Example temperature sensor interface. More...

#include <stdbool.h>
#include <stdint.h>

Include dependency graph for temperature_sensor.h:

Classes
struct	TemperatureSensor
	Virtual Temperature Sensor Interface. More...

struct	TemperatureSensor_withCb
	Virtual Temperature Sensor Interface with Callback Support. More...

Typedefs
typedef void(*	NewTemperatureSampleCb) (int16_t temperature)
	Callback function prototype for processing new temperature samples. More...

typedef void(*	TemperatureErrorCb) (void)
	Callback function prototype for temperature sensor errors. More...

Detailed Description

Example temperature sensor interface.

This header defines the core interfaces for a virtual temperature sensor. Two samples are provided:

A basic interface for reading temperature (TemperatureSensor)
An interface expanded with support for callbacks (TemperatureSensor_withCb)

Modifying the Interfaces

There are a number of ways you might modify this interface to suit your needs:

Change the type or format of the temperature value
Return the temperature sample, and use a separate function to determine validity
Supporting a purely asynchronous processing model (see barometric_sensor.h or asynchronous_interface.h for an example)

Possible Humidity Specifications

For the data format, we can consider a few options:

floating point
Provide a signed 16-bit fixed point integer in format Q7.8 (1 sign bit, 7 integral bits, and 8 fractional bits). This gives us a range of [-128°C, 128°C] (well beyond the ranges typically supported by temperature sensors, and beyond the needs of our intended application). We end up with a resolution of 0.0039°C.
Q8.7 would provide a greater range (±256°C) with still-more-than-sufficient precision (0.0078°C). However, this is still well beyond the temperature range of sensors we work with.
If higher resolution as important (or 32-bit values are preferred for processing reasons), providing a 32-bit fixed point integer with format Q21.10, gives a resolution of 0.001°C.
Use a standard of Q16 to simplify fixed point math across your entire system

Definition in file temperature_sensor.h.

Typedef Documentation

◆ NewTemperatureSampleCb

typedef void(* NewTemperatureSampleCb) (int16_t temperature)

Callback function prototype for processing new temperature samples.

When a new (and valid) temperature 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] temperature The latest temperature sample.

Temperature readings will be provided as a signed 16-bit fixed point integer in format Q7.8.

Definition at line 98 of file temperature_sensor.h.

◆ TemperatureErrorCb

typedef void(* TemperatureErrorCb) (void)

Callback function prototype for temperature sensor errors.

When an error in the virtual temperature 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.).