mirror of
https://github.com/RobTillaart/Arduino.git
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149 lines
2.4 KiB
C++
149 lines
2.4 KiB
C++
//
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// FILE: tinySHT2x.cpp
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// AUTHOR: Rob Tillaart, Viktor Balint
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// VERSION: 0.2.0
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// DATE: 2021-09-27
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// PURPOSE: Arduino library for the SHT2x temperature and humidity sensor optimized for AVR tiny
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// URL: https://github.com/RobTillaart/tinySHT2x
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#include "tinySHT2x.h"
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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_ADDRESS 0x40
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tinySHT2x::tinySHT2x(TwoWire *wire)
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{
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_wire = wire;
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}
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bool tinySHT2x::begin()
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{
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return isConnected();
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}
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bool tinySHT2x::isConnected()
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{
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_wire->beginTransmission(SHT2x_ADDRESS);
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return (_wire->endTransmission() == 0);
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}
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bool tinySHT2x::reset()
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{
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return writeCmd(SHT2x_SOFT_RESET);
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}
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///////////////////////////////////
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//
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// ASYNC INTERFACE
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//
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void tinySHT2x::requestTemperature()
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{
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writeCmd(SHT2x_GET_TEMPERATURE_NO_HOLD);
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}
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float tinySHT2x::readTemperature()
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{
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uint8_t buffer[3];
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uint16_t raw;
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if (readBytes(3, (uint8_t*) &buffer[0], 90) == false)
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{
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return TINY_SHT2x_NO_VALUE;
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}
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raw = buffer[0] << 8;
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raw += buffer[1];
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raw &= 0xFFFC;
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return -46.85 + (175.72 / 65536.0) * raw;
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}
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void tinySHT2x::requestHumidity()
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{
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writeCmd(SHT2x_GET_HUMIDITY_NO_HOLD);
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}
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float tinySHT2x::readHumidity()
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{
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uint8_t buffer[3];
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uint16_t raw;
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if (readBytes(3, (uint8_t*) &buffer[0], 30) == false)
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{
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return TINY_SHT2x_NO_VALUE;
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}
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raw = buffer[0] << 8;
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raw += buffer[1];
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raw &= 0xFFFC;
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return -6.0 + (125.0 / 65536.0) * raw;
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}
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///////////////////////////////////
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//
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// SYNC INTERFACE
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//
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float tinySHT2x::getTemperature(uint8_t del)
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{
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requestTemperature();
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delay(del);
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return readTemperature();
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}
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float tinySHT2x::getHumidity(uint8_t del)
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{
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requestHumidity();
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delay(del);
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return readHumidity();
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}
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//////////////////////////////////////////////////////////
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//
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// PRIVATE
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//
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bool tinySHT2x::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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return (_wire->endTransmission() == 0);
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}
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bool tinySHT2x::readBytes(uint8_t n, uint8_t * val, uint8_t maxDuration)
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{
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_wire->requestFrom((uint8_t)SHT2x_ADDRESS, (uint8_t) n);
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uint32_t start = millis();
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while (_wire->available() < n)
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{
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if (millis() - start > maxDuration)
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{
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return false;
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}
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yield();
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}
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for (uint8_t i = 0; i < n; i++)
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{
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val[i] = _wire->read();
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}
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return true;
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}
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// -- END OF FILE --
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