xsns_05_ds18x20.ino

/*
  xsns_05_ds18x20.ino - DS18x20 temperature sensor support for Tasmota

  Copyright (C) 2019  Theo Arends

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#define USE_DS18x20
/*********************************************************************************************\
 * DS18B20 - Temperature - Multiple sensors
\*********************************************************************************************/

#define XSNS_05              5

//#define USE_DS18x20_RECONFIGURE    // When sensor is lost keep retrying or re-configure

#define DS18S20_CHIPID       0x10  // +/-0.5C 9-bit
#define DS1822_CHIPID        0x22  // +/-2C 12-bit
#define DS18B20_CHIPID       0x28  // +/-0.5C 12-bit
#define MAX31850_CHIPID      0x3B  // +/-0.25C 14-bit

#define W1_SKIP_ROM          0xCC
#define W1_CONVERT_TEMP      0x44
#define W1_WRITE_EEPROM      0x48
#define W1_WRITE_SCRATCHPAD  0x4E
#define W1_READ_SCRATCHPAD   0xBE

#define DS18X20_MAX_SENSORS  8

const char kDs18x20Types[] PROGMEM = "DS18x20|DS18S20|DS1822|DS18B20|MAX31850";

uint8_t ds18x20_chipids[] = { 0, DS18S20_CHIPID, DS1822_CHIPID, DS18B20_CHIPID, MAX31850_CHIPID };

struct DS18X20STRUCT {
  uint8_t address[8];
  uint8_t index;
  uint8_t valid;
  float   temperature;
} ds18x20_sensor[DS18X20_MAX_SENSORS];
uint8_t ds18x20_sensors = 0;
uint8_t ds18x20_pin = 0;
char ds18x20_types[12];
#ifdef W1_PARASITE_POWER
uint8_t ds18x20_sensor_curr = 0;
unsigned long w1_power_until = 0;
#endif

/*********************************************************************************************\
 * Embedded tuned OneWire library
\*********************************************************************************************/

#define W1_MATCH_ROM         0x55
#define W1_SEARCH_ROM        0xF0

uint8_t onewire_last_discrepancy = 0;
uint8_t onewire_last_family_discrepancy = 0;
bool onewire_last_device_flag = false;
unsigned char onewire_rom_id[8] = { 0 };

uint8_t OneWireReset(void)
{
  uint8_t retries = 125;

  //noInterrupts();
  pinMode(ds18x20_pin, Settings.flag3.ds18x20_internal_pullup ? INPUT_PULLUP : INPUT);  // SetOption74 - Enable internal pullup for single DS18x20 sensor
  do {
    if (--retries == 0) {
      return 0;
    }
    delayMicroseconds(2);
  } while (!digitalRead(ds18x20_pin));
  pinMode(ds18x20_pin, OUTPUT);
  digitalWrite(ds18x20_pin, LOW);
  delayMicroseconds(480);
  pinMode(ds18x20_pin, Settings.flag3.ds18x20_internal_pullup ? INPUT_PULLUP : INPUT);  // SetOption74 - Enable internal pullup for single DS18x20 sensor
  delayMicroseconds(70);
  uint8_t r = !digitalRead(ds18x20_pin);
  //interrupts();
  delayMicroseconds(410);
  return r;
}

void OneWireWriteBit(uint8_t v)
{
  static const uint8_t delay_low[2] = { 65, 10 };
  static const uint8_t delay_high[2] = { 5, 55 };

  v &= 1;
  //noInterrupts();
  digitalWrite(ds18x20_pin, LOW);
  pinMode(ds18x20_pin, OUTPUT);
  delayMicroseconds(delay_low[v]);
  digitalWrite(ds18x20_pin, HIGH);
  //interrupts();
  delayMicroseconds(delay_high[v]);
}

uint8_t OneWireReadBit(void)
{
  //noInterrupts();
  pinMode(ds18x20_pin, OUTPUT);
  digitalWrite(ds18x20_pin, LOW);
  delayMicroseconds(3);
  pinMode(ds18x20_pin, Settings.flag3.ds18x20_internal_pullup ? INPUT_PULLUP : INPUT);  // SetOption74 - Enable internal pullup for single DS18x20 sensor
  delayMicroseconds(10);
  uint8_t r = digitalRead(ds18x20_pin);
  //interrupts();
  delayMicroseconds(53);
  return r;
}

void OneWireWrite(uint8_t v)
{
  for (uint8_t bit_mask = 0x01; bit_mask; bit_mask <<= 1) {
    OneWireWriteBit((bit_mask & v) ? 1 : 0);
  }
}

uint8_t OneWireRead(void)
{
  uint8_t r = 0;

  for (uint8_t bit_mask = 0x01; bit_mask; bit_mask <<= 1) {
    if (OneWireReadBit()) {
      r |= bit_mask;
    }
  }
  return r;
}

void OneWireSelect(const uint8_t rom[8])
{
  OneWireWrite(W1_MATCH_ROM);
  for (uint32_t i = 0; i < 8; i++) {
    OneWireWrite(rom[i]);
  }
}

void OneWireResetSearch(void)
{
  onewire_last_discrepancy = 0;
  onewire_last_device_flag = false;
  onewire_last_family_discrepancy = 0;
  for (uint32_t i = 0; i < 8; i++) {
    onewire_rom_id[i] = 0;
  }
}

uint8_t OneWireSearch(uint8_t *newAddr)
{
  uint8_t id_bit_number = 1;
  uint8_t last_zero = 0;
  uint8_t rom_byte_number = 0;
  uint8_t search_result = 0;
  uint8_t id_bit;
  uint8_t cmp_id_bit;
  unsigned char rom_byte_mask = 1;
  unsigned char search_direction;

  if (!onewire_last_device_flag) {
    if (!OneWireReset()) {
      onewire_last_discrepancy = 0;
      onewire_last_device_flag = false;
      onewire_last_family_discrepancy = 0;
      return false;
    }
    OneWireWrite(W1_SEARCH_ROM);
    do {
      id_bit     = OneWireReadBit();
      cmp_id_bit = OneWireReadBit();

      if ((id_bit == 1) && (cmp_id_bit == 1)) {
        break;
      } else {
        if (id_bit != cmp_id_bit) {
          search_direction = id_bit;
        } else {
          if (id_bit_number < onewire_last_discrepancy) {
            search_direction = ((onewire_rom_id[rom_byte_number] & rom_byte_mask) > 0);
          } else {
            search_direction = (id_bit_number == onewire_last_discrepancy);
          }
          if (search_direction == 0) {
            last_zero = id_bit_number;
            if (last_zero < 9) {
              onewire_last_family_discrepancy = last_zero;
            }
          }
        }
        if (search_direction == 1) {
          onewire_rom_id[rom_byte_number] |= rom_byte_mask;
        } else {
          onewire_rom_id[rom_byte_number] &= ~rom_byte_mask;
        }
        OneWireWriteBit(search_direction);
        id_bit_number++;
        rom_byte_mask <<= 1;
        if (rom_byte_mask == 0) {
          rom_byte_number++;
          rom_byte_mask = 1;
        }
      }
    } while (rom_byte_number < 8);
    if (!(id_bit_number < 65)) {
      onewire_last_discrepancy = last_zero;
      if (onewire_last_discrepancy == 0) {
        onewire_last_device_flag = true;
      }
      search_result = true;
    }
  }
  if (!search_result || !onewire_rom_id[0]) {
    onewire_last_discrepancy = 0;
    onewire_last_device_flag = false;
    onewire_last_family_discrepancy = 0;
    search_result = false;
  }
  for (uint32_t i = 0; i < 8; i++) {
    newAddr[i] = onewire_rom_id[i];
  }
  return search_result;
}

bool OneWireCrc8(uint8_t *addr)
{
  uint8_t crc = 0;
  uint8_t len = 8;

  while (len--) {
    uint8_t inbyte = *addr++;          // from 0 to 7
    for (uint32_t i = 8; i; i--) {
      uint8_t mix = (crc ^ inbyte) & 0x01;
      crc >>= 1;
      if (mix) {
        crc ^= 0x8C;
      }
      inbyte >>= 1;
    }
  }
  return (crc == *addr);               // addr 8
}

/********************************************************************************************/

void Ds18x20Init(void)
{
  uint64_t ids[DS18X20_MAX_SENSORS];

  ds18x20_pin = pin[GPIO_DSB];

  OneWireResetSearch();

  ds18x20_sensors = 0;
  while (ds18x20_sensors < DS18X20_MAX_SENSORS) {
    if (!OneWireSearch(ds18x20_sensor[ds18x20_sensors].address)) {
      break;
    }
    if (OneWireCrc8(ds18x20_sensor[ds18x20_sensors].address) &&
       ((ds18x20_sensor[ds18x20_sensors].address[0] == DS18S20_CHIPID) ||
        (ds18x20_sensor[ds18x20_sensors].address[0] == DS1822_CHIPID) ||
        (ds18x20_sensor[ds18x20_sensors].address[0] == DS18B20_CHIPID) ||
        (ds18x20_sensor[ds18x20_sensors].address[0] == MAX31850_CHIPID))) {
      ds18x20_sensor[ds18x20_sensors].index = ds18x20_sensors;
      ids[ds18x20_sensors] = ds18x20_sensor[ds18x20_sensors].address[0];  // Chip id
      for (uint32_t j = 6; j > 0; j--) {
        ids[ds18x20_sensors] = ids[ds18x20_sensors] << 8 | ds18x20_sensor[ds18x20_sensors].address[j];
      }
      ds18x20_sensors++;
    }
  }
  for (uint32_t i = 0; i < ds18x20_sensors; i++) {
    for (uint32_t j = i + 1; j < ds18x20_sensors; j++) {
      if (ids[ds18x20_sensor[i].index] > ids[ds18x20_sensor[j].index]) {  // Sort ascending
        std::swap(ds18x20_sensor[i].index, ds18x20_sensor[j].index);
      }
    }
  }
  AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_DSB D_SENSORS_FOUND " %d"), ds18x20_sensors);
}

void Ds18x20Convert(void)
{
  OneWireReset();
#ifdef W1_PARASITE_POWER
  // With parasite power address one sensor at a time
  if (++ds18x20_sensor_curr >= ds18x20_sensors)
    ds18x20_sensor_curr = 0;
  OneWireSelect(ds18x20_sensor[ds18x20_sensor_curr].address);
#else
  OneWireWrite(W1_SKIP_ROM);           // Address all Sensors on Bus
#endif
  OneWireWrite(W1_CONVERT_TEMP);       // start conversion, no parasite power on at the end
//  delay(750);                          // 750ms should be enough for 12bit conv
}

bool Ds18x20Read(uint8_t sensor)
{
  uint8_t data[9];
  int8_t sign = 1;

  uint8_t index = ds18x20_sensor[sensor].index;
  if (ds18x20_sensor[index].valid) { ds18x20_sensor[index].valid--; }
  for (uint32_t retry = 0; retry < 3; retry++) {
    OneWireReset();
    OneWireSelect(ds18x20_sensor[index].address);
    OneWireWrite(W1_READ_SCRATCHPAD);
    for (uint32_t i = 0; i < 9; i++) {
      data[i] = OneWireRead();
    }
    if (OneWireCrc8(data)) {
      switch(ds18x20_sensor[index].address[0]) {
        case DS18S20_CHIPID: {
          if (data[1] > 0x80) {
            data[0] = (~data[0]) +1;
            sign = -1;                     // App-Note fix possible sign error
          }
          float temp9 = (float)(data[0] >> 1) * sign;
          ds18x20_sensor[index].temperature = ConvertTemp((temp9 - 0.25) + ((16.0 - data[6]) / 16.0));
          ds18x20_sensor[index].valid = SENSOR_MAX_MISS;
          return true;
        }
        case DS1822_CHIPID:
        case DS18B20_CHIPID: {
          if (data[4] != 0x7F) {
            data[4] = 0x7F;                 // Set resolution to 12-bit
            OneWireReset();
            OneWireSelect(ds18x20_sensor[index].address);
            OneWireWrite(W1_WRITE_SCRATCHPAD);
            OneWireWrite(data[2]);          // Th Register
            OneWireWrite(data[3]);          // Tl Register
            OneWireWrite(data[4]);          // Configuration Register
            OneWireSelect(ds18x20_sensor[index].address);
            OneWireWrite(W1_WRITE_EEPROM);  // Save scratchpad to EEPROM
#ifdef W1_PARASITE_POWER
            w1_power_until = millis() + 10; // 10ms specified duration for EEPROM write
#endif
          }
          uint16_t temp12 = (data[1] << 8) + data[0];
          if (temp12 > 2047) {
            temp12 = (~temp12) +1;
            sign = -1;
          }
          ds18x20_sensor[index].temperature = ConvertTemp(sign * temp12 * 0.0625);  // Divide by 16
          ds18x20_sensor[index].valid = SENSOR_MAX_MISS;
          return true;
        }
        case MAX31850_CHIPID: {
          int16_t temp14 = (data[1] << 8) + (data[0] & 0xFC);
          ds18x20_sensor[index].temperature = ConvertTemp(temp14 * 0.0625);  // Divide by 16
          ds18x20_sensor[index].valid = SENSOR_MAX_MISS;
          return true;
        }
      }
    }
  }
  AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DSB D_SENSOR_CRC_ERROR));
  return false;
}

void Ds18x20Name(uint8_t sensor)
{
  uint8_t index = sizeof(ds18x20_chipids);
  while (index) {
    if (ds18x20_sensor[ds18x20_sensor[sensor].index].address[0] == ds18x20_chipids[index]) {
      break;
    }
    index--;
  }
  GetTextIndexed(ds18x20_types, sizeof(ds18x20_types), index, kDs18x20Types);
  if (ds18x20_sensors > 1) {
    snprintf_P(ds18x20_types, sizeof(ds18x20_types), PSTR("%s%c%d"), ds18x20_types, IndexSeparator(), sensor +1);
  }
}

/********************************************************************************************/

void Ds18x20EverySecond(void)
{
#ifdef W1_PARASITE_POWER
  // skip access if there is still an eeprom write ongoing
  unsigned long now = millis();
  if (now < w1_power_until)
    return;
#endif
  if (uptime & 1
#ifdef W1_PARASITE_POWER
      // if more than 1 sensor and only parasite power: convert every cycle
      || ds18x20_sensors >= 2
#endif
  ) {
    // 2mS
    Ds18x20Convert();          // Start conversion, takes up to one second
  } else {
    for (uint32_t i = 0; i < ds18x20_sensors; i++) {
      // 12mS per device
      if (!Ds18x20Read(i)) {   // Read temperature
        Ds18x20Name(i);
        AddLogMissed(ds18x20_types, ds18x20_sensor[ds18x20_sensor[i].index].valid);
#ifdef USE_DS18x20_RECONFIGURE
        if (!ds18x20_sensor[ds18x20_sensor[i].index].valid) {
          memset(&ds18x20_sensor, 0, sizeof(ds18x20_sensor));
          Ds18x20Init();       // Re-configure
        }
#endif  // USE_DS18x20_RECONFIGURE
      }
    }
  }
}

void Ds18x20Show(bool json)
{
  for (uint32_t i = 0; i < ds18x20_sensors; i++) {
    uint8_t index = ds18x20_sensor[i].index;

    if (ds18x20_sensor[index].valid) {   // Check for valid temperature
      char temperature[33];
      dtostrfd(ds18x20_sensor[index].temperature, Settings.flag2.temperature_resolution, temperature);

      Ds18x20Name(i);

      if (json) {
        char address[17];
        for (uint32_t j = 0; j < 6; j++) {
          sprintf(address+2*j, "%02X", ds18x20_sensor[index].address[6-j]);  // Skip sensor type and crc
        }
        ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_ID "\":\"%s\",\"" D_JSON_TEMPERATURE "\":%s}"), ds18x20_types, address, temperature);
#ifdef USE_DOMOTICZ
        if ((0 == tele_period) && (0 == i)) {
          DomoticzSensor(DZ_TEMP, temperature);
        }
#endif  // USE_DOMOTICZ
#ifdef USE_KNX
        if ((0 == tele_period) && (0 == i)) {
          KnxSensor(KNX_TEMPERATURE, ds18x20_sensor[index].temperature);
        }
#endif  // USE_KNX
#ifdef USE_WEBSERVER
      } else {
        WSContentSend_PD(HTTP_SNS_TEMP, ds18x20_types, temperature, TempUnit());
#endif  // USE_WEBSERVER
      }
    }
  }
}

/*********************************************************************************************\
 * Interface
\*********************************************************************************************/

bool Xsns05(uint8_t function)
{
  bool result = false;

  if (pin[GPIO_DSB] < 99) {
    switch (function) {
      case FUNC_INIT:
        Ds18x20Init();
        break;
      case FUNC_EVERY_SECOND:
        Ds18x20EverySecond();
        break;
      case FUNC_JSON_APPEND:
        Ds18x20Show(1);
        break;
#ifdef USE_WEBSERVER
      case FUNC_WEB_SENSOR:
        Ds18x20Show(0);
        break;
#endif  // USE_WEBSERVER
    }
  }
  return result;
}

#endif  // USE_DS18x20