DHT11程序代碼.doc

/現(xiàn)象是循環(huán)顯示溫度和濕度各顯示三秒(小數(shù)位顯示0)/若需將dht11.c和其他的硬件結(jié)合使用,只需在需用到溫濕度值的文件加下面聲明/extern int wendu, shidu;(wendu是溫度值,shidu是濕度值,比實(shí)際的溫濕度值擴(kuò)大了十倍)/一、/文件名保存為main.c/*/除了dht11的接口外,其他的電路原理圖與天祥的C51板對(duì)應(yīng)/現(xiàn)象是循環(huán)顯示溫度和濕度各顯示三秒#include dht11.h#include sbit DULA = P26;/數(shù)碼管位定義sbit WELA = P27;static unsigned char flag;/中斷計(jì)數(shù)標(biāo)志static unsigned char code array= /數(shù)碼管編碼 0x3f,0x06,0x5b,0x4f,0x6, 0x6d,0x7d,0x07,0x7f,0x6f ;extern int wendu, shidu;static void InitTime(void);void Delay_1ms(unsigned int ms);static void SMG_Display(unsigned int value);int main(void) unsigned char mark = 0; /先等上電穩(wěn)定 Delay_1ms(1000); /因?yàn)樽x一次數(shù)據(jù)dht11才會(huì)觸發(fā)一次采集數(shù)據(jù). /即在先使用數(shù)據(jù)時(shí)采集一次數(shù)據(jù) ReadTempAndHumi(); /因?yàn)樵趦纱尾杉瘮?shù)據(jù)需一定的時(shí)間間隔,這里還可減少 Delay_1ms(3000); /設(shè)定定時(shí)器 InitTime(); while(1) /三秒讀一次溫濕度 if(flag = 60) flag = 0; mark+; /* /讀溫濕度,可檢測(cè)函數(shù)調(diào)用是否失敗, /函數(shù)返回OK(1)表示成功,返回EROR(0)表示失敗 /OK和EROR是在dht11.H中定義的宏 */ ReadTempAndHumi(); if(mark % 2 = 0) /顯示溫度 SMG_Display(wendu); else /顯示濕度 SMG_Display(shidu); return 0;/設(shè)定定時(shí)器static void InitTime(void) TH0 = (unsigned char)(65535 - 50000) 8); TL0 = (unsigned char)(65535 - 50000) ; TMOD = 0X01; TR0 = 1; ET0 = 1; EA = 1;/數(shù)碼管顯示函數(shù)static void SMG_Display(unsigned int value) unsigned char ge, bai, shi; ge = value % 10; shi = value % 100 / 10; bai = value % 1000 / 100; WELA = 1; P0 = 0XFE; WELA = 0; P0 = 0XFF; DULA = 1; P0 = arraybai; DULA = 0; Delay_1ms(2); WELA = 1; P0 = 0XFD; WELA = 0; P0 = 0XFF; DULA = 1; P0 = arrayshi; P0 |= 0x80; /*顯示小數(shù)點(diǎn)*/ DULA = 0; Delay_1ms(2); WELA = 1; P0 = 0XFB; WELA = 0; P0 = 0XFF; DULA = 1; P0 = arrayge; DULA = 0; Delay_1ms(2);/中斷函數(shù)void timer(void) interrupt 1 TH0 = (unsigned char)(65535 - 50000) 8); TL0 = (unsigned char)(65535 - 50000); flag+;/*/ 二、保存文件名dht11.h（保存時(shí)必須命名為dht11.h）/*/*/#ifndef _dht11_H_#define _HDT11_H_/設(shè)定標(biāo)志(static unsigned char status)的宏值#define OK 1#define EROR 0extern void Delay_1ms(unsigned int ms);/函數(shù)的返回值表示讀取數(shù)據(jù)是否成功 OK表示成功 EROR表示失敗extern unsigned char ReadTempAndHumi(void);#endif/*/*/三、保存的文件名是dht11.c/*/*/*/單片機(jī)時(shí)鐘為11.0592M#include dht11.h#include /請(qǐng)根據(jù)自己的dht11接的IO口來(lái)改動(dòng)位定義sbit dht11 = P20;/防止在與硬件通信時(shí)發(fā)生死循環(huán)的計(jì)數(shù)范圍#define NUMBER 20#define SIZE 5static unsigned char status;/存放五字節(jié)數(shù)據(jù)的數(shù)組static unsigned char value_arraySIZE;/*可在其他的文件引用溫濕度值,實(shí)際是溫度的整數(shù)的10倍如dht11讀回的溫度是26,則wendu = 260, 濕度同理*/int wendu, shidu;static unsigned char ReadValue(void);extern void Delay_1ms(unsigned int ms) unsigned int x, y; for(x = ms; x 0; x-) for(y = 124; y 0; y-); static void Delay_10us(void) unsigned char i; i-; i-; i-; i-; i-; i-;/*讀一個(gè)字節(jié)的數(shù)據(jù)*/static unsigned char ReadValue(void) unsigned char count, value = 0, i; status = OK; /設(shè)定標(biāo)志為正常狀態(tài) for(i = 8; i 0; i-) /高位在先 value = 1; count = 0; /每一位數(shù)據(jù)前會(huì)有一個(gè)50us的低電平時(shí)間.等待50us低電平結(jié)束 while(dht11 = 0 & count+ = NUMBER) status = EROR; /設(shè)定錯(cuò)誤標(biāo)志 return 0; /函數(shù)執(zhí)行過(guò)程發(fā)生錯(cuò)誤就退出函數(shù) /26-28us的高電平表示該位是0,為70us高電平表該位1 Delay_10us(); Delay_10us(); Delay_10us(); /延時(shí)30us后檢測(cè)數(shù)據(jù)線(xiàn)是否還是高電平 if(dht11 != 0) /進(jìn)入這里表示該位是1 value+; /等待剩余(約40us)的高電平結(jié)束 while(dht11 != 0 & count+ = NUMBER) status = EROR; /設(shè)定錯(cuò)誤標(biāo)志 return 0; return (value);/讀一次的數(shù)據(jù),共五字節(jié)extern unsigned char ReadTempAndHumi(void) unsigned char i = 0, check_value = 0,count = 0; EA = 0; dht11 = 0; /拉低數(shù)據(jù)線(xiàn)大于18ms發(fā)送開(kāi)始信號(hào) Delay_1ms(20); /需大于18毫秒 dht11 = 1; /釋放數(shù)據(jù)線(xiàn),用于檢測(cè)低電平的應(yīng)答信號(hào) /延時(shí)20-40us,等待一段時(shí)間后檢測(cè)應(yīng)答信號(hào),應(yīng)答信號(hào)是從機(jī)拉低數(shù)據(jù)線(xiàn)80us Delay_10us(); Delay_10us(); Delay_10us(); Delay_10us(); if(dht11 != 0) /檢測(cè)應(yīng)答信號(hào),應(yīng)答信號(hào)是低電平 /沒(méi)應(yīng)答信號(hào) EA = 1; return EROR; else /有應(yīng)答信號(hào) while(dht11 = 0 & count+ = NUMBER) /檢測(cè)計(jì)數(shù)器是否超過(guò)了設(shè)定的范圍 dht11 = 1; EA = 1; return EROR; /讀數(shù)據(jù)出錯(cuò),退出函數(shù) count = 0; dht11 = 1;/釋放數(shù)據(jù)線(xiàn) /應(yīng)答信號(hào)后會(huì)有一個(gè)80us的高電平，等待高電平結(jié)束 while(dht11 != 0 & count+ = NUMBER) dht11 = 1; EA = 1; return EROR; /退出函數(shù) /讀出濕.溫度值 for(i = 0; i SIZE; i+) value_arayi = ReadValue(); if(status = EROR)/調(diào)用ReadValue()讀數(shù)據(jù)出錯(cuò)會(huì)設(shè)定status為EROR dht11 = 1; EA = 1; return EROR; /讀出的最后一個(gè)值是校驗(yàn)值不需加上去 if(i != SIZE - 1) /讀出的五字節(jié)數(shù)據(jù)中的前四字節(jié)數(shù)據(jù)和等于第五字節(jié)數(shù)據(jù)表示成功 check_value += value_arayi; /end for /在沒(méi)用發(fā)生函數(shù)調(diào)用失敗時(shí)進(jìn)行校驗(yàn)