mirror of
https://github.com/RobTillaart/Arduino.git
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681 lines
12 KiB
C++
681 lines
12 KiB
C++
//
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// FILE: SHT2x.cpp
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// AUTHOR: Rob Tillaart, Viktor Balint
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// VERSION: 0.4.0
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// DATE: 2021-09-25
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// PURPOSE: Arduino library for the SHT2x temperature and humidity sensor
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// URL: https://github.com/RobTillaart/SHT2x
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#include "SHT2x.h"
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// SUPPORTED COMMANDS
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#define SHT2x_GET_TEMPERATURE_NO_HOLD 0xF3
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#define SHT2x_GET_HUMIDITY_NO_HOLD 0xF5
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#define SHT2x_SOFT_RESET 0xFE
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#define SHT2x_WRITE_USER_REGISTER 0xE6
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#define SHT2x_READ_USER_REGISTER 0xE7
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#define SHT2x_HEATER_TIMEOUT 180000UL // milliseconds
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#define SHT2x_ADDRESS 0x40
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#define SHT2x_USRREG_RESOLUTION 0x81
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#define SHT2x_USRREG_BATTERY 0x20
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#define SHT2x_USRREG_HEATER 0x04
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//////////////////////////////////////////////////////////////
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//
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// PUBLIC
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//
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SHT2x::SHT2x(TwoWire *wire)
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{
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_wire = wire;
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_lastRead = 0;
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_lastRequest = 0;
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_requestType = SHT2x_REQ_NONE;
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_rawTemperature = 0;
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_rawHumidity = 0;
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_heatTimeout = 0;
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_heaterStart = 0;
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_heaterStop = 0;
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_heaterOn = false;
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_error = SHT2x_OK;
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_status = 0;
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_resolution = 0;
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}
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#if defined(ESP8266) || defined(ESP32)
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bool SHT2x::begin(const int dataPin, const int clockPin)
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{
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if ((dataPin < 255) && (clockPin < 255))
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{
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_wire->begin(dataPin, clockPin);
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} else {
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_wire->begin();
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}
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return reset();
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}
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#endif
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bool SHT2x::begin()
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{
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_wire->begin();
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return reset();
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}
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bool SHT2x::isConnected()
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{
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_wire->beginTransmission(SHT2x_ADDRESS);
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int rv = _wire->endTransmission();
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if (rv != 0) _error = SHT2x_ERR_NOT_CONNECT;
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return (rv == 0);
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}
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/////////////////////////////////////////////////////////
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//
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// SYNCHRONOUS INTERFACE
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//
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bool SHT2x::read()
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{
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// TEMPERATURE
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if (requestTemperature() == false) return false;
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while (reqTempReady() == false)
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{
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yield();
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};
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if (readTemperature() == false) return false;
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// HUMIDITY
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if (requestHumidity() == false) return false;
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while (reqHumReady() == false)
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{
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yield();
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};
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if (readHumidity() == false) return false;
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return true;
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}
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/////////////////////////////////////////////////////////
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//
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// ASYNCHRONOUS INTERFACE
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//
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bool SHT2x::requestTemperature()
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{
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writeCmd(SHT2x_GET_TEMPERATURE_NO_HOLD);
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_lastRequest = millis();
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_requestType = SHT2x_REQ_TEMPERATURE;
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return true;
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}
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bool SHT2x::requestHumidity()
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{
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writeCmd(SHT2x_GET_HUMIDITY_NO_HOLD);
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_lastRequest = millis();
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_requestType = SHT2x_REQ_HUMIDITY;
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return true;
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}
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bool SHT2x::reqTempReady()
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{
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if (_requestType != SHT2x_REQ_TEMPERATURE) return false;
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uint32_t waiting = millis() - _lastRequest;
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// table 7
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if (waiting < 11) return false;
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if (_resolution == 3) return true;
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if (waiting < 22) return false;
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if (_resolution == 1) return true;
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if (waiting < 43) return false;
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if (_resolution == 2) return true;
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if (waiting < 85) return false;
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return true;
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}
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bool SHT2x::reqHumReady()
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{
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if (_requestType != SHT2x_REQ_HUMIDITY) return false;
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uint32_t waiting = millis() - _lastRequest;
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// table 7
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if (waiting < 4) return false;
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if (_resolution == 1) return true; // 8 bit
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if (waiting < 9) return false;
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if (_resolution == 2) return true; // 10 bit
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if (waiting < 15) return false;
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if (_resolution == 3) return true; // 11 bit
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if (waiting < 29) return false;
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return true; // 12 bit
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}
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bool SHT2x::requestReady()
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{
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return (reqTempReady() || reqHumReady());
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}
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bool SHT2x::readTemperature()
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{
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uint8_t buffer[3];
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if (readBytes(3, (uint8_t*) &buffer[0], 90) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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if (crc8(buffer, 2) != buffer[2])
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{
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_error = SHT2x_ERR_CRC_TEMP;
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// return false; // do not fail yet
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}
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_rawTemperature = buffer[0] << 8;
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_rawTemperature += buffer[1];
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_rawTemperature &= 0xFFFC;
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// clear requestType
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_requestType = SHT2x_REQ_NONE;
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_status = buffer[1] & 0x0003;
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if (_status == 0xFF) // TODO != 0x01 (need HW to test)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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return true;
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}
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bool SHT2x::readHumidity()
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{
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uint8_t buffer[3];
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if (readBytes(3, (uint8_t*) &buffer[0], 30) == false)
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{
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return false;
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}
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if (crc8(buffer, 2) != buffer[2])
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{
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_error = SHT2x_ERR_CRC_HUM;
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// return false; // do not fail yet
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}
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_rawHumidity = buffer[0] << 8;
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_rawHumidity += buffer[1];
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_rawHumidity &= 0xFFFC; // TODO is this mask OK? as humidity is max 12 bit..
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// clear requestType
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_requestType = SHT2x_REQ_NONE;
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_status = buffer[1] & 0x0003;
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if (_status == 0xFF) // TODO != 0x02 (need HW to test)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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_error = SHT2x_OK;
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_lastRead = millis();
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return true;
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}
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uint32_t SHT2x::lastRequest()
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{
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return _lastRequest;
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}
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uint8_t SHT2x::getRequestType()
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{
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return _requestType;
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}
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/////////////////////////////////////////////////////////
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//
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// TEMPERATURE AND HUMIDTY
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//
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float SHT2x::getTemperature()
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{
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// par 6.2
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return -46.85 + (175.72 / 65536.0) * _rawTemperature;
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}
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float SHT2x::getHumidity()
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{
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// par 6.1
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return -6.0 + (125.0 / 65536.0) * _rawHumidity;
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}
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uint16_t SHT2x::getRawTemperature()
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{
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return _rawTemperature;
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}
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uint16_t SHT2x::getRawHumidity()
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{
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return _rawHumidity;
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}
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bool SHT2x::reset()
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{
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bool b = writeCmd(SHT2x_SOFT_RESET);
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return b;
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}
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uint8_t SHT2x::getStatus()
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{
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return _status;
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}
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uint32_t SHT2x::lastRead()
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{
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return _lastRead;
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}
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/////////////////////////////////////////////////////////
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//
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// HEATER
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//
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void SHT2x::setHeatTimeout(uint8_t seconds)
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{
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_heatTimeout = seconds;
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if (_heatTimeout > 180) _heatTimeout = 180;
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}
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uint8_t SHT2x::getHeatTimeout()
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{
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return _heatTimeout;
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}
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bool SHT2x::heatOn()
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{
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if (isHeaterOn()) return true;
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if ((_heaterStop > 0) && (millis() - _heaterStop < SHT2x_HEATER_TIMEOUT))
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{
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_error = SHT2x_ERR_HEATER_COOLDOWN;
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return false;
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}
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uint8_t userReg = 0x00;
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writeCmd(SHT2x_READ_USER_REGISTER);
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if (readBytes(1, (uint8_t *) &userReg, 5) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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// HEAT BIT ON
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userReg |= SHT2x_USRREG_HEATER;
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if (writeCmd(SHT2x_WRITE_USER_REGISTER, userReg) == false)
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{
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_error = SHT2x_ERR_HEATER_ON;
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return false;
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}
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_heaterStart = millis();
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_heaterOn = true;
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return true;
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}
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bool SHT2x::heatOff()
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{
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uint8_t userReg = 0x00;
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writeCmd(SHT2x_READ_USER_REGISTER);
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if (readBytes(1, (uint8_t *) &userReg, 5) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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// HEAT BIT OFF
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userReg &= ~SHT2x_USRREG_HEATER;
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if (writeCmd(SHT2x_WRITE_USER_REGISTER, userReg) == false)
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{
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_error = SHT2x_ERR_HEATER_OFF; // can be serious!
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return false;
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}
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_heaterStop = millis();
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_heaterOn = false;
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return true;
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}
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bool SHT2x::isHeaterOn()
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{
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if (_heaterOn == false)
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{
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return false;
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}
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// did not exceed time out
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if (millis() - _heaterStart < (_heatTimeout * 1000UL))
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{
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return true;
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}
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heatOff();
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return false;
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}
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bool SHT2x::setHeaterLevel(uint8_t level)
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{
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if (level > 15)
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{
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return false;
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}
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uint8_t heaterReg = 0;
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writeCmd(0x11); // Read Heater Control Register
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if (readBytes(1, (uint8_t *) &heaterReg, 5) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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heaterReg &= 0xF0;
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heaterReg |= level;
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if (writeCmd(0x51, heaterReg) == false)
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{
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_error = -1;
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return false;
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}
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return true;
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}
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bool SHT2x::getHeaterLevel(uint8_t & level)
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{
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uint8_t heaterReg = 0;
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writeCmd(0x11); // Read Heater Control Register
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if (readBytes(1, (uint8_t *) &heaterReg, 5) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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level = heaterReg & 0x0F;
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return true;
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}
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int SHT2x::getError()
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{
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int rv = _error;
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_error = SHT2x_OK;
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return rv;
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}
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/////////////////////////////////////////////////////////
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//
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// Electronic Identification Code
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//
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// Sensirion_Humidity_SHT2x_Electronic_Identification_Code_V1.1.pdf
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uint32_t SHT2x::getEIDA()
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{
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uint32_t id = 0;
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uint8_t buffer[8];
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writeCmd(0xFA, 0x0F);
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if (readBytes(8, (uint8_t *) buffer, 10) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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// skip CRC's
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for (uint8_t i = 0; i < 4; i++)
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{
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id <<= 8;
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id |= buffer[i*2];
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}
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return id;
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}
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// Sensirion_Humidity_SHT2x_Electronic_Identification_Code_V1.1.pdf
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uint32_t SHT2x::getEIDB()
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{
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uint32_t id = 0;
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uint8_t buffer[8];
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writeCmd(0xFC, 0xC9);
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if (readBytes(8, (uint8_t *) buffer, 10) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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// skip CRC's
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id = buffer[0]; // SNC_1
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id <<= 8;
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id |= buffer[1]; // SNC_0
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id <<= 8;
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id |= buffer[3]; // SNA_1
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id <<= 8;
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id |= buffer[4]; // SNA_0
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return id;
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}
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uint8_t SHT2x::getFirmwareVersion()
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{
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uint8_t version = 0;
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writeCmd(0x84, 0xB8);
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if (readBytes(1, (uint8_t *) &version, 10) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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return version;
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}
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/////////////////////////////////////////////////////////
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//
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// RESOLUTION
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//
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bool SHT2x::setResolution(uint8_t res)
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{
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if (res > 3) return false;
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uint8_t userReg = 0x00;
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writeCmd(SHT2x_READ_USER_REGISTER);
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if (readBytes(1, (uint8_t *) &userReg, 5) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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// clear old resolution and set new
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userReg &= ~SHT2x_USRREG_RESOLUTION;
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// resolution is bit 7 and bit 0.
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userReg |= ((res & 0x02) << 6);
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userReg |= (res & 0x01);
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if (writeCmd(SHT2x_WRITE_USER_REGISTER, userReg) == false)
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{
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_error = SHT2x_ERR_RESOLUTION;
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return false;
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}
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_resolution = res;
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return true;
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}
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uint8_t SHT2x::getResolution()
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{
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return _resolution;
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};
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/////////////////////////////////////////////////////////
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//
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// OTHER
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//
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bool SHT2x::batteryOK()
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{
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uint8_t userReg = 0x00;
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writeCmd(SHT2x_READ_USER_REGISTER);
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if (readBytes(1, (uint8_t *) &userReg, 5) == false)
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{
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_error = SHT2x_ERR_READBYTES;
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return false;
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}
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return (userReg & SHT2x_USRREG_BATTERY) == 0;
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}
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//////////////////////////////////////////////////////////
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//
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// PROTECTED
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//
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uint8_t SHT2x::crc8(const uint8_t *data, uint8_t len)
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{
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// CRC-8 formula from page 14 of SHT spec pdf
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// Sensirion_Humidity_Sensors_SHT2x_CRC_Calculation.pdf
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const uint8_t POLY = 0x31;
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uint8_t crc = 0x00;
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for (uint8_t j = len; j; --j)
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{
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crc ^= *data++;
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for (uint8_t i = 8; i; --i)
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{
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crc = (crc & 0x80) ? (crc << 1) ^ POLY : (crc << 1);
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}
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}
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return crc;
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}
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bool SHT2x::writeCmd(uint8_t cmd)
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{
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_wire->beginTransmission(SHT2x_ADDRESS);
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_wire->write(cmd);
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if (_wire->endTransmission() != 0)
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{
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_error = SHT2x_ERR_WRITECMD;
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return false;
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}
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return true;
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}
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bool SHT2x::writeCmd(uint8_t cmd, uint8_t value)
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{
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_wire->beginTransmission(SHT2x_ADDRESS);
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_wire->write(cmd);
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_wire->write(value);
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if (_wire->endTransmission() != 0)
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{
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_error = SHT2x_ERR_WRITECMD;
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return false;
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}
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return true;
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}
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bool SHT2x::readBytes(uint8_t n, uint8_t *val, uint8_t maxDuration)
|
|
{
|
|
_wire->requestFrom((uint8_t)SHT2x_ADDRESS, (uint8_t) n);
|
|
uint32_t start = millis();
|
|
while (_wire->available() < n)
|
|
{
|
|
if (millis() - start > maxDuration)
|
|
{
|
|
_error = SHT2x_ERR_READBYTES;
|
|
return false;
|
|
}
|
|
yield();
|
|
}
|
|
|
|
for (uint8_t i = 0; i < n; i++)
|
|
{
|
|
val[i] = _wire->read();
|
|
}
|
|
_error = SHT2x_OK;
|
|
return true;
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////
|
|
//
|
|
// DERIVED SHT
|
|
//
|
|
SHT20::SHT20(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
SHT21::SHT21(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
SHT25::SHT25(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////
|
|
//
|
|
// DERIVED HTU
|
|
//
|
|
HTU20::HTU20(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
HTU21::HTU21(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////
|
|
//
|
|
// DERIVED Si70xx
|
|
//
|
|
Si7013::Si7013(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
Si7020::Si7020(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
Si7021::Si7021(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////
|
|
//
|
|
// DERIVED Si70xx
|
|
//
|
|
GY21::GY21(TwoWire *wire) : SHT2x(wire)
|
|
{
|
|
}
|
|
|
|
|
|
// -- END OF FILE --
|
|
|