Revision 0:cb02bfe8cf44, committed 2016-09-14

Comitter:

Ksenia

Date:

Wed Sep 14 15:22:42 2016 +0000

Commit message:

Initial commit

Changed in this revision

diff -r 000000000000 -r cb02bfe8cf44 HYT.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HYT.cpp	Wed Sep 14 15:22:42 2016 +0000
@@ -0,0 +1,42 @@
+#include "HYT.h"
+#include "mbed.h"
+
+HYT::HYT(PinName sda, PinName scl) : _i2c(sda, scl)
+{
+}
+
+/*************************************************************************************************************************/
+void HYT::MRCommand(void)
+{
+    _i2c.write(HYT_ADDR, 0, 0);
+}
+
+
+/*************************************************************************************************************************/
+int HYT::DFCommand(void)
+{
+    char    dataI2C[4];
+    int     stateBit;
+    int     humidityRaw;
+    int     temperatureRaw;
+
+    _i2c.read(HYT_ADDR, dataI2C, 4);
+
+    stateBit = (dataI2C[0] & 0x40) >> 6;
+    if (stateBit == 0) {
+        humidityRaw = ((dataI2C[0] & 0x3F) << 8) | dataI2C[1];
+        temperatureRaw = ((dataI2C[2] << 8) | dataI2C[3]) >> 2;
+        if (temperatureRaw < 0x3FFF && humidityRaw < 0x3FFF) {
+            temperature = ((float)(temperatureRaw) * 165.0f / 16383.0f) - 40.0f;
+            humidity = (float)humidityRaw * 100.0f / 16383.0f;
+        } else {
+            // sensor returns wrong data (1111...11)
+            return -1;
+        }
+    } else {
+        // no new value received from sensor
+        return 0;    
+    } 
+    
+    return 0;
+}
\ No newline at end of file

diff -r 000000000000 -r cb02bfe8cf44 HYT.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HYT.h	Wed Sep 14 15:22:42 2016 +0000
@@ -0,0 +1,85 @@
+#ifndef MBED_HYT_H
+#define MBED_HYT_H
+
+#include "mbed.h"
+
+/**
+ * IST HYT Humidity and Temperature Sensor
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "HYT.h"
+ * 
+ * Serial              pc(USBTX, USBRX);
+ * Ticker              timeKeeping;
+ * HYT                 SENSOR (I2C_SDA, I2C_SCL);
+ * 
+ * // HYT sensor polling cycle
+ * void dataUpdate(void)
+ * {
+ *     SENSOR.MRCommand();
+ *     wait_ms(100);
+ *     SENSOR.DFCommand();
+ * }
+ * 
+ * void secondsCallback(void) {
+ *     pc.printf("Humidity level: %.1f\r\n%", SENSOR.humidity);
+ *     pc.printf("Temperature level: %.1f\r\n%", SENSOR.temperature);
+ *     pc.printf("-------------------------------\r\n%", SENSOR.temperature);
+ * }
+ * 
+ * int main()
+ * {
+ *     timeKeeping.attach(&secondsCallback, 1.0f);
+ *     while(1) {
+ *          dataUpdate();
+ *     }
+ * }
+ * @endcode
+ */
+
+
+#define HYT_ADDR 0x50 // 01010000
+
+class HYT
+{
+    
+public:
+    /**
+     * HYT constructor.
+     *
+     * @param   sda mbed pin to use for SDA line of I2C interface.
+     * @param   scl mbed pin to use for SCL line of I2C interface.
+     * 
+     * Remember about pull-up resistors on sda and scl. Recommended value is 2.4 kΩ
+     */
+    HYT(PinName sda, PinName scl);
+
+    /**
+     * @brief   The totals (temperature in Celsius, relative humidity in percentages)
+     */
+    float humidity;
+    float temperature;
+    
+    /**
+     * @brief   Send "Measuring Request" command
+     * @details Initiates a measuring cycle of HYT sensor
+     * @details More information: http://www.ist-ag.com/eh/ist-ag/resource.nsf/imgref/Download_AHHYTM_E2.2.5.pdf/$FILE/AHHYTM_E2.2.5.pdf
+     */     
+    void MRCommand(void);
+    
+    /**
+     * @brief   Send "Data Fetch" command & processing the data
+     * @details Fetch the last measured value of humidity and temperature from sensor
+     * @details Calculate values of temperature in Celsius, relative humidity in percentages
+     * @details More information: http://www.ist-ag.com/eh/ist-ag/resource.nsf/imgref/Download_AHHYTM_E2.2.5.pdf/$FILE/AHHYTM_E2.2.5.pdf
+     * @returns 0 if no errors, -1 if no new value received from sensor.
+     */    
+     int DFCommand(void);
+     
+private:
+
+    I2C _i2c;
+};
+
+#endif
\ No newline at end of file