//
//????FILE:?dht22.cpp
//?VERSION:?0.1.00
//?PURPOSE:?DHT22?Temperature?&?Humidity?Sensor?library?for?Arduino
//
//?DATASHEET:?
//
//?HISTORY:
//?0.1.0?by?Rob?Tillaart?（01/04/2011）
//?inspired?by?DHT11?library
//

#include?“dht.h“

#define?TIMEOUT?10000

/////////////////////////////////////////////////////
//
//?PUBLIC
//


//?return?values:
//??0?:?OK
//?-1?:?checksum?error
//?-2?:?timeout
int?dht::read11（uint8_t?pin）
{
	//?READ?VALUES
	int?rv?=?read（pin）;
	if?（rv?!=?0）?return?rv;

	//?CONVERT?AND?STORE
	humidity????=?bits[0];??//?bit[1]?==?0;
	temperature?=?bits[2];??//?bits[3]?==?0;

	//?TEST?CHECKSUM
	uint8_t?sum?=?bits[0]?+?bits[2];?//?bits[1]?&&?bits[3]?both?0
	if?（bits[4]?!=?sum）?return?-1;

	return?0;
}

//?return?values:
//??0?:?OK
//?-1?:?checksum?error
//?-2?:?timeout
int?dht::read22（uint8_t?pin）
{
	//?READ?VALUES
	int?rv?=?read（pin）;
	if?（rv?!=?0）?return?rv;

	//?CONVERT?AND?STORE
	humidity????=?word（bits[0]?bits[1]）?*?0.1;

	int?sign?=?1;
	if?（bits[2]?&?0x80）?//?negative?temperature
	{
		bits[2]?=?bits[2]?&?0x7F;
		sign?=?-1;
	}
	temperature?=?sign?*?word（bits[2]?bits[3]）?*?0.1;


	//?TEST?CHECKSUM
	uint8_t?sum?=?bits[0]?+?bits[1]?+?bits[2]?+?bits[3];
	if?（bits[4]?!=?sum）?return?-1;

	return?0;
}

/////////////////////////////////////////////////////
//
//?PRIVATE
//

//?return?values:
//??0?:?OK
//?-2?:?timeout
int?dht::read（uint8_t?pin）
{
	//?INIT?BUFFERVAR?TO?RECEIVE?DATA
	uint8_t?cnt?=?7;
	uint8_t?idx?=?0;

	//?EMPTY?BUFFER
	for?（int?i=0;?i
	//?REQUEST?SAMPLE
	pinMode（pin?OUTPUT）;
	digitalWrite（pin?LOW）;
	delay（20）;
	digitalWrite（pin?HIGH）;
	delayMicroseconds（40）;
	pinMode（pin?INPUT）;

	//?GET?ACKNOWLEDGE?or?TIMEOUT
	unsigned?int?loopCnt?=?TIMEOUT;
	while（digitalRead（pin）?==?LOW）
		if?（loopCnt--?==?0）?return?-2;

	loopCnt?=?TIMEOUT;
	while（digitalRead（pin）?==?HIGH）
		if?（loopCnt--?==?0）?return?-2;

	//?READ?THE?OUTPUT?-?40?BITS?=>?5?BYTES
	for?（int?i=0;?i<40;?i++）
	{
		loopCnt?=?TIMEOUT;
		while（digitalRead（pin）?==?LOW）
			if?（loopCnt--?==?0）?return?-2;

		unsigned?long?t?=?micros（）;

		loopCnt?=?TIMEOUT;
		while（digitalRead（pin）?==?HIGH）
			if?（loopCnt--?==?0）?return?-2;

		if?（（micros（）?-?t）?>?40）?bits[idx]?|=?（1?<		if?（cnt?==?0）???//?next?byte?
		{
			cnt?=?7;???
			idx++;??????
		}
		else?cnt--;
	}

	return?0;
}
//
//?END?OF?FILE
//

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2017-11-25?14:00??arduino-with-temperature-humidity-DHT11_DHT22-master\
?????文件????????1511??2017-11-25?14:00??arduino-with-temperature-humidity-DHT11_DHT22-master\DHT.zip
?????文件??????????87??2017-11-25?14:00??arduino-with-temperature-humidity-DHT11_DHT22-master\README.md
?????文件????????2467??2017-11-25?14:00??arduino-with-temperature-humidity-DHT11_DHT22-master\dht.cpp
?????文件?????????606??2017-11-25?14:00??arduino-with-temperature-humidity-DHT11_DHT22-master\dht.h
?????文件?????????349??2017-11-25?14:00??arduino-with-temperature-humidity-DHT11_DHT22-master\tempDHT11.ino