mirror of https://github.com/arendst/Tasmota.git
137 lines
3.8 KiB
C++
137 lines
3.8 KiB
C++
/*
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xns_74_lmt01.ino - Support for single wire LMT01 Temperature Sensor
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Copyright (C) 2021 Theo Arends, Justifiably
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifdef USE_LMT01
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/*********************************************************************************************\
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* LMT01 - 0.5°C Accurate 2-Pin Digital Output Temperature Sensor With Pulse Count Interface
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*
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* Uses fragments of public domain code LMT01_Example.ino released by Texas Instruments, July 10th 2017.
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* See https://training.ti.com/how-interface-lmt01-temperature-sensor-arduino
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\*********************************************************************************************/
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#define XSNS_74 74
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#define LMT01_TIMEOUT 200 // ms timeout for a reading cycle
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bool lmt01_initialized = false;
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float lmt01_temperature = NAN;
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volatile int lmt01_pulseCount = 0;
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static void IRAM_ATTR LMT01_countPulse(void) {
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lmt01_pulseCount++;
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}
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void LMT01_Init(void) {
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if (PinUsed(GPIO_LMT01)) {
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pinMode(Pin(GPIO_LMT01), INPUT);
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attachInterrupt(Pin(GPIO_LMT01), LMT01_countPulse, FALLING);
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lmt01_initialized = true;
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}
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}
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void LMT01_GetTemperature(void) {
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int pulses = 0;
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pulses = LMT01_getPulses();
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if (pulses >= 0) {
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// simple linear conversion, datasheet has a look-up table alternative
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// which is accurate over a wider temperature range
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lmt01_temperature = ConvertTemp(0.0625 * pulses - 50);
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} else {
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lmt01_temperature = NAN; // Timeout
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}
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}
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int LMT01_getPulses(void) {
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int timeout = LMT01_TIMEOUT;
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int hold = -1;
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// complete current pulse cycle (50ms max)
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while(lmt01_pulseCount != hold && --timeout > 0) {
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hold = lmt01_pulseCount;
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delay(1);
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}
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lmt01_pulseCount = 0;
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// wait for start of next (54ms max)
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while(lmt01_pulseCount == 0 && --timeout > 0) {
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delay(1);
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}
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hold = -1;
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// take this count (up to 50ms)
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while(lmt01_pulseCount != hold && --timeout > 0) {
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hold = lmt01_pulseCount;
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delay(1);
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}
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// discard spurious low counts
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if (timeout > 0 && hold >= 10) {
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return hold;
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}
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return -1;
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}
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void LMT01_Show(bool Json) {
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if (Json) {
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ResponseAppend_P(JSON_SNS_F_TEMP, "LMT01", Settings->flag2.temperature_resolution, &lmt01_temperature);
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#ifdef USE_DOMOTICZ
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if (0 == TasmotaGlobal.tele_period) {
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DomoticzFloatSensor(DZ_TEMP, lmt01_temperature);
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}
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#endif // USE_DOMOTICZ
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#ifdef USE_KNX
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if (0 == TasmotaGlobal.tele_period) {
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KnxSensor(KNX_TEMPERATURE, lmt01_temperature);
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}
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#endif // USE_KNX
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#ifdef USE_WEBSERVER
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} else {
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WSContentSend_Temp("LMT01", lmt01_temperature);
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#endif // USE_WEBSERVER
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}
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}
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/*********************************************************************************************\
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* Interface
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\*********************************************************************************************/
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bool Xsns74(uint32_t function)
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{
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bool result = false;
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if (FUNC_INIT == function) {
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LMT01_Init();
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}
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else if (lmt01_initialized) {
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switch (function) {
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case FUNC_EVERY_SECOND:
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LMT01_GetTemperature();
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break;
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case FUNC_JSON_APPEND:
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LMT01_Show(true);
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break;
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#ifdef USE_WEBSERVER
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case FUNC_WEB_SENSOR:
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LMT01_Show(false);
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break;
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#endif // USE_WEBSERVER
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}
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}
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return result;
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}
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#endif // USE_LMT01
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