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278 lines
8.7 KiB
278 lines
8.7 KiB
// -----------------------------------------------------------------------------
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// Dallas OneWire Sensor
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// Uses OneWire library
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// Copyright (C) 2017 by Xose Pérez <xose dot perez at gmail dot com>
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// -----------------------------------------------------------------------------
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#pragma once
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#include "Arduino.h"
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#include "BaseSensor.h"
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#include <vector>
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#include <OneWire.h>
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#define DS_CHIP_DS18S20 0x10
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#define DS_CHIP_DS1822 0x22
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#define DS_CHIP_DS18B20 0x28
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#define DS_CHIP_DS1825 0x3B
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#define DS_PARASITE 1
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#define DS_DISCONNECTED -127
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#define DS_CMD_START_CONVERSION 0x44
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#define DS_CMD_READ_SCRATCHPAD 0xBE
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#define DS_ERROR_FAILED_RESET -2
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#define DS_ERROR_FAILED_READ -3
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class DallasSensor : public BaseSensor {
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public:
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// ---------------------------------------------------------------------
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// Public
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// ---------------------------------------------------------------------
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void setGPIO(unsigned char gpio) {
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if (_gpio == gpio) return;
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_gpio = gpio;
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_dirty = true;
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}
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// ---------------------------------------------------------------------
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unsigned char getGPIO() {
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return _gpio;
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}
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// ---------------------------------------------------------------------
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// Sensor API
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// ---------------------------------------------------------------------
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// Initialization method, must be idempotent
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void begin() {
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if (!_dirty) return;
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_dirty = false;
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_interval = SENSOR_READ_INTERVAL / 2;
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// OneWire
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if (_wire) delete _wire;
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_wire = new OneWire(_gpio);
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// Search devices
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loadDevices();
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// If no devices found check again pulling up the line
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if (_count == 0) {
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pinMode(_gpio, INPUT_PULLUP);
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loadDevices();
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}
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}
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// Loop-like method, call it in your main loop
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void tick() {
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static unsigned long last = 0;
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if (millis() - last < _interval) return;
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last = millis();
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// Every second we either start a conversion or read the scratchpad
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static bool conversion = true;
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if (conversion) {
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// Start conversion
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_wire->reset();
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_wire->skip();
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_wire->write(DS_CMD_START_CONVERSION, DS_PARASITE);
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} else {
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// Read scratchpads
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for (unsigned char index=0; index<_devices.size(); index++) {
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// Read scratchpad
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if (_wire->reset() == 0) {
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_error = DS_ERROR_FAILED_RESET;
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return;
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}
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_wire->select(_devices[index].address);
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_wire->write(DS_CMD_READ_SCRATCHPAD);
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uint8_t data[9];
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for (unsigned char i = 0; i < 9; i++) {
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data[i] = _wire->read();
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}
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#if false
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Serial.printf("[DS18B20] Data = ");
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for (unsigned char i = 0; i < 9; i++) {
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Serial.printf("%02X ", data[i]);
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}
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Serial.printf(" CRC = %02X\n", OneWire::crc8(data, 8));
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#endif
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if (_wire->reset() != 1) {
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_error = DS_ERROR_FAILED_READ;
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return;
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}
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if (OneWire::crc8(data, 8) != data[8]) {
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_error = SENSOR_ERROR_CRC;
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return;
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}
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memcpy(_devices[index].data, data, 9);
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}
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}
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conversion = !conversion;
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}
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// Descriptive name of the sensor
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String description() {
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char buffer[20];
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snprintf(buffer, sizeof(buffer), "Dallas @ GPIO%d", _gpio);
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return String(buffer);
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}
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// Descriptive name of the slot # index
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String slot(unsigned char index) {
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_error = SENSOR_ERROR_OK;
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if (index < _count) {
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char buffer[40];
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uint8_t * address = _devices[index].address;
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snprintf(buffer, sizeof(buffer), "%s (%02X%02X%02X%02X%02X%02X%02X%02X) @ GPIO%d",
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chipAsString(index).c_str(),
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address[0], address[1], address[2], address[3],
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address[4], address[5], address[6], address[7],
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_gpio
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);
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return String(buffer);
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}
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_error = SENSOR_ERROR_OUT_OF_RANGE;
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return String();
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}
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// Type for slot # index
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magnitude_t type(unsigned char index) {
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_error = SENSOR_ERROR_OK;
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if (index < _count) return MAGNITUDE_TEMPERATURE;
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_error = SENSOR_ERROR_OUT_OF_RANGE;
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return MAGNITUDE_NONE;
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}
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// Current value for slot # index
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double value(unsigned char index) {
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if (index >= _count) {
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_error = SENSOR_ERROR_OUT_OF_RANGE;
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return 0;
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}
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uint8_t * data = _devices[index].data;
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// Registers
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// byte 0: temperature LSB
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// byte 1: temperature MSB
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// byte 2: high alarm temp
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// byte 3: low alarm temp
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// byte 4: DS18S20: store for crc
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// DS18B20 & DS1822: configuration register
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// byte 5: internal use & crc
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// byte 6: DS18S20: COUNT_REMAIN
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// DS18B20 & DS1822: store for crc
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// byte 7: DS18S20: COUNT_PER_C
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// DS18B20 & DS1822: store for crc
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// byte 8: SCRATCHPAD_CRC
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int16_t raw = (data[1] << 8) | data[0];
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if (chip(index) == DS_CHIP_DS18S20) {
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raw = raw << 3; // 9 bit resolution default
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if (data[7] == 0x10) {
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raw = (raw & 0xFFF0) + 12 - data[6]; // "count remain" gives full 12 bit resolution
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}
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} else {
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byte cfg = (data[4] & 0x60);
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if (cfg == 0x00) raw = raw & ~7; // 9 bit res, 93.75 ms
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else if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms
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else if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms
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// 12 bit res, 750 ms
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}
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double value = (float) raw / 16.0;
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if (value == DS_DISCONNECTED) {
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_error = SENSOR_ERROR_CRC;
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return 0;
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}
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_error = SENSOR_ERROR_OK;
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return value;
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}
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protected:
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// ---------------------------------------------------------------------
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// Protected
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// ---------------------------------------------------------------------
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bool validateID(unsigned char id) {
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return (id == DS_CHIP_DS18S20) || (id == DS_CHIP_DS18B20) || (id == DS_CHIP_DS1822) || (id == DS_CHIP_DS1825);
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}
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unsigned char chip(unsigned char index) {
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if (index < _count) return _devices[index].address[0];
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return 0;
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}
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String chipAsString(unsigned char index) {
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unsigned char chip_id = chip(index);
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if (chip_id == DS_CHIP_DS18S20) return String("DS18S20");
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if (chip_id == DS_CHIP_DS18B20) return String("DS18B20");
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if (chip_id == DS_CHIP_DS1822) return String("DS1822");
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if (chip_id == DS_CHIP_DS1825) return String("DS1825");
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return String("Unknown");
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}
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void loadDevices() {
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uint8_t address[8];
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_wire->reset();
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_wire->reset_search();
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while (_wire->search(address)) {
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// Check CRC
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if (_wire->crc8(address, 7) == address[7]) {
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// Check ID
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if (validateID(address[0])) {
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ds_device_t device;
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memcpy(device.address, address, 8);
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_devices.push_back(device);
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}
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}
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}
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_count = _devices.size();
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}
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typedef struct {
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uint8_t address[8];
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uint8_t data[9];
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} ds_device_t;
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std::vector<ds_device_t> _devices;
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unsigned char _gpio;
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unsigned long _interval;
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OneWire * _wire;
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};
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