Digital humidity sensor with temperature output
Revision 2:ad5e3555c7ef, committed 2017-09-05
- Comitter:
- mcm
- Date:
- Tue Sep 05 13:18:23 2017 +0000
- Parent:
- 1:da1f21719567
- Commit message:
- The library was completed and tested, it works as expected.
Changed in this revision
| HTU21D.cpp | Show annotated file Show diff for this revision Revisions of this file |
| HTU21D.h | Show annotated file Show diff for this revision Revisions of this file |
--- a/HTU21D.cpp Thu Aug 31 20:28:28 2017 +0000
+++ b/HTU21D.cpp Tue Sep 05 13:18:23 2017 +0000
@@ -0,0 +1,464 @@
+/**
+ * @brief HTU21D.c
+ * @details Digital humidity sensor with temperature output.
+ * Functions file.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 4/September/2017
+ * @version 4/September/2017 The ORIGIN
+ * @pre NaN.
+ * @warning NaN
+ * @pre This code belongs to AqueronteBlog ( http://unbarquero.blogspot.com ).
+ */
+
+#include "HTU21D.h"
+
+
+HTU21D::HTU21D ( PinName sda, PinName scl, uint32_t addr, uint32_t freq )
+ : i2c ( sda, scl )
+ , HTU21D_Addr ( addr )
+{
+ i2c.frequency( freq );
+}
+
+
+HTU21D::~HTU21D()
+{
+}
+
+
+
+/**
+ * @brief HTU21D_Init ( HTU21D_master_mode_t , HTU21D_user_register_resolution_t , HTU21D_user_register_otp_t )
+ *
+ * @details It initializes the device.
+ *
+ * @param[in] myMode: Hold/No Hold master mode.
+ * @param[in] myResolution: Resolution of the sensor.
+ * @param[in] myHeater: Heater enabled or disabled.
+ *
+ * @param[out] NaN.
+ *
+ *
+ * @return Status of HTU21D_Init.
+ *
+ *
+ * @author Manuel Caballero
+ * @date 4/September/2017
+ * @version 4/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning NaN.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_Init ( HTU21D_master_mode_t myMode, HTU21D_user_register_resolution_t myResolution, HTU21D_user_register_heater_t myHeater )
+{
+ char cmd[] = { HTU21D_READ_REGISTER, 0 };
+ uint32_t aux = 0;
+
+
+ HTU21D_Mode = myMode;
+ HTU21D_Resolution = myResolution;
+
+
+ // Reserved bits must not be changed. Therefore, for any writing to user register, default values of reserved bits must be read first
+ // Datasheet: User register p.13.
+ aux = i2c.write ( HTU21D_Addr, &cmd[0], 1 );
+ aux = i2c.read ( HTU21D_Addr, &cmd[0], 1 );
+
+
+ cmd[0] &= 0x38; // Mask reserved bits
+
+ // On-chip heater
+ if ( myHeater == HEATER_ENABLED )
+ cmd[0] |= 0x04;
+
+ // Resolution
+ switch ( HTU21D_Resolution ) {
+ default:
+ case RESOLUTION_12RH_14TEMP:
+ cmd[0] &= 0x7E;
+ break;
+
+ case RESOLUTION_8RH_12TEMP:
+ cmd[0] |= 0x01;
+ break;
+
+ case RESOLUTION_10RH_13TEMP:
+ cmd[0] |= 0x80;
+ break;
+
+ case RESOLUTION_11RH_11TEMP:
+ cmd[0] |= 0x81;
+ break;
+ }
+
+
+ cmd[1] = ( cmd[0] | 0x02 ); // OTP reload disabled
+ cmd[0] = HTU21D_WRITE_REGISTER;
+
+ aux = i2c.write ( HTU21D_Addr, &cmd[0], 2 );
+
+
+
+ if ( aux == I2C_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+
+/**
+ * @brief HTU21D_SoftReset ( void )
+ * @details Rebooting the HTU21D sensor switching the power off and on again.
+ *
+ * @param[in] NaN.
+ *
+ * @param[out] Status of HTU21D_SoftReset.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning The soft reset takes less than 15ms.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_SoftReset ( void )
+{
+ char cmd = HTU21D_SOFT_RESET;
+ uint32_t aux = 0;
+
+
+ aux = i2c.write ( HTU21D_Addr, &cmd, 1 );
+ wait ( 0.015 );
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+
+ /**
+ * @brief HTU21D_TriggerTemperature ( void )
+ * @details Trigger a new temperature measurement.
+ *
+ * @param[in] NaN.
+ *
+ * @param[out] Status of HTU21D_TriggerTemperature.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning The measuring time depends on the chosen resolution.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_TriggerTemperature ( void )
+{
+ char cmd = 0;
+ uint32_t aux = 0;
+ float myDelay = 0;
+
+
+ // Check if the event is by Hold Master Mode
+ if ( HTU21D_Mode == MODE_HOLD_MASTER )
+ cmd = HTU21D_TRIGGER_TEMPERATURE_MEASUREMENT_HOLD_MASTER;
+ else
+ cmd = HTU21D_TRIGGER_TEMPERATURE_MEASUREMENT_NO_HOLD_MASTER;
+
+
+ aux = i2c.write ( HTU21D_Addr, &cmd, 1 );
+
+ // Measuring time
+ switch ( HTU21D_Resolution ){
+ default:
+ case RESOLUTION_12RH_14TEMP:
+ myDelay = 0.05;
+ break;
+
+ case RESOLUTION_8RH_12TEMP:
+ myDelay = 0.013;
+ break;
+
+ case RESOLUTION_10RH_13TEMP:
+ myDelay = 0.025;
+ break;
+
+ case RESOLUTION_11RH_11TEMP:
+ myDelay = 0.007;
+ break;
+ }
+
+ wait ( myDelay );
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+
+/**
+ * @brief HTU21D_ReadTemperature ( Vector_temperature_f* )
+ * @details Read a new temperature measurement.
+ *
+ * @param[in] mytemperature: Variable to store the temperature.
+ *
+ * @param[out] Status of HTU21D_ReadTemperature.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning HTU21D_TriggerTemperature MUST be called before.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_ReadTemperature ( Vector_temperature_f* mytemperature )
+{
+ char aux = 0;
+ char myRawTemp[] = { 0, 0, 0};
+
+
+ aux = i2c.read ( HTU21D_Addr, &myRawTemp[0], 3 );
+
+
+ mytemperature->Temperature = ( myRawTemp[0] << 8 ) | myRawTemp[1];
+ mytemperature->Temperature /= 65536.0;
+ mytemperature->Temperature *= 175.72;
+ mytemperature->Temperature -= 46.85;
+
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+
+/**
+ * @brief HTU21D_ReadRawTemperature ( Vector_raw_temperature_t* )
+ * @details Read a new raw temperature measurement.
+ *
+ * @param[in] myRawtemperature: Variable to store the temperature.
+ *
+ * @param[out] Status of HTU21D_ReadTemperature.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning HTU21D_TriggerTemperature MUST be called before.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_ReadRawTemperature ( Vector_raw_temperature_t* myRawtemperature )
+{
+ uint32_t aux = 0;
+
+
+ aux = i2c.read ( HTU21D_Addr, &myRawtemperature->RawTemperature[0], 3 );
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+/**
+ * @brief HTU21D_TriggerHumidity ( void )
+ * @details Trigger a new humidity measurement.
+ *
+ * @param[in] NaN.
+ *
+ * @param[out] Status of HTU21D_TriggerHumidity.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning The measuring time depends on the chosen resolution.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_TriggerHumidity ( void )
+{
+ char cmd = 0;
+ uint32_t aux = 0;
+ float myDelay = 0;
+
+
+ // Check if the event is by Hold Master Mode
+ if ( HTU21D_Mode == MODE_HOLD_MASTER )
+ cmd = HTU21D_TRIGGER_HUMIDITY_MEASUREMENT_HOLD_MASTER;
+ else
+ cmd = HTU21D_TRIGGER_HUMIDITY_MEASUREMENT_NO_HOLD_MASTER;
+
+
+ aux = i2c.write ( HTU21D_Addr, &cmd, 1 );
+
+ // Measuring time
+ switch ( HTU21D_Resolution ){
+ default:
+ case RESOLUTION_12RH_14TEMP:
+ myDelay = 0.05;
+ break;
+
+ case RESOLUTION_8RH_12TEMP:
+ myDelay = 0.013;
+ break;
+
+ case RESOLUTION_10RH_13TEMP:
+ myDelay = 0.025;
+ break;
+
+ case RESOLUTION_11RH_11TEMP:
+ myDelay = 0.007;
+ break;
+ }
+
+ wait ( myDelay );
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+
+/**
+ * @brief HTU21D_ReadHumidity ( Vector_humidity_f* )
+ * @details Read a new humidity measurement.
+ *
+ * @param[in] myhumidity: Variable to store the humidity.
+ *
+ * @param[out] Status of HTU21D_ReadHumidity.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning HTU21D_TriggerHumidity MUST be called before.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_ReadHumidity ( Vector_humidity_f* myhumidity )
+{
+ uint32_t aux = 0;
+ char myRawRH[] = { 0, 0, 0};
+
+
+ aux = i2c.read ( HTU21D_Addr, &myRawRH[0], 3 );
+
+
+ myhumidity->Humidity = ( myRawRH[0] << 8 ) | myRawRH[1];
+ myhumidity->Humidity /= 65536.0;
+ myhumidity->Humidity *= 125.0;
+ myhumidity->Humidity -= 6.0;
+
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+
+/**
+ * @brief HTU21D_ReadRawHumidity ( Vector_raw_humidity_t* )
+ * @details Read a new raw humidity measurement.
+ *
+ * @param[in] myRawhumidity: Variable to store the raw humidity.
+ *
+ * @param[out] Status of HTU21D_ReadHumidity.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning The measuring time depends on the chosen resolution.
+ * @warning HTU21D_TriggerHumidity MUST be called before.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_ReadRawHumidity ( Vector_raw_humidity_t* myRawhumidity )
+{
+ uint32_t aux = 0;
+
+
+ aux = i2c.read ( HTU21D_Addr, &myRawhumidity->RawHumidity[0], 3 );
+
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
+
+
+
+/**
+ * @brief HTU21D_BatteryStatus ( HTU21D_user_register_status_t* )
+ * @details Read the user register to check the battery status.
+ *
+ * @param[in] battStatus: Variable to store the battery status.
+ *
+ * @param[out] Status of HTU21D_BatteryStatus.
+ *
+ *
+ * @return NA
+ *
+ * @author Manuel Caballero
+ * @date 5/September/2017
+ * @version 5/September/2017 The ORIGIN
+ * @pre NaN
+ * @warning NaN.
+ */
+HTU21D::HTU21D_status_t HTU21D::HTU21D_BatteryStatus ( HTU21D_user_register_status_t* battStatus )
+{
+ char cmd = HTU21D_READ_REGISTER;
+ uint32_t aux = 0;
+
+
+ aux = i2c.write ( HTU21D_Addr, &cmd, 1 );
+ aux = i2c.read ( HTU21D_Addr, &cmd, 1 );
+
+
+ cmd &= 0x40; // Mask 'Status: End of Batter' bit
+
+ if ( cmd == 0x40 )
+ *battStatus = STATUS_END_BATTERY_LOW_2V25;
+ else
+ *battStatus = STATUS_END_BATTERY_HIGH_2V25;
+
+
+ if ( aux == HTU21D_SUCCESS )
+ return HTU21D_SUCCESS;
+ else
+ return HTU21D_FAILURE;
+}
--- a/HTU21D.h Thu Aug 31 20:28:28 2017 +0000
+++ b/HTU21D.h Tue Sep 05 13:18:23 2017 +0000
@@ -25,7 +25,7 @@
#include "mbed.h"
#include "HTU21D.h"
-HTU21D myBarometricSensor ( I2C_SDA, I2C_SCL, HTU21D::HTU21D_ADDRESS, 400000 );
+HTU21D myTempRXSensor ( I2C_SDA, I2C_SCL, HTU21D::HTU21D_ADDRESS, 400000 );
Serial pc ( USBTX, USBRX ); // tx, rx
@@ -33,46 +33,37 @@
DigitalOut myled(LED1);
-HTU21D::Vector_cal_coeff_t myCalCoeff;
-HTU21D::Vector_temp_f myUT;
-HTU21D::Vector_pressure_f myUP;
-HTU21D::Vector_compensated_data_f myTrueData;
+HTU21D::Vector_temperature_f myTemperature;
+HTU21D::Vector_humidity_f myHumidity;
-uint32_t myState = 0;
+
void sendDATA ( void )
{
- switch ( myState ) {
- case 0:
- // Trigger a new temperature measurement
- myBarometricSensor.HTU21D_TriggerTemperature ();
- myState = 1;
- break;
-
- case 1:
- // Read the uncompensated temperature data and trigger a new pressure measurement
- myBarometricSensor.HTU21D_ReadRawTemperature ( &myUT );
- myBarometricSensor.HTU21D_TriggerPressure ( HTU21D::PRESSURE_STANDARD_MODE );
- myState = 2;
- break;
-
- case 2:
- // Read the uncompensated pressure data, calculate the compensated temperature and pressure and send it through the UART
- myled = 1;
- myBarometricSensor.HTU21D_ReadRawPressure ( &myUP );
-
- myTrueData = myBarometricSensor.HTU21D_CalculateCompensated_Temperature_Pressure ( myCalCoeff, myUT, myUP, HTU21D::PRESSURE_STANDARD_MODE );
-
- pc.printf( "Temperature: %0.1f\nPressure: %ld\r\n", ( float )myTrueData.Temperature/10, myTrueData.Pressure );
- myled = 0;
- myState = 0;
- break;
-
- default:
- myState = 0;
- break;
- }
-
+ HTU21D::HTU21D_user_register_status_t myBatteryStatus;
+
+ myled = 1;
+
+ // Get Temperature
+ myTempRXSensor.HTU21D_TriggerTemperature ();
+ myTempRXSensor.HTU21D_ReadTemperature ( &myTemperature );
+
+ // Get Humidity
+ myTempRXSensor.HTU21D_TriggerHumidity ();
+ myTempRXSensor.HTU21D_ReadHumidity ( &myHumidity );
+
+ // Get Battery Status
+ myTempRXSensor.HTU21D_BatteryStatus ( &myBatteryStatus );
+
+ // Send data through the UART
+ pc.printf( "\nTemperature: %0.01f\nHumidity: %0.01f\n", myTemperature.Temperature, myHumidity.Humidity );
+
+ if ( myBatteryStatus == HTU21D::STATUS_END_BATTERY_HIGH_2V25 )
+ pc.printf( "Battery status higher than 2.25V\r\n" );
+ else
+ pc.printf( "Battery status lower than 2.25V\r\n" );
+
+ myled = 0;
}
@@ -80,12 +71,8 @@
{
pc.baud ( 115200 );
- myBarometricSensor.HTU21D_GetCalibrationCoefficients ( &myCalCoeff );
-
- // Print the calibration coefficients
- pc.printf( "AC1: %ld\nAC2: %ld\nAC3: %ld\nAC4: %ld\nAC5: %ld\nAC6: %ld\nB1: %ld\nB2: %ld\nMB: %ld\nMC: %ld\nMD: %ld\r\n",
- myCalCoeff.AC1, myCalCoeff.AC2, myCalCoeff.AC3, myCalCoeff.AC4, myCalCoeff.AC5, myCalCoeff.AC6, myCalCoeff.B1,
- myCalCoeff.B2, myCalCoeff.MB, myCalCoeff.MC, myCalCoeff.MD );
+ myTempRXSensor.HTU21D_SoftReset ();
+ myTempRXSensor.HTU21D_Init ( HTU21D::MODE_NO_HOLD_MASTER, HTU21D::RESOLUTION_12RH_14TEMP, HTU21D::HEATER_DISABLED );
serial.attach( &sendDATA, 1 ); // the address of the function to be attached ( sendDATA ) and the interval ( 1s )
@@ -175,11 +162,11 @@
#ifndef VECTOR_STRUCT_H
#define VECTOR_STRUCT_H
typedef struct {
- uint8_t RawTemperature[3];
+ char RawTemperature[3];
} Vector_raw_temperature_t;
typedef struct {
- uint8_t RawHumidity[3];
+ char RawHumidity[3];
} Vector_raw_humidity_t;
typedef struct {
@@ -219,7 +206,7 @@
/** It configures the device.
*/
- HTU21D_status_t HTU21D_Init ( HTU21D_master_mode_t myMode, HTU21D_user_register_resolution_t myResolution, HTU21D_user_register_otp_t myHeater );
+ HTU21D_status_t HTU21D_Init ( HTU21D_master_mode_t myMode, HTU21D_user_register_resolution_t myResolution, HTU21D_user_register_heater_t myHeater );
/** It resets the device by software.
*/