📄 sht11.lst
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C51 COMPILER V8.08 SHT11 04/07/2009 22:03:19 PAGE 1
C51 COMPILER V8.08, COMPILATION OF MODULE SHT11
OBJECT MODULE PLACED IN SHT11.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE SHT11.C BROWSE DEBUG OBJECTEXTEND
line level source
1 /******************************************************************/
2 /* temperature模and humidity measure */
3 /* display the data on the 1602; */
4 /* first line display temprrature */
5 /* two line display humidity */
6 /******************************************************************/
7 #include<reg52.h>
8 #include"intrins.h" /*keil library for _nop() operation*/
9 #include"stdio.h"
10 #include"math.h"
11 #include"absacc.h" /*keil library*/
12
13
14 #define ACK 1
15 #define noACK 0
16 #define measure_temp 0x03 /*command to measure temperature*/
17 #define measure_humi 0x05 /*command to measure humidity*/
18 #define RESET 0x1e /*soft reset*/
19
20
21 #define uchar unsigned char
22 #define uint unsigned int
23 #define ulong unsigned long
24 #define LCD_DATA P0 /*LCD data import*/
25
26
27
28 sbit RS =P2^0;
29 sbit RW =P2^1;
30 sbit E =P2^2;
31 sbit DATA =P1^0;
32 sbit SCK =P1^1;
33
34
35
36
37 typedef union //reserve measured value for temperature or humidity
38 {
39 uint i;
40 float f;
41 }Value;
42
43
44
45
46 typedef struct
47 {
48 unsigned char gewei;
49 unsigned char shiwei;
50 unsigned char DATAstrins1[6];
51 unsigned char DATAstrins2[6];
52 }Systemtime;
53
54
55
C51 COMPILER V8.08 SHT11 04/07/2009 22:03:19 PAGE 2
56
57
58 char Write_Byte(uchar value) //write a byte on the sen_bus and checks the acknowledge
59 {
60 1 uchar i,error;
61 1 for(i=0x80;i>0;i/=2) // continuous right shift 8 bit
62 1 {
63 2 if(value&i)DATA =1; //get the DATA
64 2 else DATA =0;
65 2 SCK =1;
66 2 _nop_();
67 2 _nop_();
68 2 _nop_(); //delay 5 us
69 2 SCK =0;
70 2 // drop edge
71 2 }
72 1 DATA =1; //release DATA
73 1 SCK =1; //checks answer sequence
74 1 error =DATA; //checks the answer state ,if the acknowledge the DATA =0;
75 1 SCK =0;
76 1 return error;
77 1
78 1 }
79
80
81
82 char Read_Byte(uchar ack)
83 {
84 1 uchar i,val =0;
85 1 DATA =1; //release the DATA line
86 1 for(i=0x80;i>0;i/=2) // continuous right shift 8 bit
87 1 {
88 2 SCK =1;
89 2 if(DATA)
90 2 val =(val|i);
91 2 SCK =0;
92 2
93 2
94 2 }
95 1 DATA =!ack; //if acknowledge DATA =0;
96 1 SCK =1;
97 1 _nop_(); _nop_(); _nop_(); //delay 5 us
98 1 SCK =0;
99 1 DATA =1; //release the DATA line
100 1 return val;
101 1
102 1 }
103
104
105
106 void Transmit_Start(void) //transmit start
107 {
108 1 DATA =1;
109 1 SCK =0;
110 1 _nop_();
111 1 SCK =1;
112 1 _nop_();
113 1 DATA =0;
114 1 _nop_();
115 1 SCK =0;
116 1 _nop_();
117 1 _nop_();
C51 COMPILER V8.08 SHT11 04/07/2009 22:03:19 PAGE 3
118 1 _nop_();
119 1 SCK =1;
120 1 _nop_();
121 1 DATA =1;
122 1 _nop_();
123 1 SCK =0;
124 1
125 1 }
126
127
128
129
130 void Connection_Reset(void) //if communication breaked , make use of the sequense start the commnicati
-on
131 {
132 1 unsigned char i;
133 1 DATA =1;
134 1 SCK =0;
135 1 for(i=9;i>0;i--) //continuous 9 drop edge for connection the transmit
136 1 {
137 2 SCK=1;
138 2 SCK=0;
139 2
140 2 }
141 1 Transmit_Start(); //transmit start
142 1
143 1 }
144
145
146
147 char Soft_Reset(void) //reset the SHT11 and clear the value of the register
148 {
149 1 uchar error =0;
150 1 Connection_Reset();
151 1 error += Write_Byte(RESET);
152 1 return error; //return the error for judgment answer
153 1
154 1 }
155
156
157
158 char Measure_Mode(uchar *P_Value, uchar *P_Checksum, uchar Mode) //make sure the style to measure
159 {
160 1 uchar error=0;
161 1 uchar i;
162 1 Transmit_Start();
163 1 switch(Mode)
164 1 {
165 2 case 0:error +=Write_Byte(measure_temp);break; // judgment the mode of measure
166 2 case 1:error +=Write_Byte(measure_humi);break;
167 2 default : break;
168 2
169 2 }
170 1 for(i=65535;i>0;i--)
171 1 if(DATA==0)break; //wait until sht11 complete the measure
172 1 if(DATA) error +=1; //time overflow 2second
173 1 *P_Value =Read_Byte(ACK); //get the high byte
174 1 *(P_Value+1) =Read_Byte(ACK); //get the low byte
175 1 *P_Checksum =Read_Byte(noACK); //get the checksum
176 1 return error;
177 1 }
178
C51 COMPILER V8.08 SHT11 04/07/2009 22:03:19 PAGE 4
179
180
181 void Calculate_SHT11(float *P_Temperature , float *P_Humidity) // calculate the temperature and humidity a
-fter compensated
182 {
183 1 const float C1=-4.0; //for 12 Bit
184 1 const float C2=+0.0405; //for 12 Bit
185 1 const float C3=-0.0000028; //for 12 Bit
186 1 const float T1=+0.01; //for 14 Bit @ 5V
187 1 const float T2=+0.00008; //for 14 Bit @ 5V
188 1
189 1 float rh=*P_Humidity; //rh: Humidity [Ticks] 12 Bit
190 1 float t=*P_Temperature; //t: Temperature [Ticks] 14 Bit
191 1 float rh_lin; //rh_lin: Humidity linear
192 1 float rh_true; //rh_true: Temperature compensated humidity
193 1 float t_C; //t_C : Temperature [癈]*/
194 1
195 1 t_C=t*0.01 - 40; //calc. temperature from ticks to
196 1 rh_lin=C3*rh*rh + C2*rh + C1; //calc. humidity from ticks to [%RH]
197 1 rh_true=(t_C-25)*(T1+T2*rh)+rh_lin; //calc. temperature compensated humidity [%RH]
198 1 if(rh_true>100)rh_true=100; //cut if the value is outside of
199 1 if(rh_true<0.1)rh_true=0.1; //the physical possible range
200 1
201 1 *P_Temperature=t_C; //return temperature
202 1 *P_Humidity=rh_true; //return humidity[%RH]
203 1
204 1 }
205
206
207
208 /***************************************************************************************/
209 void DelayUs(void) //delay 2 us;
210 {
211 1 _nop_();_nop_();
212 1 }
213
214
215 void DelayMs(uint a) //delay a*1Ms
216 {
217 1 uint i,j;
218 1 for(i=a;i>0;i--)
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