SHT10农田自动灌溉系统的仿真设计 -

#include"SHT10.h"
#define uchar unsigned char
/*--------------------------------------
;启动传输函数
;-------------------------------------*/
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;
}
/*--------------------------------------
;连接复位函数
;-------------------------------------*/
void s_connectionreset(void)
{
unsigned char i;
DATA=1; SCK=0;
for(i=0;i<9;i++)
{
SCK=1;
SCK=0;
}
s_transstart();
}
/*--------------------------------------
;SHT10写函数
;-------------------------------------*/
char s_write_byte(unsigned char value)
{
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-BU
else DATA=0;
SCK=1; //clk for SENSI-BUS
_nop_();_nop_();_nop_(); //pulswith approx. 3 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),DATA在第9个上升沿将被SHT10自动下拉为低电
_nop_();_nop_();_nop_();
SCK=0;
DATA=1; //release DATA-line
return error; //error=1 in case of no acknowledge //返回：0成功，1失败
}
/*--------------------------------------
;SHT10读函数
;-------------------------------------*/
char s_read_byte(unsigned char ack)
{
unsigned char i,val=0;
DATA=1;
for (i=0x80;i>0;i/=2)
{ SCK=1;
if (DATA) val=(val | i);
_nop_();_nop_();_nop_();
SCK=0;
}
if(ack==1)DATA=0;
else DATA=1; //如果是校验(ack==0)，读取完后结束通讯
_nop_();_nop_();_nop_();
SCK=1;
_nop_();_nop_();_nop_();
SCK=0;
_nop_();_nop_();_nop_();
DATA=1;
return val;
}
/*--------------------------------------
;测量温湿度函数
;-------------------------------------*/
char s_measure(unsigned char *p_value, unsigned char *p_checksum, unsigned char mode)
{
unsigned error=0;
unsigned int i;
s_transstart();
switch(mode)
{
case TEMP : error+=s_write_byte(MEASURE_TEMP);
break;
case HUMI : error+=s_write_byte(MEASURE_HUMI);
break;
default :
break;
}
for (i=0;i<65535;i++)
if(DATA==0) break;
if(DATA) error+=1;
*(p_value) =s_read_byte(ACK);
*(p_value+1)=s_read_byte(ACK);
*p_checksum =s_read_byte(noACK);
return error;
}
/*--------------------------------------
;温湿度补偿函数
;-------------------------------------*/
void calc_SHT10(float *p_humidity ,float *p_temperature)
{
const float C1=-4.0;
const float C2=+0.0405;
const float C3=-0.0000028;
const float T1=+0.01;
const float T2=+0.00008;
float rh=*p_humidity;
float t=*p_temperature;
float rh_lin;
float rh_true;
float t_C;
t_C=t*0.01 - 40;
rh_lin=C3*rh*rh + C2*rh + C1;
rh_true=(t_C-25)*(T1+T2*rh)+rh_lin;
if(rh_true>100)rh_true=100;
if(rh_true<0.1)rh_true=0.1;
*p_temperature=t_C;
*p_humidity=rh_true+C1;
}
//读状态寄存器
char s_read_statusreg(unsigned char*p_value, unsigned char *p_checksum)
//----------------------------------------------------------------------------------
// reads the status register with checksum(8-bit)
{
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
}
//写状态寄存器
char s_write_statusreg(unsigned char*p_value)
// writes the status register with checksum(8-bit)
{
unsigned char error=0;
s_transstart(); //transmission start
error+=s_write_byte(STATUS_REG_W);//sendcommand 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
}
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