Revision 1:d3ed713f8354, committed 2014-05-15

Comitter:

loopsva

Date:

Thu May 15 19:12:11 2014 +0000

Parent:

0:2dab43acb3a4

Child:

2:8fbe84ed61e6

Commit message:

Added serial number access structure. Cleaned up documentation.

Changed in this revision

--- a/htu21d.cpp	Wed May 14 00:31:30 2014 +0000
+++ b/htu21d.cpp	Thu May 15 19:12:11 2014 +0000
@@ -1,7 +1,9 @@
 /**
-HTU21D driver for mbed.  Includes RTOS hooks if RTOS is detected during compile
+HTU21D / HPP828E031 driver for mbed.
+- Includes RTOS hooks if RTOS is detected during compile.
 Author: Kevin Braun
 **/
+
 #include "htu21d.h"
 
 #ifdef RTOS_H
@@ -12,11 +14,15 @@
 //Contstructor
 
 htu21d::htu21d(PinName sda, PinName scl) : _i2c(sda, scl) {
-//    _i2c = new I2C(sda, scl);
+    _i2c.frequency(400000);
+}
+
+htu21d::htu21d(PinName sda, PinName scl, int i2cFrequency) : _i2c(sda, scl) {
+    _i2c.frequency(i2cFrequency);
 }
 
 //--------------------------------------------------------------------------------------------------------------------------------------//
-//De-contstructor
+//Destructor
 
 htu21d::~htu21d() {
 }
@@ -36,9 +42,10 @@
     if(htu21 == 1) {
         _i2c.write(HTU21DRESET);            //soft reset, must wait 15mS
         _i2c.stop();
+        wait_ms(16);                        //must wait a least 15mS for reset to finish
+        htu21d::getSNReg();                 //go load up the s/n registers
     }
-    wait_ms(16);                            //must wait a least 15mS for reset to finish
-    
+
 #ifdef RTOS_H
     MutexI2cWait.unlock();
 #endif
@@ -166,7 +173,7 @@
             _i2c.stop();
         }
         wait_us(50);
-    } while((htu21cnt < 1000) && (htu21 == 0)); //htu21cnt takes 510 to get temp, 160 for humidity
+    } while((htu21cnt < 10000) && (htu21 == 0)); //htu21cnt takes 510 to get temp, 160 for humidity
  
 #ifdef RTOS_H
     MutexI2cWait.unlock();
@@ -232,3 +239,58 @@
     double h21DtzD = (h21DtzB * h21DtzC) / (h21DtzA - h21DtzC);
     return (h21DtzD);
 }
+
+//--------------------------------------------------------------------------------------------------------------------------------------//
+//Get the HTU21D serial number registers. Returns 64 bit register.
+//should return 0x4854 00xx xxxx 32xx
+
+void htu21d::getSNReg() {
+
+#ifdef RTOS_H
+    MutexI2cWait.lock();
+#endif
+
+    //get 16 bit SNC register, 8 bit SNC-CRC, 16 bit SNA register, 8 bit SNA-CRC
+    int htu21 = 0;
+    _i2c.start();
+    htu21 = _i2c.write(HTU21Di2cWRITE);     //i2c, 1 = ack
+    if(htu21 == 1) {
+        _i2c.write(HTU21SNAC1);
+        _i2c.write(HTU21SNAC2);
+        _i2c.start();
+        htu21 = _i2c.write(HTU21Di2cREAD);
+        HTU21sn.HTU21D_snc = _i2c.read(1) << 8;
+        HTU21sn.HTU21D_snc |= _i2c.read(1);
+        HTU21sn.HTU21D_crcc = _i2c.read(1);
+        HTU21sn.HTU21D_sna = _i2c.read(1) << 8;
+        HTU21sn.HTU21D_sna |= _i2c.read(1);
+        HTU21sn.HTU21D_crca = _i2c.read(0);
+        _i2c.stop();
+    }
+    
+    //get 32 bit SNB register, 32 bit SNB-CRC - regs are intermixed
+    htu21 = 0;
+    _i2c.start();
+    htu21 = _i2c.write(HTU21Di2cWRITE);     //i2c, 1 = ack
+    if(htu21 == 1) {
+        _i2c.write(HTU21SNB1);
+        _i2c.write(HTU21SNB2);
+        _i2c.start();
+        htu21 = _i2c.write(HTU21Di2cREAD);
+        HTU21sn.HTU21D_snb = _i2c.read(1) << 24;
+        HTU21sn.HTU21D_crcb = _i2c.read(1) << 24;
+        HTU21sn.HTU21D_snb |= _i2c.read(1) << 16;
+        HTU21sn.HTU21D_crcb |= _i2c.read(1) << 16;
+        HTU21sn.HTU21D_snb |= _i2c.read(1) << 8;
+        HTU21sn.HTU21D_crcb |= _i2c.read(1) << 8;
+        HTU21sn.HTU21D_snb |= _i2c.read(1);
+        HTU21sn.HTU21D_crcb |= _i2c.read(0);
+        _i2c.stop();
+    }
+    
+#ifdef RTOS_H
+    MutexI2cWait.unlock();
+#endif
+
+}
+

--- a/htu21d.h	Wed May 14 00:31:30 2014 +0000
+++ b/htu21d.h	Thu May 15 19:12:11 2014 +0000
@@ -1,5 +1,8 @@
 /**
- */
+HTU21D / HPP828E031 driver for mbed.
+- Includes RTOS hooks if RTOS is detected during compile.
+Author: Kevin Braun
+ **/
 
 #ifndef HTU21D_H
 #define HTU21D_H
@@ -16,116 +19,239 @@
 #define HTU21DhumNOHOLD     0xF5
 #define HTU21DRESET         0xFE
 
+#define HTU21SNAC1          0xFC
+#define HTU21SNAC2          0xC9
+#define HTU21SNB1           0xFA
+#define HTU21SNB2           0x0F
+
 #define HTU21DHEATER        0x04
 
 
-/**
- * Honeywell HTU21D digital humidity and temperature sensor.
- */
+    /**
+    * measurement specialties / Honeywell HTU21D digital humidity and temperature sensor.
+    * - Web site: http://www.meas-spec.com  
+    * - Part Number: HPP828E031
+    * - HTU21D = +-3% rh error at 55%
+    * - HTU20D = +-5% rh error at 55%
+    * - Main code generated from datasheet dated October 2013
+    * - Serial number code generated from App Note "HTU2X Serial Number Reading", dated Februrary 2014
+    * - No checksum checking is performed in this code
+    *
+    * @code
+    * //Tested on FRDM-K64F
+    *
+    * #include "mbed.h"
+    * #include "htu21d.h"
+    *
+    * #define SDA     PTE25 
+    * #define SCL     PTE24
+    *
+    * Serial pc(USBTX, USBRX);                  //local terminal
+    * htu21d htu(SDA, SCL);                     //Temp Hum || sda, scl
+    *
+    * float H21Temp = 0.0;                      //Temperture from HTU21D
+    * float H21Hum = 0.0;                       //Humidity from HTU21D
+    * float H21Dew = 0.0;                       //Dew Point from HTU21D
+    *
+    * //Note: If RTOS is used, Mutex for I2C must be initialized
+    * #ifdef RTOS_H
+    * Mutex MutexI2cWait;
+    * #endif
+    *
+    * int main() {
+    *     pc.baud(230400);                        //local terminal baud
+    *     pc.printf("\r\n\r\nK64F_HTU21D basic operation\r\n"); 
+    * 
+    *     //initialize the HTU21D
+    *     int htu21 = htu.softReset();
+    *     if(htu21 == 0) {
+    *         pc.printf(" - HTU21D broken...\r\n");
+    *     } else {
+    *         uint8_t HTU21DuserReg = htu.getUserReg();
+    *         pc.printf("HTU21D UserReg: 0x%02x   SN: 0x%04x %08x %04x\r\n", 
+    *                   HTU21DuserReg, htu.HTU21sn.HTU21D_sna, htu.HTU21sn.HTU21D_snb, htu.HTU21sn.HTU21D_snc);
+    *     }
+    * 
+    *     while(true) {
+    *         //get humidity, temperature and dew point from HTU21D
+    *         if(htu21 == 1) {    //if HTU21D didn't initialize, don't access HTU21D anymore
+    *             H21Hum = htu.getHum();
+    *             if((double)H21Hum == 255.0) pc.printf("\r\n*** HTU21D Hum error!!\r\n");
+    *             H21Temp = htu.getTemp();
+    *             if((double)H21Temp == 255.0) pc.printf("\r\n*** HTU21D Temp error!!\r\n");
+    *             H21Dew = htu.getDewPtFast();
+    *         }
+    *         pc.printf("Temp: %7.2f C %7.2f F   Hum: %4.1f %%   DewPt: %7.2f C\r\n", H21Temp, H21Hum, H21Dew);
+    *         wait(1.0);
+    *     }
+    * }
+    * @endcode
+    **/
 class htu21d {
 
 public:
     /**
-     * Constructor.
+     * Constructor
+     * - Fixed at I2C address 0x80
+     * - I2C speed set to 400000
      *
-     * @param sda and scl, mbed I2C interface pins.
+     * @param PinName sda and scl, mbed I2C interface pins
      */
     htu21d(PinName sda, PinName scl);
     /**
-     * De-constructor.
+     * Constructor
+     * - Fixed at I2C address 0x80
+     * - I2C speed set by user
      *
-     * @param --none--.
+     * @param PinName sda and scl, mbed I2C interface pins 
+     * @param int I2C frequency
+     */
+    htu21d(PinName sda, PinName scl, int i2cFrequency);
+    /**
+     * Destructor
+     *
+     * @param --none--
      */
     ~htu21d();
     /**
-     * Get HTU21D Temperature.
+     * Reset the HTU21D chip
+     * - Waits 15mS before exiting, allowing the chip reset to finish
+     * - Executes getSNReg() which loads up HTU21D serial number structure
      * 
-     * @param --none--.
+     * @param --none-- NOTE: run softReset() once at initialization time
      *
-     * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error.
+     * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error
     */
     int softReset();
     /**
-     * Get HTU21D user register.
+     * Get HTU21D user register
      * 
-     * @param --none--.
+     * @param --none--
      *
-     * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error.
+     * @return 8 bit user register value
     */
     uint8_t getUserReg();
     /**
-     * Turn ON the heater in the HTU21D.
+     * Turn ON the heater on the HTU21D
      * 
-     * @param --none--.
+     * @param --none--
      *
-     * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error.
+     * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error
     */
     int heaterOn();
     /**
-     * Turn OFF the heater in the HTU21D.
+     * Turn OFF the heater on the HTU21D
      * 
-     * @param --none--.
+     * @param --none--
      *
-     * @return --none--.
+     * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error
     */
     int heaterOff();
     /**
-     * Get heater on/off status in the HTU21D.
+     * Get heater on/off status of the HTU21D
      * 
-     * @param --none--.
+     * @param --none--
      *
-     * @return 4 = on, 0 = 0ff.
+     * @return 0x04 = on, 0 = off
     */
     uint8_t getHeater();
     /**
-     * Do a reset on the HTU21D.
+     * Get HTU21D Temperature
      * 
-     * @param --none--.
+     * @param --none--
      *
-     * @return float of Temperature in degrees C.  255.0 if error.
+     * @return float of Temperature in degrees C.  255.0 if error
     */
     float getTemp();
     /**
-     * Get HTU21D Humidity.
+     * Get HTU21D Humidity
      * 
-     * @param --none--.
+     * @param --none--
      *
-     * @return float of Humidity in percentage.  255.0 if error.
+     * @return float of Humidity in percentage.  255.0 if error
     */
     float getHum();
     /**
-     * Claculate the Dew Point.
+     * Calculate the Dew Point
      * 
-     * @param MUST run getTemp and getHum first!!
+     * @param --none-- NOTE: You MUST run getTemp() and getHum() first!!
      *
-     * @return float of Dew Point.
+     * @return float of Dew Point
     */
     float getDewPt();
     /**
-     * Claculate the Dew Point. 5x faster than getDewPt().
+     * Calculate the Dew Point fast
+     * - 5x faster than getDewPt()
+     * - slightly less accurate than getDewPt()
      * 
-     * @param MUST run getTemp and getHum first!!
+     * @param --none-- NOTE: You MUST run getTemp() and getHum() first!!
      *
-     * @return float of Dew Point.
+     * @return float of Dew Point
     */
     float getDewPtFast();
-
- 
+    /**
+     * Structure to access HTU21D's serial number 
+     * - HTU21D_sna is the hi  16 bit word of the s/n, always is 0x4854
+     * - HTU21D_snb is the mid 32 bit word of the s/n, 0x00--------
+     * - HTU21D_snc is the low 16 bit word of the s/n, 0x32--
+     * - The complete 64 bit s/n value is: 0x48 54 00 -- -- -- 32 --
+     * - The numbers shown are fixed fields
+     * - The '-' numbers are variable
+     * - For reference, the CRC values for the s/n are included
+    */    
+    struct HTU21snStruct {
+        uint16_t HTU21D_sna;            /**< Highest order 16 bit word of SN
+                                            - Value always = 0x4854
+                                            */
+        uint32_t HTU21D_snb;            /**< Middle order 32 bit word of SN
+                                            - Value = 0x00--------
+                                            - Highest byte always = 0x00
+                                            - Lower 3 bytes are variable
+                                            */
+        uint16_t HTU21D_snc;            /**< Lowest order 16 bit word of SN
+                                            - Value = 0x32--
+                                            - Highest byte always = 0x32
+                                            - Lowest byte is variable
+                                            */
+        uint8_t HTU21D_crca;            /**< Single byte checksum from HTU21D_sna
+                                            */  
+        uint32_t HTU21D_crcb;           /**< Four byte checksum from HTU21D_snb
+                                            */
+        uint8_t HTU21D_crcc;            /**< Single byte checksum from HTU21D_snc
+                                            */
+        HTU21snStruct() {
+            HTU21D_sna = 0;
+            HTU21D_snb = 0;
+            HTU21D_snc = 0;
+            HTU21D_crca = 0;
+            HTU21D_crcb = 0;
+            HTU21D_crcc = 0;
+        }
+    } HTU21sn;
 
 private:
     I2C _i2c;
     /**
-     * I2C access for getting raw Temperature and Humidity data.
+     * I2C access for getting raw Temperature and Humidity data
      * 
-     * @param 8 bit HTU21D register to get data from. Must use non-blocking regs.
+     * @param 8 bit HTU21D register to get data from. Must use non-blocking regs
      *
-     * @return 16 bit raw i2c data, ANDed to 14 bits 0xFFFC. 0000 if error.
+     * @return 16 bit raw i2c data, ANDed to 14 bits 0xFFFC. 0000 if error
     */
     uint16_t getData(uint8_t reg);
+    /**
+     * Get the HTU21D's serial number. 
+     * - Number returned is 0x4854 00-- ---- 32--
+     * - The numbers shown are fixed fields
+     * - The '-' numbers are variable
+     * 
+     * @param --none--
+     *
+     * @return --none--
+    */
+    void getSNReg();
     double theTempIs;
     double theHumIs;
-    float getTrash();
-
 };
 
 #endif