Example barometric pressure sensor interfaces that also support altitude calculations. More...
#include <stdbool.h>#include <stdint.h>
Go to the source code of this file.
Classes | |
| struct | BarometricSensor |
| Virtual Barometric Pressure/Altimeter Sensor Interface. More... | |
| struct | BarometricSensor_withCb |
| Virtual Barometric Pressure/Altimeter Interface (with callback support) More... | |
| struct | BarometricSensor_asyncWithCb |
| Virtual Barometric Pressure/Altimeter Interface (asynchronous mode) More... | |
Typedefs | |
| typedef void(* | NewBarometricSampleCb) (uint32_t pressure, int32_t altitude) |
| Callback function prototype for processing new barometric samples. More... | |
| typedef void(* | BarometricErrorCb) (void) |
| Callback function prototype for barometric sensor errors. More... | |
Detailed Description
Example barometric pressure sensor interfaces that also support altitude calculations.
This header defines three variations of a barometric sensor:
- A simple interface, which only provides the capabilities of reading pressure/altitude (BarometricSensor).
- A variation which supports callbacks (BarometricSensor_withCb).
- A variation that supports callbacks and expects to be used in an asynchronous system (BarometricSensor_asyncWithCb).
Note that there are differences in fundamental assumptions and function behaviors across the variations. Even small changes in an interface can impact expected behaviors.
Modifying the Interfaces
There are a number of ways you might modify this interface to suit your needs:
- Change the type of the pressure parameter (e.g., to a float)
- Change the fixed-point format of the parameter (e.g., to 24.8, giving a wider range reduced resolution. Or adopt a standard like Q16 across all values in your program so you can simplify math operations)
- Return the pressure sample, and use a separate function to determine validity.
- Specifying additional callback parameters
- Varying the types of callbacks used
- Separating callbacks for altitude and pressure updates
- Eliminating the ability to unregister a callback
- Supporting only a single callback function (this is primarily a change in documentation to note the change in assumption)
Definition in file barometric_sensor.h.
Typedef Documentation
◆ BarometricErrorCb
| typedef void(* BarometricErrorCb) (void) |
Callback function prototype for barometric sensor errors.
When an error in the virtual barometric device occurs, this callback function will be invoked. The virtual device itself does not support error handling capabilities, so we recommend using this callback in tightly-coupled system code to take the appropriate recovery action (restart the device, restart the system, etc.).
The callback is not guaranteed to run on its own thread of control. We recommend keeping the implementation small. Your function implementation could take the new sample and perform some dispatching operation (e.g., add the value to a queue), ensuring that any "heavy" processing happens on a new thread.
Definition at line 151 of file barometric_sensor.h.
◆ NewBarometricSampleCb
| typedef void(* NewBarometricSampleCb) (uint32_t pressure, int32_t altitude) |
Callback function prototype for processing new barometric samples.
When a new (and valid) barometric pressure/altitude sample is available, this callback function will be invoked.
The callback is not guaranteed to run on its own thread of control. We recommend keeping the implementation small. Your function implementation could take the new sample and perform some dispatching operation (e.g., add the value to a queue), ensuring that any "heavy" processing happens on a new thread.
- Parameters
-
[in] pressure The latest pressure sample.
Pressure will be formatted as a 32-bit fixed-point integer with format UQ22.10, giving a resolution of 0.001 hPa.
- Parameters
-
[in] altitude The latest altitude sample.
Altitude will be formatted as a signed 32-bit fixed-point number in format Q21.10.
Definition at line 136 of file barometric_sensor.h.
