공지사항
제휴안내
쇼핑안내
판매순위
장바구니 메인 
전체상품 목록
온라인 입금계좌
|
|
hst11_at89s53.c.zip
SHT11_150px_shot.jpg
sensorSHT11.htm
SHT11 습도센서 8051 인터페이스
 상대습도 센서 SHT11는 첫번째 디지털 습도와 온도센서이다. SHT11 디지털 습도와 온도 센서는 충분히 교정었으며 장기간 안정도와 매우 저렴한 가격으로 사용하기 쉽다. 디지털 CMOSens 기술은 하나의 칩위에 2개의 센서와 읽기 출력회로로 직접된다. . CMOSens 기술은 센서, 증폭기, 보정 메모리 상수 값, A/D 컨버터 그리고 디지털 인터페이스가 단일 silicon chip 위에 구현된 제품으로 표현 될 수 있다. .SHT11 (14bit ADC for Temperature, 12bit ADC for Humidity) Temperature(Tc) = -39.60 + 0.01*adc_value humidity = -4 + 0.0405 * adc_value + (-2.8*10^-6)*(adc_value^2) Humidity_true = (Tc -25) * (0.01+0.00008*adc_value) + humidity // ● 습도 계산 루틴. // calculates temperature [ C] and humidity [%RH] // 입력 : humi [Ticks] (12 bit), temp [Ticks] (14 bit) // 출력 : humi [%RH], temp [ C] void calc_sth11(float *p_humidity ,float *p_temperature) { const float C1=-4.0; // for 12 Bit const float C2= 0.0405; // for 12 Bit const float C3=-0.0000028; // for 12 Bit const float T1=0.01; // for 14 Bit @ 5V const float T2=0.00008; // for 14 Bit @ 5V float rh=*p_humidity; // rh: Humidity [Ticks] 12 Bit float t=*p_temperature; // t: Temperature [Ticks] 14 Bit float rh_lin; // rh_lin: Humidity linear float rh_true; // rh_true: Temperature compensated humidity float t_C; // t_C : Temperature [ C] t_C=t*0.01 ? 40; //calc. Temperature from ticks to [ C] rh_lin=C3*rh*rh + C2*rh + C1; //calc. Humidity from ticks to [%RH] rh_true=(t_C-25)*(T1+T2*rh)+rh_lin; //calc. Temperature compensated humidity [%RH] if(rh_true>100)rh_true=100; //cut if the value is outside of if(rh_true<0.1)rh_true=0.1; //the physical possible range *p_temperature=t_C; //return temperature [ C] *p_humidity=rh_true; //return humidity[%RH] } // ● 이슬점의 계산 루틴 입력 : humidity [%RH], temperature [ C] 출력 : output: dew point [ C] float calc_dewpoint(float h,float t) { float k,dew_point ; k = (log10(h)-2)/0.4343 + (17.62*t)/(243.12+t); dew_point = 243.12*k/(17.62-k); return dew_point; } ● SHTxx 습도와 온도 센서 송신용 소스코드 이 용응자료는 다음의 목적을 위한 MPU용 C코드의 예를 제공한다. 기본 오류처리로 SHTxx의 습도 (RH) 혹은 온도 (T) 의 읽기 RH 직선화와 온도보상의 계산 status register의 호출 RH 와 T 를 위한 이슬점 계산 UART 처리 (좋은 데이터를 PC로 전송하는 방법) . ● 8051 MPU 펌웨어용 KEIL C 소스 (통신속도는 11.0592MHz Xtal에서 9600 BPS 이다) //*********************************************************************** // 프로젝트 : SHT11 평기 프로그램 (V2.0) // 파일 이름 : SHT11.c // MPU : 80C51 시리즈 (AT89S53을 사용 그러나 다른 8051로 변경이 가능) // 번역기 : Keil Version 6.14 // 저자 : MST (c) Sensirion AG //*********************************************************************** #include <AT89s53.h> //Microcontroller specific library, e.g. port definitions #include <intrins.h> //Keil library (is used for _nop()_ operation) #include <math.h> //Keil library #include <stdio.h> //Keil library // typedef union { unsigned int i; float f; } value; // //*********************************************************************** // modul-var //*********************************************************************** enum {TEMP,HUMI}; #define DATA P1_1 #define SCK P1_0 #define noACK 0 #define ACK 1 //adr command r/w #define STATUS_REG_W 0x06 //000 0011 0 #define STATUS_REG_R 0x07 //000 0011 1 #define MEASURE_TEMP 0x03 //000 0001 1 #define MEASURE_HUMI 0x05 //000 0010 1 #define RESET 0x1e //000 1111 0 // //*********************************************************************** char s_write_byte(unsigned char value) //*********************************************************************** // writes a byte on the Sensibus and checks the acknowledge { unsigned char i,error=0; for (i=0x80;i>0;i/=2) //shift bit for masking { if (i & value) DATA=1; //masking value with i , write to SENSI-BUS else DATA=0; SCK=1; //clk for SENSI-BUS _nop_();_nop_();_nop_(); //pulswith approx. 5 us SCK=0; } DATA=1; //release DATA-line SCK=1; //clk #9 for ack error=DATA; //check ack (DATA will be pulled down by SHT11) SCK=0; return error; //error=1 in case of no acknowledge } // //*********************************************************************** // char s_read_byte(unsigned char ack) //*********************************************************************** // reads a byte form the Sensibus and gives an acknowledge in case of "ack=1" char s_read_byte(unsigned char ack) { unsigned char i,val=0; DATA=1; //release DATA-line for (i=0x80;i>0;i/=2) //shift bit for masking { SCK=1; //clk for SENSI-BUS if (DATA) val=(val | i); //read bit SCK=0; } DATA=!ack; //in case of "ack==1" pull down DATA-Line SCK=1; //clk #9 for ack _nop_();_nop_();_nop_(); //pulswith approx. 5 us SCK=0; DATA=1; //release DATA-line return val; } // //*********************************************************************** // void s_transstart(void) //*********************************************************************** // generates a transmission start // _____ ________ // DATA: |_______| // ___ ___ // SCK : ___| |___| |______ void s_transstart(void) { DATA=1; SCK=0; //Initial state _nop_(); SCK=1; _nop_(); DATA=0; _nop_(); SCK=0; _nop_();_nop_();_nop_(); SCK=1; _nop_(); DATA=1; _nop_(); SCK=0; } // //*********************************************************************** // void s_connectionreset(void) //*********************************************************************** // communication reset: DATA-line=1 and at least 9 SCK cycles followed by transstart // DATA: ------------------------____------ // SCK : __-_-_-_-_-_-_-_-_-__--__--____ void s_connectionreset(void) { unsigned char i; DATA=1; SCK=0; //Initial state for(i=0;i<9;i++) //9 SCK cycles { SCK=1; SCK=0; } s_transstart(); //transmission start } // //*********************************************************************** // char s_softreset(void) //*********************************************************************** // resets the sensor by a softreset char s_softreset(void) { unsigned char error=0; s_connectionreset(); //reset communication error+=s_write_byte(RESET); //send RESET-command to sensor return error; //error=1 in case of no response form the sensor } // //*********************************************************************** // char s_read_statusreg(unsigned char *p_value, unsigned char *p_checksum) //*********************************************************************** // reads the status register with checksum (8-bit) char s_read_statusreg(unsigned char *p_value, unsigned char *p_checksum) { unsigned char error=0; s_transstart(); //transmission start error=s_write_byte(STATUS_REG_R); //send command to sensor *p_value=s_read_byte(ACK); //read status register (8-bit) *p_checksum=s_read_byte(noACK); //read checksum (8-bit) return error; //error=1 in case of no response form the sensor } // //*********************************************************************** // char s_write_statusreg(unsigned char *p_value) //*********************************************************************** // writes the status register with checksum (8-bit) char s_write_statusreg(unsigned char *p_value) { unsigned char error=0; s_transstart(); //transmission start error+=s_write_byte(STATUS_REG_W);//send command to sensor error+=s_write_byte(*p_value); //send value of status register return error; //error>=1 in case of no response form the sensor } // //*********************************************************************** // char s_measure(unsigned char *p_value, unsigned char *p_checksum, unsigned char mode) //*********************************************************************** // makes a measurement (humidity/temperature) with checksum char s_measure(unsigned char *p_value, unsigned char *p_checksum, unsigned char mode) { unsigned error=0; unsigned int i; s_transstart(); //transmission start switch(mode) { //send command to sensor case TEMP : error+=s_write_byte(MEASURE_TEMP); break; case HUMI : error+=s_write_byte(MEASURE_HUMI); break; default : break; } //wait until sensor has finished the measurement for (i=0;i<65535;i++) if(DATA==0) break; if(DATA) error+=1; // or timeout (~2 sec.) is reached *(p_value) =s_read_byte(ACK); //read the first byte (MSB) *(p_value+1)=s_read_byte(ACK); //read the second byte (LSB) *p_checksum =s_read_byte(noACK); //read checksum return error; } // //*********************************************************************** // void init_uart() //*********************************************************************** // Initializes the UART so the final data can be sent away, e.g. to a PC //9600 bps @ 11.059 MHz void init_uart() { SCON = 0x52; TMOD = 0x20; TCON = 0x69; TH1 = 0xfd; } // //*********************************************************************** // void calc_sth11(float *p_humidity ,float *p_temperature) //*********************************************************************** // calculates temperature [ C] and humidity [%RH] // input : humi [Ticks] (12 bit) // temp [Ticks] (14 bit) // output: humi [%RH] // temp [ C] void calc_sth11(float *p_humidity ,float *p_temperature) { const float C1=-4.0; // for 12 Bit const float C2= 0.0405; // for 12 Bit const float C3=-0.0000028; // for 12 Bit const float T1=0.01; // for 14 Bit @ 5V const float T2=0.00008; // for 14 Bit @ 5V float rh=*p_humidity; // rh: Humidity [Ticks] 12 Bit float t=*p_temperature; // t: Temperature [Ticks] 14 Bit float rh_lin; // rh_lin: Humidity linear float rh_true; // rh_true: Temperature compensated humidity float t_C; // t_C : Temperature [ C] t_C=t*0.01 ? 40; //calc. Temperature from ticks to [ C] rh_lin=C3*rh*rh + C2*rh + C1; //calc. Humidity from ticks to [%RH] rh_true=(t_C-25)*(T1+T2*rh)+rh_lin; //calc. Temperature compensated humidity [%RH] if(rh_true>100)rh_true=100; //cut if the value is outside of if(rh_true<0.1)rh_true=0.1; //the physical possible range *p_temperature=t_C; //return temperature [ C] *p_humidity=rh_true; //return humidity[%RH] } // //*********************************************************************** // float calc_dewpoint(float h,float t) //*********************************************************************** // calculates dew point // input: humidity [%RH], temperature [ C] // output: dew point [ C] float calc_dewpoint(float h,float t) { float k,dew_point ; k = (log10(h)-2)/0.4343 + (17.62*t)/(243.12+t); dew_point = 243.12*k/(17.62-k); return dew_point; } //*********************************************************************** // void main() //*********************************************************************** // sample program that shows how to use SHT11 functions // 1. connection reset // 2. measure humidity [ticks](12 bit) and temperature [ticks](14 bit) // 3. calculate humidity [%RH] and temperature [ C] // 4. calculate dew point [ C] // 5. print temperature, humidity, dew point void main() { value humi_val,temp_val; float dew_point; unsigned char error,checksum; unsigned int i; init_uart(); s_connectionreset(); // while(1) { error=0; error+=s_measure((unsigned char*) &humi_val.i,&checksum,HUMI); //measure humidity error+=s_measure((unsigned char*) &temp_val.i,&checksum,TEMP); //measure temperature if(error!=0) s_connectionreset(); //in case of an error: connection reset else { humi_val.f=(float)humi_val.i; //converts integer to float temp_val.f=(float)temp_val.i; //converts integer to float calc_sth11(&humi_val.f,&temp_val.f); //calculate humidity, temperature dew_point=calc_dewpoint(humi_val.f,temp_val.f); //calculate dew point //send final data to serial interface (UART) printf(“temp:%5.1fC humi:%5.1f%% dew point:%5.1fC ”,temp_val.f,humi_val.f,dew_point); } //-----------wait approx. 0.8s to avoid heating up SHTxx--------------- for (i=0;i<40000;i++); //(be sure that the compiler doesn’t eliminate this line!) } } AVRTOOLS™ |
| 
|
 ENC28J60 Ethernet to SPI Header Board |
 SHT11 습도센서 SX18 인터페이스 |
바구니 : 
보관함 : 
오늘뷰 : 0
HOME
TOP
PREV
0 
0 
0