GY-63_MS5611/libraries/DHT2pin/dht2pin.cpp
2022-11-01 20:26:33 +01:00

152 lines
3.3 KiB
C++

//
// FILE: DHT2pin.cpp
// AUTHOR: Rob Tillaart
// VERSION: 0.1.3
// PURPOSE: Experimental DHT Temperature & Humidity Sensor library for Arduino
// URL: https://github.com/RobTillaart/DHT2pin
// http://arduino.cc/playground/Main/DHTLib
//
// HISTORY: see changelog.md
#include "DHT2pin.h"
/////////////////////////////////////////////////////
//
// PUBLIC
//
// return values:
// DHTLIB_OK
// DHTLIB_ERROR_CHECKSUM
// DHTLIB_ERROR_TIMEOUT
int DHT2pin::read11()
{
// READ VALUES
int rv = _readSensor(DHTLIB_DHT11_WAKEUP);
if (rv != DHTLIB_OK)
{
humidity = DHTLIB_INVALID_VALUE; // invalid value, or is NaN prefered?
temperature = DHTLIB_INVALID_VALUE; // invalid value
return rv;
}
// CONVERT AND STORE
humidity = bits[0]; // bits[1] == 0;
temperature = bits[2]; // bits[3] == 0;
// TEST CHECKSUM
// bits[1] && bits[3] both 0
uint8_t sum = bits[0] + bits[2];
if (bits[4] != sum) return DHTLIB_ERROR_CHECKSUM;
return DHTLIB_OK;
}
// return values:
// DHTLIB_OK
// DHTLIB_ERROR_CHECKSUM
// DHTLIB_ERROR_TIMEOUT
int DHT2pin::read()
{
// READ VALUES
int rv = _readSensor(DHTLIB_DHT_WAKEUP);
if (rv != DHTLIB_OK)
{
humidity = DHTLIB_INVALID_VALUE; // invalid value, or is NaN prefered?
temperature = DHTLIB_INVALID_VALUE; // invalid value
return rv; // propagate error value
}
// CONVERT AND STORE
humidity = word(bits[0], bits[1]) * 0.1;
temperature = word(bits[2] & 0x7F, bits[3]) * 0.1;
if (bits[2] & 0x80) // negative temperature
{
temperature = -temperature;
}
// TEST CHECKSUM
uint8_t sum = bits[0] + bits[1] + bits[2] + bits[3];
if (bits[4] != sum)
{
return DHTLIB_ERROR_CHECKSUM;
}
return DHTLIB_OK;
}
/////////////////////////////////////////////////////
//
// PRIVATE
//
// return values:
// DHTLIB_OK
// DHTLIB_ERROR_TIMEOUT
int DHT2pin::_readSensor(uint8_t wakeupDelay)
{
// INIT BUFFERVAR TO RECEIVE DATA
uint8_t mask = 128;
uint8_t idx = 0;
// EMPTY BUFFER
for (uint8_t i = 0; i < 5; i++) bits[i] = 0;
// REQUEST SAMPLE
digitalWrite(_wpin, LOW);
delay(wakeupDelay);
digitalWrite(_wpin, HIGH);
delayMicroseconds(40);
// GET ACKNOWLEDGE or TIMEOUT
uint16_t loopCnt = DHTLIB_TIMEOUT;
while(digitalRead(_rpin) == LOW)
{
if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
}
loopCnt = DHTLIB_TIMEOUT;
while(digitalRead(_rpin) == HIGH)
{
if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
}
// READ THE OUTPUT - 40 BITS => 5 BYTES
for (uint8_t i = 40; i != 0; i--)
{
loopCnt = DHTLIB_TIMEOUT;
while(digitalRead(_rpin) == LOW)
{
if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
}
uint32_t t = micros();
loopCnt = DHTLIB_TIMEOUT;
while(digitalRead(_rpin) == HIGH)
{
if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
}
if ((micros() - t) > 40)
{
bits[idx] |= mask;
}
mask >>= 1;
if (mask == 0) // next byte?
{
mask = 128;
idx++;
}
}
digitalWrite(_wpin, HIGH);
return DHTLIB_OK;
}
// -- END OF FILE --