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Usermod Temperature: use full 12-bit precision #4916

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Usermod Temperature: use full 12-bit precision #4916

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fcc4632
Usermod Temperature: use full 12-bit precision
nename0 Sep 7, 2025
3017145
Temperature Usermod: fix DS1822 and DS18B20 family code
nename0 Sep 7, 2025
9056e5f
Add Dropdown to select 9 or 12 bit resolution
nename0 Sep 13, 2025
020fde9
Add 10 and 11 bit resolution, Correct rounding towards negativ inf
nename0 Sep 13, 2025
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31 changes: 22 additions & 9 deletions usermods/Temperature/Temperature.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -20,17 +20,19 @@ float UsermodTemperature::readDallas() {
}
#endif
switch(sensorFound) {
case 0x10: // DS18S20 has 9-bit precision
case 0x10: // DS18S20 has 9-bit precision - 1-bit fraction part
result = (data[1] << 8) | data[0];
retVal = float(result) * 0.5f;
break;
case 0x22: // DS18B20
case 0x28: // DS1822
case 0x22: // DS1822
case 0x28: // DS18B20
case 0x3B: // DS1825
case 0x42: // DS28EA00
result = (data[1]<<4) | (data[0]>>4); // we only need whole part, we will add fraction when returning
if (data[1] & 0x80) result |= 0xF000; // fix negative value
retVal = float(result) + ((data[0] & 0x08) ? 0.5f : 0.0f);
// 12-bit precision - 4-bit fraction part
result = (data[1] << 8) | data[0];
// Clear LSBs to match desired precision (9/10/11-bit) rounding towards negative infinity
result &= 0xFFFF << (3 - (resolution & 3));
retVal = float(result) * 0.0625f; // 2^(-4)
break;
}
}
Expand Down Expand Up @@ -69,8 +71,8 @@ bool UsermodTemperature::findSensor() {
if (oneWire->crc8(deviceAddress, 7) == deviceAddress[7]) {
switch (deviceAddress[0]) {
case 0x10: // DS18S20
case 0x22: // DS18B20
case 0x28: // DS1822
case 0x22: // DS1822
case 0x28: // DS18B20
case 0x3B: // DS1825
case 0x42: // DS28EA00
DEBUG_PRINTLN(F("Sensor found."));
Expand Down Expand Up @@ -277,6 +279,7 @@ void UsermodTemperature::addToConfig(JsonObject &root) {
top[FPSTR(_parasite)] = parasite;
top[FPSTR(_parasitePin)] = parasitePin;
top[FPSTR(_domoticzIDX)] = idx;
top[FPSTR(_resolution)] = resolution;
DEBUG_PRINTLN(F("Temperature config saved."));
}

Expand Down Expand Up @@ -304,6 +307,7 @@ bool UsermodTemperature::readFromConfig(JsonObject &root) {
parasite = top[FPSTR(_parasite)] | parasite;
parasitePin = top[FPSTR(_parasitePin)] | parasitePin;
idx = top[FPSTR(_domoticzIDX)] | idx;
resolution = top[FPSTR(_resolution)] | resolution;

if (!initDone) {
// first run: reading from cfg.json
Expand All @@ -324,14 +328,22 @@ bool UsermodTemperature::readFromConfig(JsonObject &root) {
}
}
// use "return !top["newestParameter"].isNull();" when updating Usermod with new features
return !top[FPSTR(_domoticzIDX)].isNull();
return !top[FPSTR(_resolution)].isNull();
}

void UsermodTemperature::appendConfigData() {
oappend(F("addInfo('")); oappend(String(FPSTR(_name)).c_str()); oappend(F(":")); oappend(String(FPSTR(_parasite)).c_str());
oappend(F("',1,'<i>(if no Vcc connected)</i>');")); // 0 is field type, 1 is actual field
oappend(F("addInfo('")); oappend(String(FPSTR(_name)).c_str()); oappend(F(":")); oappend(String(FPSTR(_parasitePin)).c_str());
oappend(F("',1,'<i>(for external MOSFET)</i>');")); // 0 is field type, 1 is actual field
oappend(F("dd=addDD('")); oappend(String(FPSTR(_name)).c_str());
oappend(F("','")); oappend(String(FPSTR(_resolution)).c_str()); oappend(F("');"));
oappend(F("addO(dd,'0.5 °C (9-bit)',0);"));
oappend(F("addO(dd,'0.25°C (10-bit)',1);"));
oappend(F("addO(dd,'0.125°C (11-bit)',2);"));
oappend(F("addO(dd,'0.0625°C (12-bit)',3);"));
oappend(F("addInfo('")); oappend(String(FPSTR(_name)).c_str()); oappend(F(":")); oappend(String(FPSTR(_resolution)).c_str());
oappend(F("',1,'<i>(ignored on DS18S20)</i>');")); // 0 is field type, 1 is actual field
}

float UsermodTemperature::getTemperature() {
Expand All @@ -351,6 +363,7 @@ const char UsermodTemperature::_readInterval[] PROGMEM = "read-interval-s";
const char UsermodTemperature::_parasite[] PROGMEM = "parasite-pwr";
const char UsermodTemperature::_parasitePin[] PROGMEM = "parasite-pwr-pin";
const char UsermodTemperature::_domoticzIDX[] PROGMEM = "domoticz-idx";
const char UsermodTemperature::_resolution[] PROGMEM = "resolution";
const char UsermodTemperature::_sensor[] PROGMEM = "sensor";
const char UsermodTemperature::_temperature[] PROGMEM = "temperature";
const char UsermodTemperature::_Temperature[] PROGMEM = "/temperature";
Expand Down
2 changes: 2 additions & 0 deletions usermods/Temperature/UsermodTemperature.h
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ class UsermodTemperature : public Usermod {

bool HApublished = false;
int16_t idx = -1; // Domoticz virtual sensor idx
uint8_t resolution = 0; // 9bits=0, 10bits=1, 11bits=2, 12bits=3

// strings to reduce flash memory usage (used more than twice)
static const char _name[];
Expand All @@ -56,6 +57,7 @@ class UsermodTemperature : public Usermod {
static const char _parasite[];
static const char _parasitePin[];
static const char _domoticzIDX[];
static const char _resolution[];
static const char _sensor[];
static const char _temperature[];
static const char _Temperature[];
Expand Down