Quick start guide for HIH8120 Temperature and Humidity Driver

This is the quick start guide for the HIH8120 Temperature and Humidity Driver, with step-by-step instructions on how to configure and use the driver in a selection of use cases.

The use cases contain several code fragments. The code fragments in the steps for setup can be copied into a custom initialization function, while the steps for usage can be copied into, e.g., the main application function.

HIH8120 Driver use cases

• Initialise the driver
• How to perform a new measuring with the sensor

Initialise the driver

The following must be added to the project:

• #include <hih8120.h>

Add to application initialization:

• Initialise the driver:

  if ( HIH8120_OK == hih8120_initialise() )
  {
         // Driver initialised OK
         // Always check what hih8120_initialise() returns
  }

Note

If used from FreeRTOS: The driver must be initialised hih8120_initialise before the FreeRTOS sheduler is started!!

How to perform a new measuring with the sensor

In this use case, the steps to perform a measuring is shown.

Note

The driver must be initialised Initialise the driver before a measuring is possible.

In this example these two variables will be used to store the results in

float humidity = 0.0;
float temperature = 0.0;

Perform the measuring

The following must be added to the application code and executed for each new measuring:

1. Wake up the sensor from power down:

   if ( HIH8120_OK != hih8120_wakeup() )
   {
          // Something went wrong
          // Investigate the return code further
   }

   Note

   After the hih8120_wakeup() call the sensor will need minimum 50 ms to be ready!

2. Poll the sensor for the results:

   if ( HIH8120_OK !=  hih8120_measure() )
   {
          // Something went wrong
          // Investigate the return code further
   }

   Note

   After the hih8120_measure() call the two wire inteface (TWI) will need minimum 1 ms to fetch the results from the sensor!
   

3. Get the results: The result can now be retrieved by calling one of these methods hih8120_getHumidityPercent_x10(), hih8120_getTemperature_x10(), hih8120_getHumidity() or hih8120_getTemperature().

A small example

humidity = hih8120_getHumidity();
temperature = hih8120_getTemperature();