add DS18B20 temperature sensor library from thermo-regulator project
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lib/sensor_ds18b20.c
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lib/sensor_ds18b20.c
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/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** library for Maxim DS18B20 digital temperature sensor (using 1-Wire protocol) (code)
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* @file sensor_ds18b20.c
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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* @note peripherals used: 1-Wire (timer @ref onewire_master_timer, GPIO @ref onewire_master_gpio)
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* @warning this library does not support parasite power mode and alarms
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*/
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/* standard libraries */
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#include <stdint.h> // standard integer types
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#include <stdbool.h> // boolean type
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#include <stdlib.h> // size_t definition
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#include <math.h> // NAN definition
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/* own libraries */
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#include "global.h" // help macros
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#include "onewire_master.h" // 1-Wire utilities
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#include "sensor_ds18b20.h" // own definitions
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/** remember number of DS18B20 sensors on 1-Wire bus for certain functions */
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uint64_t sensors = 0;
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/** remember if only DS18B20 sensors on 1-Wire bus for certain functions */
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bool only = false;
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/** remember code of last sensor **/
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uint64_t last = 0;
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void sensor_ds18b20_setup(void)
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{
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onewire_master_setup(); // setup 1-Wire peripheral to communicate with sensors on bus
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sensor_ds18b20_number(); // scan for sensor (remembers sensor number and exclusivity)
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}
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uint64_t sensor_ds18b20_number(void)
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{
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sensors = 0; // reset number
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only = true; // reset state
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uint64_t code = 0; // ROM code found (use 0 to start from scratch)
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bool more = true; // save if other additional slaves exist
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while (more) { // scan for all 1-Wire slaves
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if (!onewire_master_reset()) { // send reset to start communication
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return 0; // no slave presence detected
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}
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more = onewire_master_rom_search(&code, false); // get next slave ROM code (without alarm)
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if (0==code) { // error occurred
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return 0;
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}
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if (0x28==(code&0xff)) { // family code (8-LSb) for DS18B20 sensors is 0x28
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last = code; // save last found code
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sensors++; // we found an additional sensor
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} else {
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only = false; // we found a slave which is not a sensor
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}
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}
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return sensors;
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}
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bool sensor_ds18b20_only(void)
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{
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sensor_ds18b20_number(); // this also checks for exclusivity
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return only;
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}
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bool sensor_ds18b20_list(uint64_t* code)
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{
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if (!onewire_master_reset()) { // send reset to start communication
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return false; // no slave presence detected
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}
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onewire_master_rom_search(code, false); // get next code
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return (last!=*code); // verify if the last has been found
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}
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bool sensor_ds18b20_convert(uint64_t code)
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{
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if (0==code && !only) { // asked for broadcast but there are different slaves on bus
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return false; // broadcast not possible when there are also different slaves on bus
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}
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// send reset pulse
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if (!onewire_master_reset()) { // send reset to start communication
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return false; // no slave presence detected
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}
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// send ROM command to select slave(s)
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if (0==code) { // broadcast convert
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if (!onewire_master_rom_skip()) { // select all slaves
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return false; // ROM command failed
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}
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} else {
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if (!onewire_master_rom_match(code)) { // select specific slave
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return false; // ROM command failed
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}
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}
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// send convert T function command
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return onewire_master_function_read(0x44, NULL, 0);
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}
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float sensor_ds18b20_temperature(uint64_t code)
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{
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if (0==code && (sensors>1 || !only)) { // broadcast read requested
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return NAN; // this function is not possible when several sensors or other devices are present
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}
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// send reset pulse
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if (!onewire_master_reset()) { // send reset to start communication
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return NAN; // no slave presence detected
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}
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// send ROM command to select slave
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if (!onewire_master_rom_match(code)) { // select specific slave
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return NAN; // ROM command failed
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}
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// read scratchpad to get temperature (on byte 0 and 1)
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uint8_t scratchpad[9] = {0}; // to store read scratchpad
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if (!onewire_master_function_read(0xbe, scratchpad, sizeof(scratchpad)*8)) { // read complete scratchpad
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return NAN; // error occurred during read
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}
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// verify if data is valid
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if (onewire_master_crc(scratchpad, sizeof(scratchpad))) { // check CRC checksum
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return NAN; // data corrupted
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}
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// calculate temperature (stored as int16_t but on 0.125 C steps)
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return ((int16_t)(scratchpad[1]<<8)+scratchpad[0])/16.0; // get temperature (on < 16 precision the last bits are undefined, but that doesn't matter for the end result since the lower precision is still provided)
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}
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bool sensor_ds18b20_precision(uint64_t code, uint8_t precision)
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{
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if (precision<9 || precision>12) { // check input
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return false; // wrong precision value
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}
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if (0==code && !only) { // asked for broadcast but there are different slaves on bus
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return false; // broadcast not possible when there are also different slaves on bus
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}
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// send reset pulse
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if (!onewire_master_reset()) { // send reset to start communication
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return false; // no slave presence detected
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}
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// send ROM command to select slave(s)
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if (0==code) { // broadcast convert
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if (!onewire_master_rom_skip()) { // select all slaves
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return false; // ROM command failed
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}
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} else {
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if (!onewire_master_rom_match(code)) { // select specific slave
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return false; // ROM command failed
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}
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}
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// read scratchpad to get alarm values (on byte 2 and 3)
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uint8_t scratchpad[9] = {0}; // to store read scratchpad
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if (!onewire_master_function_read(0xbe, scratchpad, sizeof(scratchpad)*8)) { // read complete scratchpad
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return false; // error occurred during read
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}
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// verify if data is valid
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if (onewire_master_crc(scratchpad, sizeof(scratchpad))) { // check CRC checksum
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return false; // data corrupted
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}
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// send new configuration (and keep the alarm values)
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uint8_t configuration[3] = {0}; // to store T_HIGH, T_LOW, and configuration
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configuration[0] = scratchpad[2]; // keep T_HIGH
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configuration[1] = scratchpad[3]; // keep T_LOW
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configuration[2] = 0x1f+((precision-9)<<5); // set precision bit (R1-R0 on bit 6-5)
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if (!onewire_master_function_write(0x4e, configuration, sizeof(configuration)*8)) { // write scratchpad with new configuration (all three bytes must be written)
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return false; // error occurred during write
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}
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// store new configuration into sensor's EEPROM for retrieval on next power up
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if (!onewire_master_function_read(0x48, NULL, 0)) { // copy scratchpad (to EEPROM)
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return false; // error during copy
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}
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return true;
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}
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56
lib/sensor_ds18b20.h
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56
lib/sensor_ds18b20.h
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@ -0,0 +1,56 @@
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/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** library for Maxim DS18B20 digital temperature sensor (using 1-Wire protocol) (API)
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* @file sensor_ds18b20.h
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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* @note peripherals used: 1-Wire (timer @ref onewire_master_timer, GPIO @ref onewire_master_gpio)
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* @warning this library does not support parasite power mode and alarms
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*/
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#pragma once
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/** setup 1-Wire peripheral to communicate with sensors on bus */
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void sensor_ds18b20_setup(void);
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/** get number of DS18B20 sensors on bus
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* @return number of DS18B20 sensors on bus
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*/
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uint64_t sensor_ds18b20_number(void);
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/** verify if only DS18B20 sensors are on the bus
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* @return if only DS18B20 sensors are on the bus
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*/
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bool sensor_ds18b20_only(void);
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/** send all DS18B20 slaves on the bus
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* @param[out] code ROM code for sensor (0 if error occurred)
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* @return if an additional sensors have been detected
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*/
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bool sensor_ds18b20_list(uint64_t* code);
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/** start converting (e.g. measuring) temperature
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* @waning conversion time to wait before reading temperature depends on the resolution set (9 bits: 93.75ms, 10 bits: 187.5ms, 11 bits: 375ms, 12 bits: 950ms)
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* @param[in] code ROM code of sensor to start conversion on (0 for all, if only DS18B20 sensors are on the bus)
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* @return if conversion started
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*/
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bool sensor_ds18b20_convert(uint64_t code);
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/** get converted temperature
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* @note 85.0 C is the default temperature when no conversion has been performed
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* @param[in] code ROM code of sensor
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* @return temperature (NaN if error)
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*/
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float sensor_ds18b20_temperature(uint64_t code);
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/** set conversion precision
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* @param[in] code ROM code of sensor to start conversion on (0 for all, if only DS18B20 sensors are on the bus)
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* @param[in] precision precision in bits (9-12)
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* @return if operation succeeded
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*/
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bool sensor_ds18b20_precision(uint64_t code, uint8_t precision);
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