Tasmota/sonoff/xsns_ds18x20.ino

/*
Copyright (c) 2017 Theo Arends.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

- Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/

#ifdef USE_DS18x20
/*********************************************************************************************\
 * DS18B20 - Temperature
\*********************************************************************************************/

#define DS18S20_CHIPID       0x10
#define DS18B20_CHIPID       0x28
#define MAX31850_CHIPID      0x3B

#define W1_SKIP_ROM          0xCC
#define W1_CONVERT_TEMP      0x44
#define W1_READ_SCRATCHPAD   0xBE

#define DS18X20_MAX_SENSORS  8

#include <OneWire.h>

OneWire *ds = NULL;

uint8_t ds18x20_addr[DS18X20_MAX_SENSORS][8];
uint8_t ds18x20_idx[DS18X20_MAX_SENSORS];
uint8_t ds18x20_snsrs = 0;
char dsbstype[9];

void ds18x20_init()
{
  ds = new OneWire(pin[GPIO_DSB]);
}

void ds18x20_search()
{
  uint8_t num_sensors=0;
  uint8_t sensor = 0;
  uint8_t i;

  ds->reset_search();
  for (num_sensors = 0; num_sensors < DS18X20_MAX_SENSORS; num_sensors) {
    if (!ds->search(ds18x20_addr[num_sensors])) {
      ds->reset_search();
      break;
    }
    // If CRC Ok and Type DS18S20, DS18B20 or MAX31850
    if ((OneWire::crc8(ds18x20_addr[num_sensors], 7) == ds18x20_addr[num_sensors][7]) &&
       ((ds18x20_addr[num_sensors][0]==DS18S20_CHIPID) || (ds18x20_addr[num_sensors][0]==DS18B20_CHIPID) || (ds18x20_addr[num_sensors][0]==MAX31850_CHIPID))) {
      num_sensors++;
    }
  }
  for (int i = 0; i < num_sensors; i++) {
    ds18x20_idx[i] = i;
  }
  for (int i = 0; i < num_sensors; i++) {
    for (int j = i + 1; j < num_sensors; j++) {
      if (uint32_t(ds18x20_addr[ds18x20_idx[i]]) > uint32_t(ds18x20_addr[ds18x20_idx[j]])) {
        std::swap(ds18x20_idx[i], ds18x20_idx[j]);
      }
    }
  }
  ds18x20_snsrs = num_sensors;
}

uint8_t ds18x20_sensors()
{
  return ds18x20_snsrs;
}

String ds18x20_address(uint8_t sensor)
{
  char addrStr[20];
  uint8_t i;

  for (i = 0; i < 8; i++) {
    sprintf(addrStr+2*i, "%02X", ds18x20_addr[ds18x20_idx[sensor]][i]);
  }
  return String(addrStr);
}

void ds18x20_convert()
{
  ds->reset();
  ds->write(W1_SKIP_ROM);        // Address all Sensors on Bus
  ds->write(W1_CONVERT_TEMP);    // start conversion, no parasite power on at the end
//  delay(750);                   // 750ms should be enough for 12bit conv
}

boolean ds18x20_read(uint8_t sensor, float &t)
{
  byte data[12];
  int8_t sign = 1;
  uint8_t i = 0;
  float temp9 = 0.0;
  uint8_t present = 0;

  t = NAN;

  ds->reset();
  ds->select(ds18x20_addr[ds18x20_idx[sensor]]);
  ds->write(W1_READ_SCRATCHPAD); // Read Scratchpad

  for (i = 0; i < 9; i++) {
    data[i] = ds->read();
  }
  if (OneWire::crc8(data, 8) == data[8]) {
    switch(ds18x20_addr[ds18x20_idx[sensor]][0]) {
    case DS18S20_CHIPID:  // DS18S20
/*
//    App_note AN162.pdf page 9
      int temp_lsb, temp_msb;
      temp_msb = data[1];                             // Sign byte + lsbit
      temp_lsb = data[0];                             // Temp data plus lsb
      if (temp_msb <= 0x80) temp_lsb = (temp_lsb/2);  // Shift to get whole degree
      temp_msb = temp_msb & 0x80;                     // Mask all but the sign bit
      if (temp_msb >= 0x80) {                         // Negative temperature
        temp_lsb = (~temp_lsb)+1;                     // Twos complement
        temp_lsb = (temp_lsb/2);                      // Shift to get whole degree
        temp_lsb = ((-1)*temp_lsb);                   // Add sign bit
      }
      t = (int)temp_lsb;                              // Temperature in whole degree
*/
      if (data[1] > 0x80) {
        data[0] = (~data[0]) +1;
        sign = -1;  // App-Note fix possible sign error
      }
      if (data[0] & 1) {
        temp9 = ((data[0] >> 1) + 0.5) * sign;
      } else {
        temp9 = (data[0] >> 1) * sign;
      }
      t = convertTemp((temp9 - 0.25) + ((16.0 - data[6]) / 16.0));
      break;
    case DS18B20_CHIPID:   // DS18B20
    case MAX31850_CHIPID:  // MAX31850
      uint16_t temp12 = (data[1] << 8) + data[0];
      if (temp12 > 2047) {
        temp12 = (~temp12) +1;
        sign = -1;
      }
      t = convertTemp(sign * temp12 * 0.0625);
      break;
    }
  }
  return (!isnan(t));
}

/*********************************************************************************************\
 * Presentation
\*********************************************************************************************/

void ds18x20_type(uint8_t sensor)
{
  strcpy_P(dsbstype, PSTR("DS18x20"));
  switch(ds18x20_addr[ds18x20_idx[sensor]][0]) {
  case DS18S20_CHIPID:
    strcpy_P(dsbstype, PSTR("DS18S20"));
    break;
  case DS18B20_CHIPID:
    strcpy_P(dsbstype, PSTR("DS18B20"));
    break;
  case MAX31850_CHIPID:
    strcpy_P(dsbstype, PSTR("MAX31850"));
    break;
  }
}

void ds18x20_mqttPresent(char* svalue, uint16_t ssvalue, uint8_t* djson)
{
  char stemp1[10];
  char stemp2[10];
  float t;

  byte dsxflg = 0;
  for (byte i = 0; i < ds18x20_sensors(); i++) {
    if (ds18x20_read(i, t)) {           // Check if read failed
      ds18x20_type(i);
      dtostrf(t, 1, sysCfg.flag.temperature_resolution, stemp2);
      if (!dsxflg) {
        snprintf_P(svalue, ssvalue, PSTR("%s, \"DS18x20\":{"), svalue);
        *djson = 1;
        stemp1[0] = '\0';
      }
      dsxflg++;
      snprintf_P(svalue, ssvalue, PSTR("%s%s\"DS%d\":{\"Type\":\"%s\", \"Address\":\"%s\", \"Temperature\":%s}"),
        svalue, stemp1, i +1, dsbstype, ds18x20_address(i).c_str(), stemp2);
      strcpy(stemp1, ", ");
#ifdef USE_DOMOTICZ
      if (dsxflg == 1) domoticz_sensor1(stemp2);
#endif  // USE_DOMOTICZ
    }
  }
  if (dsxflg) {
    snprintf_P(svalue, ssvalue, PSTR("%s}"), svalue);
  }
}

#ifdef USE_WEBSERVER
String ds18x20_webPresent()
{
  String page = "";
  char stemp[10];
  char stemp2[16];
  char sensor[80];
  float t;

  for (byte i = 0; i < ds18x20_sensors(); i++) {
    if (ds18x20_read(i, t)) {   // Check if read failed
      ds18x20_type(i);
      dtostrf(t, 1, sysCfg.flag.temperature_resolution, stemp);
      snprintf_P(stemp2, sizeof(stemp2), PSTR("%s-%d"), dsbstype, i +1);
      snprintf_P(sensor, sizeof(sensor), HTTP_SNS_TEMP, stemp2, stemp, tempUnit());
      page += sensor;
    }
  }
  ds18x20_search();      // Check for changes in sensors number
  ds18x20_convert();     // Start Conversion, takes up to one second
  return page;
}
#endif  // USE_WEBSERVER
#endif  // USE_DS18x20