//
//????FILE:?dht11.cpp
//?VERSION:?0.4.1
//?PURPOSE:?DHT11?Temperature?&?Humidity?Sensor?library?for?Arduino
//?LICENSE:?GPL?v3?（http://www.gnu.org/licenses/gpl.html）
//
//?DATASHEET:?http://www.micro4you.com/files/sensor/DHT11.pdf
//
//?HISTORY:
//?George?Hadjikyriacou?-?Original?version?（??）
//?Mod?by?SimKard?-?Version?0.2?（24/11/2010）
//?Mod?by?Rob?Tillaart?-?Version?0.3?（28/03/2011）
//?+?added?comments
//?+?removed?all?non?DHT11?specific?code
//?+?added?references
//?Mod?by?Rob?Tillaart?-?Version?0.4?（17/03/2012）
//?+?added?1.0?support
//?Mod?by?Rob?Tillaart?-?Version?0.4.1?（19/05/2012）
//?+?added?error?codes
//

#include?“dht11.h“

//?Return?values:
//?DHTLIB_OK
//?DHTLIB_ERROR_CHECKSUM
//?DHTLIB_ERROR_TIMEOUT
int?dht11::read（int?pin）
{
	//?BUFFER?TO?RECEIVE
	uint8_t?bits[5];
	uint8_t?cnt?=?7;
	uint8_t?idx?=?0;

	//?EMPTY?BUFFER
	for?（int?i=0;?i
	//?REQUEST?SAMPLE
	pinMode（pin?OUTPUT）;
	digitalWrite（pin?LOW）;
	delay（18）;
	digitalWrite（pin?HIGH）;
	delayMicroseconds（40）;
	pinMode（pin?INPUT）;

	//?ACKNOWLEDGE?or?TIMEOUT
	unsigned?int?loopCnt?=?10000;
	while（digitalRead（pin）?==?LOW）
		if?（loopCnt--?==?0）?return?DHTLIB_ERROR_TIMEOUT;

	loopCnt?=?10000;
	while（digitalRead（pin）?==?HIGH）
		if?（loopCnt--?==?0）?return?DHTLIB_ERROR_TIMEOUT;

	//?READ?OUTPUT?-?40?BITS?=>?5?BYTES?or?TIMEOUT
	for?（int?i=0;?i<40;?i++）
	{
		loopCnt?=?10000;
		while（digitalRead（pin）?==?LOW）
			if?（loopCnt--?==?0）?return?DHTLIB_ERROR_TIMEOUT;

		unsigned?long?t?=?micros（）;

		loopCnt?=?10000;
		while（digitalRead（pin）?==?HIGH）
			if?（loopCnt--?==?0）?return?DHTLIB_ERROR_TIMEOUT;

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

	//?WRITE?TO?RIGHT?VARS
????????//?as?bits[1]?and?bits[3]?are?allways?zero?they?are?omitted?in?formulas.
	humidity????=?bits[0];?
	temperature?=?bits[2];?

	uint8_t?sum?=?bits[0]?+?bits[2];??

	if?（bits[4]?!=?sum）?return?DHTLIB_ERROR_CHECKSUM;
	return?DHTLIB_OK;
}
//
//?END?OF?FILE
//

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2014-01-15?18:15??Dht11\
?????文件????????2149??2012-09-04?14:09??Dht11\dht11.cpp
?????文件?????????392??2012-09-04?14:38??Dht11\dht11.h
?????目錄???????????0??2014-01-15?18:15??Dht11\examples\
?????目錄???????????0??2014-01-15?18:15??Dht11\examples\dht11\
?????文件????????2474??2012-09-05?10:41??Dht11\examples\dht11\dht11.ino
?????文件????????1331??2019-02-14?14:20??DHT11例程.ino