68 lines
2.5 KiB
C
68 lines
2.5 KiB
C
/*
|
|
DHT-11 Library
|
|
(c) Created by Charalampos Andrianakis on 18/12/11.
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated documentation files (the "Software"), to deal
|
|
in the Software without restriction, including without limitation the rights
|
|
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
copies of the Software, and to permit persons to whom the Software is
|
|
furnished to do so, subject to the following conditions:
|
|
|
|
The above copyright notice and this permission notice shall be included in
|
|
all copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
THE SOFTWARE.
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <avr/io.h>
|
|
#include <util/delay.h>
|
|
|
|
/* DHT 1-wire is at PortE.6 */
|
|
#define DHT_PIN_READ PINE
|
|
#define DHT_PIN_MASK _BV(PE6)
|
|
#define DHT_PxOUT PORTE
|
|
#define DHT_PxDIR DDRE
|
|
|
|
#define SET_PIN_INPUT() (DHT_PxDIR &= ~DHT_PIN_MASK)
|
|
#define SET_PIN_OUTPUT() (DHT_PxDIR |= DHT_PIN_MASK)
|
|
|
|
#define OUTP_0() (DHT_PxOUT &= ~DHT_PIN_MASK)
|
|
#define OUTP_1() (DHT_PxOUT |= DHT_PIN_MASK)
|
|
|
|
#define PIN_INIT() do{ \
|
|
SET_PIN_INPUT(); \
|
|
OUTP_0(); \
|
|
} while(0)
|
|
|
|
|
|
/* Drive the one wire interface hight */
|
|
#define DHT_DRIVE() do { \
|
|
SET_PIN_OUTPUT(); \
|
|
OUTP_1(); \
|
|
} while (0)
|
|
|
|
/* Release the one wire by turning on the internal pull-up. */
|
|
#define DHT_RELEASE() do { \
|
|
SET_PIN_INPUT(); \
|
|
OUTP_1(); \
|
|
} while (0)
|
|
|
|
/* Read one bit. */
|
|
#define DHT_INP() (DHT_PIN_READ & DHT_PIN_MASK)
|
|
|
|
//The packet size is 40bit but each bit consists of low and high state
|
|
//so 40 x 2 = 80 transitions. Also we have 2 transistions DHT response
|
|
//and 2 transitions which indicates End Of Frame. In total 84
|
|
#define MAXTIMINGS 84
|
|
|
|
//This is the main function which requests and reads the packet
|
|
uint8_t DHT_Read_Data(uint16_t *temperature, uint16_t *humidity);
|