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112 lines
1.9 KiB
C++
112 lines
1.9 KiB
C++
//
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// FILE: tinytinySHT2x.cpp
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// AUTHOR: Rob Tillaart, Viktor Balint
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// VERSION: 0.1.2
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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/tinytinySHT2x
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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()
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{
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}
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void tinySHT2x::begin(TwoWire *wire)
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{
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_wire = wire;
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_wire->begin();
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}
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float tinySHT2x::getTemperature()
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{
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uint8_t buffer[3];
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uint16_t raw;
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writeCmd(SHT2x_GET_TEMPERATURE_NO_HOLD);
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delay(70);
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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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float tinySHT2x::getHumidity()
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{
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uint8_t buffer[3];
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uint16_t raw;
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// HUMIDITY
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writeCmd(SHT2x_GET_HUMIDITY_NO_HOLD);
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delay(30);
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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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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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// 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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