SHT71温度传感器与其他设备共用出错的问题

atlas

1、使用以下程序单纯在Arduino上测试SHT71成功，串口正常输出温度湿度数据。
2、但是当和别的设备一起工作时就出问题，例如I2C总线的AM2321等，一直显示ACK错误，貌似设备不再返回数据，AM2321也不再正常输出。而将SHT71的程序移除，其他设备的程序也就恢复正常。
3、请问，这段程序没有调用库，完全是IO口操作，而且IO口不一致，为什么还会和其他I2C总线的设备冲突。

1. int SHT_clockPin = 3;  // pin used for clock
   
2. int SHT_dataPin  = 2;  // pin used for data
   
3. 
   
4. void setup(){
   
5.   Serial.begin(9600); // open serial at 9600 bps
   
6. }
   
7. 
   
8. void loop(){
   
9.   //these can take a bit to get the values (100ms or so)
   
10.   float temperature = getTemperature();
    
11.   float humidity = getHumidity();
    
12. 
    
13.   Serial.print(temperature);
    
14.   Serial.print(" | ");
    
15.   Serial.println(humidity);
    
16. 
    
17. }
    
18. 
    
19. 
    
20. 
    
21. 
    
22. 
    
23. 
    
24. float getTemperature(){
    
25.   //Return Temperature in Celsius
    
26.   SHT_sendCommand(B00000011, SHT_dataPin, SHT_clockPin);
    
27.   SHT_waitForResult(SHT_dataPin);
    
28. 
    
29.   int val = SHT_getData(SHT_dataPin, SHT_clockPin);
    
30.   SHT_skipCrc(SHT_dataPin, SHT_clockPin);
    
31.   return (float)val * 0.01 - 40; //convert to celsius
    
32. }
    
33. 
    
34. float getHumidity(){
    
35.   //Return  Relative Humidity
    
36.   SHT_sendCommand(B00000101, SHT_dataPin, SHT_clockPin);
    
37.   SHT_waitForResult(SHT_dataPin);
    
38.   int val = SHT_getData(SHT_dataPin, SHT_clockPin);
    
39.   SHT_skipCrc(SHT_dataPin, SHT_clockPin);
    
40.   return -4.0 + 0.0405 * val + -0.0000028 * val * val;
    
41. }
    
42. 
    
43. 
    
44. void SHT_sendCommand(int command, int dataPin, int clockPin){
    
45.   // send a command to the SHTx sensor
    
46.   // transmission start
    
47.   pinMode(dataPin, OUTPUT);
    
48.   pinMode(clockPin, OUTPUT);
    
49.   digitalWrite(dataPin, HIGH);
    
50.   digitalWrite(clockPin, HIGH);
    
51.   digitalWrite(dataPin, LOW);
    
52.   digitalWrite(clockPin, LOW);
    
53.   digitalWrite(clockPin, HIGH);
    
54.   digitalWrite(dataPin, HIGH);
    
55.   digitalWrite(clockPin, LOW);
    
56. 
    
57.   // shift out the command (the 3 MSB are address and must be 000, the last 5 bits are the command)
    
58.   shiftOut(dataPin, clockPin, MSBFIRST, command);
    
59. 
    
60.   // verify we get the right ACK
    
61.   digitalWrite(clockPin, HIGH);
    
62.   pinMode(dataPin, INPUT);
    
63. 
    
64.   if (digitalRead(dataPin)) Serial.println("ACK error 0");
    
65.   digitalWrite(clockPin, LOW);
    
66.   if (!digitalRead(dataPin)) Serial.println("ACK error 1");
    
67. }
    
68. 
    
69. 
    
70. void SHT_waitForResult(int dataPin){
    
71.   // wait for the SHTx answer
    
72.   pinMode(dataPin, INPUT);
    
73. 
    
74.   int ack; //acknowledgement
    
75. 
    
76.   //need to wait up to 2 seconds for the value
    
77.   for (int i = 0; i < 1000; ++i){
    
78.     delay(2);
    
79.     ack = digitalRead(dataPin);
    
80.     if (ack == LOW) break;
    
81.   }
    
82. 
    
83.   if (ack == HIGH) Serial.println("ACK error 2");
    
84. }
    
85. 
    
86. int SHT_getData(int dataPin, int clockPin){
    
87.   // get data from the SHTx sensor
    
88. 
    
89.   // get the MSB (most significant bits)
    
90.   pinMode(dataPin, INPUT);
    
91.   pinMode(clockPin, OUTPUT);
    
92.   byte MSB = shiftIn(dataPin, clockPin, MSBFIRST);
    
93. 
    
94.   // send the required ACK
    
95.   pinMode(dataPin, OUTPUT);
    
96.   digitalWrite(dataPin, HIGH);
    
97.   digitalWrite(dataPin, LOW);
    
98.   digitalWrite(clockPin, HIGH);
    
99.   digitalWrite(clockPin, LOW);
    
100. 
     
101.   // get the LSB (less significant bits)
     
102.   pinMode(dataPin, INPUT);
     
103.   byte LSB = shiftIn(dataPin, clockPin, MSBFIRST);
     
104.   return ((MSB << 8) | LSB); //combine bits
     
105. }
     
106. 
     
107. void SHT_skipCrc(int dataPin, int clockPin){
     
108.   // skip CRC data from the SHTx sensor
     
109.   pinMode(dataPin, OUTPUT);
     
110.   pinMode(clockPin, OUTPUT);
     
111.   digitalWrite(dataPin, HIGH);
     
112.   digitalWrite(clockPin, HIGH);
     
113.   digitalWrite(clockPin, LOW);
     
114. }

复制代码

atlas

如果单独运行以上程序，就能正常输出
26.00 | 73.98
26.04 | 73.98
26.05 | 73.95
26.06 | 73.92
但如果和其他传感器一起运行，没有改变任何硬件，更换输入的程序，就显示以下输出：
ACK error 0
ACK error 2
ACK error 0
ACK error 2
-40.01 | -4.04