LCD12864 LCD display SHT11 temperature and humidity sensor program-EEWORLD

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Note: Lower versions of Keil software cannot be compiled successfully because they cannot handle floating-point operations.

#include

#define uint unsigned int

#define uchar unsigned char

#define noACK 0

#define ACK 1

#define STATUS_REG_W 0x06

#define STATUS_REG_R 0x07

#define MEASURE_TEMP 0x03

#define MEASURE_HUMI 0x05

#define RESET 0x1e

enum {TEMP,HUMI};

typedef union //Defines a shared type

{

unsigned int i;

float f;

} value;

sbit lcdrs=P2^0;

sbit lcdrw=P2^1;

sbit lcden=P2^2;

sbit SCK = P1^0;

sbit DATA = P1^1;

uchar table2[]="SHT11 temperature and humidity detection";

uchar table3[]="Temperature: ℃";

uchar table4[]="Humidity is:";

uchar table5[]=".";

uchar wendu[6];

uchar shidu[6];

void delay(int z)

{

int x,y;

for(x=z;x>0;x--)

for(y=125;y>0;y--);

}

void delay_50us(uint t)

{

uint j;

for(;t>0;t--)

for(j=19;j>0;j--);

}

void delay_50ms(uint t)

{

uint j;

for(;t>0;t--)

for(j=6245;j>0;j--);

}

void write_12864com(uchar com)

{

lcdrs=0;

lcdrw=0;

delay_50us(1);

P0=com;

lcden=1;

delay_50us(10);

lcden=0;

delay_50us(2);

}

void write_dat(uchar dat)

{

lcdrs=1;

lcdrw=0;

delay_50us(1);

P0=dat;

lcden=1;

delay_50us(10);

lcden=0;

delay_50us(2);

}

void init12864lcd(void)

{

delay_50ms(2);

write_12864com(0x30);

delay_50us(4);

write_12864com(0x30);

delay_50us(4);

write_12864com(0x0f);

delay_50us(4);

write_12864com(0x01);

delay_50us(240);

write_12864com(0x06);

delay_50us(10);

write_12864com(0x0c);

delay_50us(10);

}

void display1(void)

{

uchar i;

write_12864com(0x80);

for(i=0;i<18;i++)

{

write_dat(table2[i]);

delay_50us(1);

}

void display2(void)

{

uchar i;

write_12864com(0x90);

for(i=0;i<18;i++)

{

write_dat(table3[i]);

delay_50us(1);

}

void display3(void)

{

uchar i;

write_12864com(0x88);

for(i=0;i<8;i++)

{

write_dat(table4[i]);

delay_50us(1);

}

void displaywendu(void)

{

uchar i;

write_12864com(0x94);

for(i=0;i<3;i++)

{

write_dat(wendu[i]);

delay_50us(1);

}

for(i=0;i<1;i++)

{

write_dat(table5[i]);

delay_50us(1);

}

for(i=4;i<5;i++)

{

write_dat(wendu[i]);

delay_50us(1);

}

void displayshidu(void)

{

uchar i;

write_12864com(0x8C);

for(i=0;i<3;i++)

{

write_dat(shidu[i]);

delay_50us(1);

}

for(i=0;i<1;i++)

{

write_dat(table5[i]);

delay_50us(1);

}

for(i=4;i<5;i++)

{

write_dat(shidu[i]);

delay_50us(1);

}

//Write byte program

char s_write_byte(unsigned char value)

{

unsigned char i,error=0;

for (i=0x80;i>0;i>>=1) //The high bit is 1, and the circular right shift

{

if (i&value) DATA=1; // AND the number to be sent, the result is the bit to be sent

else DATA=0;

SCK=1;

_nop_();_nop_();_nop_(); //Delay 3us

SCK=0;

}

DATA=1; //Release data line

SCK=1;

error=DATA; //Check the response signal to confirm that the communication is normal

_nop_();_nop_();_nop_();

SCK=0;

DATA=1;

return error; //error=1 Communication error

}

//Read byte program

char s_read_byte(unsigned char ack)

{

unsigned char i,val=0;

DATA=1; //Release data line

for(i=0x80;i>0;i>>=1) //The high bit is 1, and the loop moves right

{

SCK=1;

if(DATA) val=(val|i); //Read the value of a data line

SCK=0;

}

DATA=!ack; //If it is verification, end the communication after reading;

SCK=1;

_nop_();_nop_();_nop_(); //Delay 3us

SCK=0;

_nop_();_nop_();_nop_();

DATA=1; //Release data line

return val;

}

//Start the transfer

void s_transstart(void)

{

DATA=1; SCK=0; //Prepare

_nop_();

SCK=1;

_nop_();

DATA=0;

_nop_();

SCK=0;

_nop_();_nop_();_nop_();

SCK=1;

_nop_();

DATA=1;

_nop_();

SCK=0;

}

//Reset the connection

void s_connectionreset(void)

{

unsigned char i;

DATA=1; SCK=0; //Prepare

for(i=0;i<9;i++) //DATA remains high, SCK clock triggers 9 times, sending starts transmission, communication is reset

{

SCK=1;

SCK=0;

}

s_transstart(); //Start transmission

}

//Soft reset procedure

char s_softreset(void)

{

unsigned char error=0;

s_connectionreset(); //Start connection reset

error+=s_write_byte(RESET); //Send reset command

return error; //error=1 Communication error

}

//Temperature and humidity measurement

char s_measure(unsigned char *p_value, unsigned char *p_checksum, unsigned char mode)

{

unsigned error=0;

unsigned int i;

s_transstart(); //Start transmission

switch(mode) //Select the send command

{

case TEMP : error+=s_write_byte(MEASURE_TEMP); break; //Measure temperature

case HUMI : error+=s_write_byte(MEASURE_HUMI); break; //Measure humidity

default : break;

}

for (i=0;i<65535;i++) if(DATA==0) break; //Wait for the measurement to end

if(DATA) error+=1; // If the data line is not pulled low for a long time, it means the measurement is wrong

*(p_value) =s_read_byte(ACK); //Read the first byte, high byte (MSB)

*(p_value+1)=s_read_byte(ACK); //Read the second byte, low byte (LSB)

*p_checksum =s_read_byte(noACK); //read CRC checksum

return error; // error=1 Communication error

}

// Temperature and humidity value scale conversion and temperature compensation

void calc_sth10(float *p_humidity, float *p_temperature)

{

const float C1=-4.0; // 12-bit humidity accuracy correction formula

const float C2=+0.0405; // 12-bit humidity accuracy correction formula

const float C3=-0.0000028; // 12-bit humidity accuracy correction formula

const float T1=+0.01; // 14-bit temperature accuracy 5V condition correction formula

const float T2=+0.00008; // 14-bit temperature accuracy 5V condition correction formula

float rh=*p_humidity; // rh: 12-bit humidity

float t=*p_temperature; // t: 14-bit temperature

float rh_lin; // rh_lin: humidity linear value

float rh_true; // rh_true: humidity true value

float t_C; // t_C : temperature in °C

t_C=t*0.01 - 40; //compensation temperature

rh_lin=C3*rh*rh + C2*rh + C1; //Relative humidity nonlinear compensation

rh_true=(t_C-25)*(T1+T2*rh)+rh_lin; //Relative humidity temperature dependence compensation

if(rh_true>100)rh_true=100; //maximum humidity correction

if(rh_true<0.1)rh_true=0.1; //minimum humidity correction

*p_temperature=t_C; //Return temperature result

*p_humidity=rh_true; //Return humidity result

}

void main(void)

{

unsigned int temp,humi;

value humi_val,temp_val; //Define two communities, one for humidity and one for temperature

unsigned char error; //Used to check if an error occurs

unsigned char checksum; //CRC

init12864lcd();

display1();

display2();

display3();

s_connectionreset(); //Start connection reset

while(1)

{

error=0; //Initialize error=0, that is, no error

error+=s_measure((unsigned char*)&temp_val.i,&checksum,TEMP); //temperature measurement

error+=s_measure((unsigned char*)&humi_val.i,&checksum,HUMI); //humidity measurement

if(error!=0) s_connectionreset(); ////If an error occurs, the system is reset

else

{

humi_val.f=(float)humi_val.i; //Convert to floating point number

temp_val.f=(float)temp_val.i; //Convert to floating point number

calc_sth10(&humi_val.f,&temp_val.f); //Correction of relative humidity and temperature

temp=temp_val.f*10;

humi=humi_val.f*10;

wendu[0]=temp/1000+'0'; //temperature in hundreds

wendu[1]=temp00/100+'0'; //Temperature tens digit

wendu[2]=temp0/10+'0'; //Temperature units

wendu[3]=0x2E; //decimal point

wendu[4]=temp+'0'; //The first decimal place of temperature

displaywendu();

shidu[0]=humi/1000+'0'; //humidity in hundreds

shidu[1]=humi00/100+'0'; //humidity tens digit

shidu[2]=humi0/10+'0'; //Humidity units

shidu[3]=0x2E; //decimal point

shidu[4]=humi+'0'; //The first decimal place of humidity

displayshidu();

}

delay(800); //Wait long enough for the next conversion

}

Keywords：LCD12864 Reference address：LCD12864 LCD display SHT11 temperature and humidity sensor program

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