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