DHT22 temperature and humidity sensor

Driver for the DHT22 temperature and humidity sensor. More...

Files
file	dht22.c
	Driver for the DHT22 temperature and humidity sensor.
file	dht22.h
	Header file for the DHT22 temperature and humidity sensor.

DHT22 auxiliary functions
int16_t	dht22_read_all (int16_t *temperature, int16_t *humidity)

DHT22 default pin and port
#define	DHT22_PIN   5
#define	DHT22_PORT   GPIO_A_NUM

DHT22 available commands
#define	DHT22_READ_TEMP   0x01
#define	DHT22_READ_HUM   0x02
#define	DHT22_READ_ALL   0x03

DHT22 return types
#define	DHT22_ERROR   (-1)
#define	DHT22_SUCCESS   0x00
#define	DHT22_BUSY   0xFF

DHT22 constants
#define	DHT22_BUFFER   5
	Buffer to store the samples
#define	DHT22_COUNT   8
	Minimum ticks to detect a "1" bit
#define	DHT22_MAX_TIMMING   85
	Maximum ticks in a single operation.
#define	DHT22_READING_DELAY   1
	1 us
#define	DHT22_READY_TIME   40
	40 us
#define	DHT22_START_TIME   (RTIMER_SECOND / 50)
	20 ms
#define	DHT22_AWAKE_TIME   (RTIMER_SECOND / 4)
	250 ms

Detailed Description

Driver for the DHT22 temperature and humidity sensor.