// -----------------------------------------------------------------------------
// Dallas OneWire Sensor
// Uses OneWire library
// Copyright (C) 2017-2018 by Xose Pérez <xose dot perez at gmail dot com>
// -----------------------------------------------------------------------------
#if SENSOR_SUPPORT && DALLAS_SUPPORT
#pragma once
#include "Arduino.h"
#include "BaseSensor.h"
#include <vector>
#include <OneWire.h>
#define DS_CHIP_DS18S20 0x10
#define DS_CHIP_DS1822 0x22
#define DS_CHIP_DS18B20 0x28
#define DS_CHIP_DS1825 0x3B
#define DS_DATA_SIZE 9
#define DS_PARASITE 1
#define DS_DISCONNECTED -127
#define DS_CMD_START_CONVERSION 0x44
#define DS_CMD_READ_SCRATCHPAD 0xBE
class DallasSensor : public BaseSensor {
public:
// ---------------------------------------------------------------------
// Public
// ---------------------------------------------------------------------
DallasSensor(): BaseSensor() {
_sensor_id = SENSOR_DALLAS_ID;
}
~DallasSensor() {
if (_wire) delete _wire;
if (_previous != GPIO_NONE) gpioReleaseLock(_previous);
}
// ---------------------------------------------------------------------
void setGPIO(unsigned char gpio) {
if (_gpio == gpio) return;
_gpio = gpio;
_dirty = true;
}
// ---------------------------------------------------------------------
unsigned char getGPIO() {
return _gpio;
}
// ---------------------------------------------------------------------
// Sensor API
// ---------------------------------------------------------------------
// Initialization method, must be idempotent
void begin() {
if (!_dirty) return;
// Manage GPIO lock
if (_previous != GPIO_NONE) gpioReleaseLock(_previous);
_previous = GPIO_NONE;
if (!gpioGetLock(_gpio)) {
_error = SENSOR_ERROR_GPIO_USED;
return;
}
// OneWire
if (_wire) delete _wire;
_wire = new OneWire(_gpio);
// Search devices
loadDevices();
// If no devices found check again pulling up the line
if (_count == 0) {
pinMode(_gpio, INPUT_PULLUP);
loadDevices();
}
// Check connection
if (_count == 0) {
gpioReleaseLock(_gpio);
} else {
_previous = _gpio;
}
_ready = true;
_dirty = false;
}
// Loop-like method, call it in your main loop
void tick() {
static unsigned long last = 0;
if (millis() - last < DALLAS_READ_INTERVAL) return;
last = millis();
// Every second we either start a conversion or read the scratchpad
static bool conversion = true;
if (conversion) {
// Start conversion
_wire->reset();
_wire->skip();
_wire->write(DS_CMD_START_CONVERSION, DS_PARASITE);
} else {
// Read scratchpads
for (unsigned char index=0; index<_devices.size(); index++) {
// Read scratchpad
if (_wire->reset() == 0) {
// Force a CRC check error
_devices[index].data[0] = _devices[index].data[0] + 1;
return;
}
_wire->select(_devices[index].address);
_wire->write(DS_CMD_READ_SCRATCHPAD);
uint8_t data[DS_DATA_SIZE];
for (unsigned char i = 0; i < DS_DATA_SIZE; i++) {
data[i] = _wire->read();
}
#if false
Serial.printf("[DS18B20] Data = ");
for (unsigned char i = 0; i < DS_DATA_SIZE; i++) {
Serial.printf("%02X ", data[i]);
}
Serial.printf(" CRC = %02X\n", OneWire::crc8(data, DS_DATA_SIZE-1));
#endif
if (_wire->reset() != 1) {
// Force a CRC check error
_devices[index].data[0] = _devices[index].data[0] + 1;
return;
}
memcpy(_devices[index].data, data, DS_DATA_SIZE);
}
}
conversion = !conversion;
}
// Descriptive name of the sensor
String description() {
char buffer[20];
snprintf(buffer, sizeof(buffer), "Dallas @ GPIO%d", _gpio);
return String(buffer);
}
// Address of the device
String address(unsigned char index) {
char buffer[20] = {0};
if (index < _count) {
uint8_t * address = _devices[index].address;
snprintf(buffer, sizeof(buffer), "%02X%02X%02X%02X%02X%02X%02X%02X",
address[0], address[1], address[2], address[3],
address[4], address[5], address[6], address[7]
);
}
return String(buffer);
}
// Descriptive name of the slot # index
String slot(unsigned char index) {
if (index < _count) {
char buffer[40];
uint8_t * address = _devices[index].address;
snprintf(buffer, sizeof(buffer), "%s (%02X%02X%02X%02X%02X%02X%02X%02X) @ GPIO%d",
chipAsString(index).c_str(),
address[0], address[1], address[2], address[3],
address[4], address[5], address[6], address[7],
_gpio
);
return String(buffer);
}
return String();
}
// Type for slot # index
unsigned char type(unsigned char index) {
if (index < _count) return MAGNITUDE_TEMPERATURE;
return MAGNITUDE_NONE;
}
// Pre-read hook (usually to populate registers with up-to-date data)
void pre() {
_error = SENSOR_ERROR_OK;
}
// Current value for slot # index
double value(unsigned char index) {
if (index >= _count) return 0;
uint8_t * data = _devices[index].data;
if (OneWire::crc8(data, DS_DATA_SIZE-1) != data[DS_DATA_SIZE-1]) {
_error = SENSOR_ERROR_CRC;
return 0;
}
// Registers
// byte 0: temperature LSB
// byte 1: temperature MSB
// byte 2: high alarm temp
// byte 3: low alarm temp
// byte 4: DS18S20: store for crc
// DS18B20 & DS1822: configuration register
// byte 5: internal use & crc
// byte 6: DS18S20: COUNT_REMAIN
// DS18B20 & DS1822: store for crc
// byte 7: DS18S20: COUNT_PER_C
// DS18B20 & DS1822: store for crc
// byte 8: SCRATCHPAD_CRC
int16_t raw = (data[1] << 8) | data[0];
if (chip(index) == DS_CHIP_DS18S20) {
raw = raw << 3; // 9 bit resolution default
if (data[7] == 0x10) {
raw = (raw & 0xFFF0) + 12 - data[6]; // "count remain" gives full 12 bit resolution
}
} else {
byte cfg = (data[4] & 0x60);
if (cfg == 0x00) raw = raw & ~7; // 9 bit res, 93.75 ms
else if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms
else if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms
// 12 bit res, 750 ms
}
double value = (float) raw / 16.0;
if (value == DS_DISCONNECTED) {
_error = SENSOR_ERROR_CRC;
return 0;
}
return value;
}
protected:
// ---------------------------------------------------------------------
// Protected
// ---------------------------------------------------------------------
bool validateID(unsigned char id) {
return (id == DS_CHIP_DS18S20) || (id == DS_CHIP_DS18B20) || (id == DS_CHIP_DS1822) || (id == DS_CHIP_DS1825);
}
unsigned char chip(unsigned char index) {
if (index < _count) return _devices[index].address[0];
return 0;
}
String chipAsString(unsigned char index) {
unsigned char chip_id = chip(index);
if (chip_id == DS_CHIP_DS18S20) return String("DS18S20");
if (chip_id == DS_CHIP_DS18B20) return String("DS18B20");
if (chip_id == DS_CHIP_DS1822) return String("DS1822");
if (chip_id == DS_CHIP_DS1825) return String("DS1825");
return String("Unknown");
}
void loadDevices() {
uint8_t address[8];
_wire->reset();
_wire->reset_search();
while (_wire->search(address)) {
// Check CRC
if (_wire->crc8(address, 7) == address[7]) {
// Check ID
if (validateID(address[0])) {
ds_device_t device;
memcpy(device.address, address, 8);
_devices.push_back(device);
}
}
}
_count = _devices.size();
}
typedef struct {
uint8_t address[8];
uint8_t data[DS_DATA_SIZE];
} ds_device_t;
std::vector<ds_device_t> _devices;
unsigned char _gpio = GPIO_NONE;
unsigned char _previous = GPIO_NONE;
OneWire * _wire = NULL;
};
#endif // SENSOR_SUPPORT && DALLAS_SUPPORT