIT License * * Copyright (c) 2017 David Antliff * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ /** * @file ds18b20.h * @brief Interface definitions for the Maxim Integrated DS18B20 Programmable * Resolution 1-Wire Digital Thermometer device. * * This component provides structures and functions that are useful for communicating * with DS18B20 devices connected via a Maxim Integrated 1-Wire® bus. */ #ifndef DS18B20_H #define DS18B20_H #include "../esp32-owb/owb.h" #ifdef __cplusplus extern "C" { #endif /** * @brief Success and error codes. */ typedef enum { DS18B20_ERROR_UNKNOWN = -1, DS18B20_OK = 0, DS18B20_ERROR_DEVICE, ///< A device error occurred DS18B20_ERROR_CRC, ///< A CRC error occurred DS18B20_ERROR_OWB, ///< A One Wire Bus error occurred DS18B20_ERROR_NULL, ///< A parameter or value is NULL } DS18B20_ERROR; /** * @brief Symbols for the supported temperature resolution of the device. */ typedef enum { DS18B20_RESOLUTION_INVALID = -1, ///< Invalid resolution DS18B20_RESOLUTION_9_BIT = 9, ///< 9-bit resolution, LSB bits 2,1,0 undefined DS18B20_RESOLUTION_10_BIT = 10, ///< 10-bit resolution, LSB bits 1,0 undefined DS18B20_RESOLUTION_11_BIT = 11, ///< 11-bit resolution, LSB bit 0 undefined DS18B20_RESOLUTION_12_BIT = 12, ///< 12-bit resolution (default) } DS18B20_RESOLUTION; /** * @brief Structure containing information related to a single DS18B20 device connected * via a 1-Wire bus. */ typedef struct { bool init; ///< True if struct has been initialised, otherwise false bool solo; ///< True if device is intended to be the only one connected to the bus, otherwise false bool use_crc; ///< True if CRC checks are to be used when retrieving information from a device on the bus const OneWireBus * bus; ///< Pointer to 1-Wire bus information relevant to this device OneWireBus_ROMCode rom_code; ///< The ROM code used to address this device on the bus DS18B20_RESOLUTION resolution; ///< Temperature measurement resolution per reading } DS18B20_Info; /** * @brief Construct a new device info instance. * New instance should be initialised before calling other functions. * @return Pointer to new device info instance, or NULL if it cannot be created. */ DS18B20_Info * ds18b20_malloc(void); /** * @brief Delete an existing device info instance. * @param[in] ds18b20_info Pointer to device info instance. * @param[in,out] ds18b20_info Pointer to device info instance that will be freed and set to NULL. */ void ds18b20_free(DS18B20_Info ** ds18b20_info); /** * @brief Initialise a device info instance with the specified GPIO. * @param[in] ds18b20_info Pointer to device info instance. * @param[in] bus Pointer to initialised 1-Wire bus instance. * @param[in] rom_code Device-specific ROM code to identify a device on the bus. */ void ds18b20_init(DS18B20_Info * ds18b20_info, const OneWireBus * bus, OneWireBus_ROMCode rom_code); /** * @brief Initialise a device info instance with the specified GPIO as a solo device on the bus. * * This is subject to the requirement that this device is the ONLY device on the bus. * This allows for faster commands to be used without ROM code addressing. * * NOTE: if additional devices are added to the bus, operation will cease to work correctly. * * @param[in] ds18b20_info Pointer to device info instance. * @param[in] bus Pointer to initialised 1-Wire bus instance. * @param[in] rom_code Device-specific ROM code to identify a device on the bus. */ void ds18b20_init_solo(DS18B20_Info * ds18b20_info, const OneWireBus * bus); /** * @brief Enable or disable use of CRC checks on device communications. * @param[in] ds18b20_info Pointer to device info instance. * @param[in] use_crc True to enable CRC checks, false to disable. */ void ds18b20_use_crc(DS18B20_Info * ds18b20_info, bool use_crc); /** * @brief Set temperature measurement resolution. * * This programs the hardware to the specified resolution and sets the cached value to be the same. * If the program fails, the value currently in hardware is used to refresh the cache. * * @param[in] ds18b20_info Pointer to device info instance. * @param[in] resolution Selected resolution. * @return True if successful, otherwise false. */ bool ds18b20_set_resolution(DS18B20_Info * ds18b20_info, DS18B20_RESOLUTION resolution); /** * @brief Update and return the current temperature measurement resolution from the device. * @param[in] ds18b20_info Pointer to device info instance. * @return The currently configured temperature measurement resolution. */ DS18B20_RESOLUTION ds18b20_read_resolution(DS18B20_Info * ds18b20_info); /** * @brief Read 64-bit ROM code from device - only works when there is a single device on the bus. * @param[in] ds18b20_info Pointer to device info instance. * @return The 64-bit value read from the device's ROM. */ OneWireBus_ROMCode ds18b20_read_rom(DS18B20_Info * ds18b20_info); /** * @brief Start a temperature measurement conversion on a single device. * @param[in] ds18b20_info Pointer to device info instance. */ bool ds18b20_convert(const DS18B20_Info * ds18b20_info); /** * @brief Start temperature conversion on all connected devices. * * This should be followed by a sufficient delay to ensure all devices complete * their conversion before the measurements are read. * @param[in] bus Pointer to initialised bus instance. */ void ds18b20_convert_all(const OneWireBus * bus); /** * @brief Wait for the maximum conversion time according to the current resolution of the device. * @param[in] bus Pointer to initialised bus instance. * @return An estimate of the time elapsed, in milliseconds. Actual elapsed time may be greater. */ float ds18b20_wait_for_conversion(const DS18B20_Info * ds18b20_info); /** * @brief Read last temperature measurement from device. * * This is typically called after ds18b20_start_mass_conversion(), provided enough time * has elapsed to ensure that all devices have completed their conversions. * @param[in] ds18b20_info Pointer to device info instance. Must be initialised first. * @param[out] value Pointer to the measurement value returned by the device, in degrees Celsius. * @return DS18B20_OK if read is successful, otherwise error. */ DS18B20_ERROR ds18b20_read_temp(const DS18B20_Info * ds18b20_info, float * value); /** * @brief Convert, wait and read current temperature from device. * @param[in] ds18b20_info Pointer to device info instance. Must be initialised first. * @param[out] value Pointer to the measurement value returned by the device, in degrees Celsius. * @return DS18B20_OK if read is successful, otherwise error. */ DS18B20_ERROR ds18b20_convert_and_read_temp(const DS18B20_Info * ds18b20_info, float * value); #ifdef __cplusplus } #endif #endif // DS18B20_H