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140 lines
2.7 KiB
C
140 lines
2.7 KiB
C
/**
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******************************************************************************
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* @file DHT11.c
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* @author Eshen Wang
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* @version V1.0.0
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* @date 1-May-2015
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* @brief DHT11 temperature and humidity sensor driver.
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******************************************************************************
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* UNPUBLISHED PROPRIETARY SOURCE CODE
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* Copyright (c) 2016 MXCHIP Inc.
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*
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* The contents of this file may not be disclosed to third parties, copied or
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* duplicated in any form, in whole or in part, without the prior written
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* permission of MXCHIP Corporation.
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******************************************************************************
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*/
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#include "mico.h"
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#include "DHT11.h"
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/*------------------------------ delay function ------------------------------*/
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void Delay_us(uint32_t nus)
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{
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MicoNanosendDelay( 1000*nus );
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}
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void Delay_ms(uint16_t nms)
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{
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mico_thread_msleep(nms);
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}
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/*--------------------------------- DHT11 Operations -------------------------*/
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//Reset DHT11
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void DHT11_Rst(void)
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{
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DHT11_IO_OUT(); //SET OUTPUT
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DHT11_DATA_Clr(); //GPIOA.0=0
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Delay_ms(20); //Pull down Least 18ms
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DHT11_DATA_Set(); //GPIOA.0=1
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Delay_us(30); //Pull up 20~40us
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}
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uint8_t DHT11_Check(void)
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{
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uint8_t retry=0;
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DHT11_IO_IN(); //SET INPUT
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while (DHT11_DQ_IN&&retry<100) //DHT11 Pull down 40~80us
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{
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retry++;
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Delay_us(1);
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}
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if(retry>=100)
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return 1;
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else
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retry=0;
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while (!DHT11_DQ_IN&&retry<100) //DHT11 Pull up 40~80us
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{
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retry++;
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Delay_us(1);
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}
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if(retry>=100)
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return 1; //chack error
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return 0;
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}
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uint8_t DHT11_Read_Bit(void)
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{
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uint8_t retry=0;
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while(DHT11_DQ_IN&&retry<100) //wait become Low level
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{
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retry++;
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Delay_us(1);
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}
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retry=0;
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while(!DHT11_DQ_IN&&retry<100) //wait become High level
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{
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retry++;
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Delay_us(1);
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}
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Delay_us(40);//wait 40us
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if(DHT11_DQ_IN)
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return 1;
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else
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return 0;
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}
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uint8_t DHT11_Read_Byte(void)
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{
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uint8_t i,dat;
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dat=0;
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for (i=0;i<8;i++)
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{
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dat<<=1;
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dat|=DHT11_Read_Bit();
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}
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return dat;
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}
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uint8_t DHT11_Read_Data(uint8_t *temperature,uint8_t *humidity)
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{
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uint8_t buf[5];
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uint8_t i;
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DHT11_Rst();
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if(DHT11_Check()==0)
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{
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for(i=0;i<5;i++)
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{
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buf[i]=DHT11_Read_Byte();
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}
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if((buf[0]+buf[1]+buf[2]+buf[3])==buf[4])
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{
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*humidity=buf[0];
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*temperature=buf[2];
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}
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}
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else {
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return 1;
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}
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return 0;
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}
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uint8_t DHT11_Init(void)
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{
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DHT11_IO_OUT();
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DHT11_Rst();
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return DHT11_Check();
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}
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