Diff: Si7021.cpp

Revision:

2:b221ba23b37f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Si7021.cpp	Mon Jan 25 14:36:57 2016 +0000
@@ -0,0 +1,103 @@
+#include "Si7021.h"
+
+SI7021_I2C::SI7021_I2C(PinName sda, PinName scl) : i2c_(sda, scl) 
+{    
+    //400kHz, allowing us to use the fastest data rates.
+    i2c_.frequency(400000);   
+}
+
+uint8_t SI7021_I2C::readBytes(uint8_t *values, int8_t length, bool waitConversion)
+{
+    uint8_t Status=0;
+
+    if(!i2c_.write(SI7021_ADDR, (const char*)values, 1,0))
+        Status=1;
+    
+    //Wait the measurement time
+    if(waitConversion)
+        wait_ms(23);
+    
+    if(!i2c_.read(SI7021_ADDR, (char*)values, length,0))
+        Status=1;
+    return(Status);
+}
+
+
+float SI7021_I2C::Measure_Temp(void)
+{
+    float Temperature;
+    uint16_t ConvValue;
+    uint8_t *Ptr;
+    uint8_t Data[2];
+    
+    Data[0]=SI7021_MEASURE_TEMPERATURE_HOLD_MASTER;
+    if(readBytes(Data,2, 1))
+    {
+        Ptr=(uint8_t*)&ConvValue;
+        Ptr[0]=Data[1];
+        Ptr[1]=Data[0];
+        
+        Temperature=(((float)ConvValue)/65536)*175-46.85;
+    }
+    else
+    {
+        Temperature=1234;
+    }
+    
+    return(Temperature);
+}
+
+float SI7021_I2C::get_HumidityTemp(void)
+{
+    float Temperature;
+    uint16_t ConvValue;
+    uint8_t *Ptr;
+    uint8_t Data[2];
+    
+    Data[0]=SI7021_READ_TEMPERATURE;
+    if(readBytes(Data,2, 0))
+    {
+        Ptr=(uint8_t*)&ConvValue;
+        Ptr[0]=Data[1];
+        Ptr[1]=Data[0];
+        
+        Temperature=(((float)ConvValue)/65536)*175-46.85;
+    }
+    else
+    {
+        Temperature=1234;
+    }
+    
+    return(Temperature);
+}
+
+void SI7021_I2C::Measure_Humidity_Temp(float *humidity, float *temperature)
+{
+    float Humidity;
+    uint16_t ConvValueHum;
+    uint8_t *Ptr;
+    uint8_t Data[2];
+    
+    Data[0]=SI7021_MEASURE_RH_NO_HOLD_MASSTER;
+    
+    if(readBytes(Data,2, 1))
+    {
+    
+        Ptr=(uint8_t*)&ConvValueHum;
+        Ptr[0]=Data[1];
+        Ptr[1]=Data[0];
+        
+        Humidity=(((float)ConvValueHum)/65536)*125-6;
+        
+        if(Humidity<0)
+            Humidity=0;
+        if(Humidity>100)
+            Humidity=100;           
+    }
+    else
+        Humidity=1234;  
+
+    *humidity = Humidity;
+    *temperature = get_HumidityTemp();
+    
+}