#ifndef DRIVER_DS18B20_H_ #define DRIVER_DS18B20_H_ #include "onewire.h" #ifdef __cplusplus extern "C" { #endif /** @file ds18b20.h * * Communicate with the DS18B20 family of one-wire temperature sensor ICs. * */ typedef onewire_addr_t ds18b20_addr_t; /** An address value which can be used to indicate "any device on the bus" */ #define DS18B20_ANY ONEWIRE_NONE /** Find the addresses of all DS18B20 devices on the bus. * * Scans the bus for all devices and places their addresses in the supplied * array. If there are more than `addr_count` devices on the bus, only the * first `addr_count` are recorded. * * @param pin The GPIO pin connected to the DS18B20 bus * @param addr_list A pointer to an array of ds18b20_addr_t values. This * will be populated with the addresses of the found * devices. * @param addr_count Number of slots in the `addr_list` array. At most this * many addresses will be returned. * * @returns The number of devices found. Note that this may be less than, * equal to, or more than `addr_count`, depending on how many DS18B20 devices * are attached to the bus. */ int ds18b20_scan_devices(int pin, ds18b20_addr_t *addr_list, int addr_count); /** Tell one or more sensors to perform a temperature measurement and * conversion (CONVERT_T) operation. This operation can take up to 750ms to * complete. * * If `wait=true`, this routine will automatically drive the pin high for the * necessary 750ms after issuing the command to ensure parasitically-powered * devices have enough power to perform the conversion operation (for * non-parasitically-powered devices, this is not necessary but does not * hurt). If `wait=false`, this routine will drive the pin high, but will * then return immediately. It is up to the caller to wait the requisite time * and then depower the bus using onewire_depower() or by issuing another * command once conversion is done. * * @param pin The GPIO pin connected to the DS18B20 device * @param addr The 64-bit address of the device on the bus. This can be set * to ::DS18B20_ANY to send the command to all devices on the bus * at the same time. * @param wait Whether to wait for the necessary 750ms for the DS18B20 to * finish performing the conversion before returning to the * caller (You will normally want to do this). * * @returns `true` if the command was successfully issued, or `false` on error. */ bool ds18b20_measure(int pin, ds18b20_addr_t addr, bool wait); /** Read the value from the last CONVERT_T operation. * * This should be called after ds18b20_measure() to fetch the result of the * temperature measurement. * * @param pin The GPIO pin connected to the DS18B20 device * @param addr The 64-bit address of the device to read. This can be set * to ::DS18B20_ANY to read any device on the bus (but note * that this will only work if there is exactly one device * connected, or they will corrupt each others' transmissions) * * @returns The temperature in degrees Celsius, or NaN if there was an error. */ float ds18b20_read_temperature(int pin, ds18b20_addr_t addr); /** Read the value from the last CONVERT_T operation for multiple devices. * * This should be called after ds18b20_measure() to fetch the result of the * temperature measurement. * * @param pin The GPIO pin connected to the DS18B20 bus * @param addr_list A list of addresses for devices to read. * @param addr_count The number of entries in `addr_list`. * @param result_list An array of floats to hold the returned temperature * values. It should have at least `addr_count` entries. * * @returns `true` if all temperatures were fetched successfully, or `false` * if one or more had errors (the temperature for erroring devices will be * returned as NaN). */ bool ds18b20_read_temp_multi(int pin, ds18b20_addr_t *addr_list, int addr_count, float *result_list); /** Perform a ds18b20_measure() followed by ds18b20_read_temperature() * * @param pin The GPIO pin connected to the DS18B20 device * @param addr The 64-bit address of the device to read. This can be set * to ::DS18B20_ANY to read any device on the bus (but note * that this will only work if there is exactly one device * connected, or they will corrupt each others' transmissions) * * @returns The temperature in degrees Celsius, or NaN if there was an error. */ float ds18b20_measure_and_read(int pin, ds18b20_addr_t addr); /** Perform a ds18b20_measure() followed by ds18b20_read_temp_multi() * * @param pin The GPIO pin connected to the DS18B20 bus * @param addr_list A list of addresses for devices to read. * @param addr_count The number of entries in `addr_list`. * @param result_list An array of floats to hold the returned temperature * values. It should have at least `addr_count` entries. * * @returns `true` if all temperatures were fetched successfully, or `false` * if one or more had errors (the temperature for erroring devices will be * returned as NaN). */ bool ds18b20_measure_and_read_multi(int pin, ds18b20_addr_t *addr_list, int addr_count, float *result_list); /** Read the scratchpad data for a particular DS18B20 device. * * This is not generally necessary to do directly. It is done automatically * as part of ds18b20_read_temperature(). * * @param pin The GPIO pin connected to the DS18B20 device * @param addr The 64-bit address of the device to read. This can be set * to ::DS18B20_ANY to read any device on the bus (but note * that this will only work if there is exactly one device * connected, or they will corrupt each others' transmissions) * @param buffer An 8-byte buffer to hold the read data. * * @returns `true` if the data was read successfully, or `false` on error. */ bool ds18b20_read_scratchpad(int pin, ds18b20_addr_t addr, uint8_t *buffer); // The following are obsolete/deprecated APIs typedef struct { uint8_t id; float value; } ds_sensor_t; // Scan all ds18b20 sensors on bus and return its amount. // Result are saved in array of ds_sensor_t structure. uint8_t ds18b20_read_all(uint8_t pin, ds_sensor_t *result); // This method is just to demonstrate how to read // temperature from single dallas chip. float ds18b20_read_single(uint8_t pin); #ifdef __cplusplus } #endif #endif /* DRIVER_DS18B20_H_ */