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https://github.com/sensirion/embedded-i2c-svm4x

Generic embedded C driver to work with the Sensirion's SVM41 sensor modules via I2C
https://github.com/sensirion/embedded-i2c-svm4x

driver embedded evaluation-kit humidity i2c nox sek sensirion svm41 svm4x temperature voc

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Generic embedded C driver to work with the Sensirion's SVM41 sensor modules via I2C

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README 

        
# Sensirion Embedded I2C SVM4x Driver



This is a generic embedded driver for the [Sensirion SVM4x Evaluation Kit](https://www.sensirion.com/my-sgp-ek/).

It enables developers to communicate with the SVM4x evaluation kit on different hardware platforms by only adapting the I2C communication related source files.



The SVM4x evaluation kit covers evaluation of the SGP40 and SGP41 sensors.






# Getting started



## Implement the I2C Interface



So we need to adjust two files according to your platform.



### Edit `sensirion_i2c_hal.c`



This file contains the implementation of the sensor communication, which

depends on your hardware platform. We provide function stubs for your

hardware's own implementation.

Sample implementations are available for some platforms:

[`sample-implementations`](sample-implementations). For Linux based platforms

like Raspberry Pi you can just replace the unimplemented HAL template with the

implementation in `sample-implementations/linux_user_space/`:



```

cp sample-implementations/linux_user_space/sensirion_i2c_hal.c ./

```



### Edit `sensirion_config.h`



Skip this part for Linux based platforms since everything is already setup for

this case.



Otherwise you need to check if the libraries `` and `` are

provided by your toolchain, compiler or system. If you have no idea on how to

do that you can skip this step for now and come back when you get errors

related to these names when compiling the driver.

The features we use from those libraries are type definitions for integer sizes

from `` and `NULL` from ``. If they are not available you

need to specify the following integer types yourself:



* `int64_t` = signed 64bit integer

* `uint64_t` = unsigned 64bit integer

* `int32_t` = signed 32bit integer

* `uint32_t` = unsigned 32bit integer

* `int16_t` = signed 16bit integer

* `uint16_t` = unsigned 16bit integer

* `int8_t` = signed 8bit integer

* `uint8_t` = unsigned 8bit integer



In addition to that you will need to specify `NULL`. For both we have a

detailed template where you just need to fill in your system specific values.



Now we are ready to compile and run the example usage for your sensor.



## Compile and Run



Pass the source `.c` and header `.h` files in this folder into your C compiler

and run the resulting binary. This step may vary, depending on your platform.

Here we demonstrate the procedure for Linux based platforms:



1. Open up a terminal.

2. Navigate to the directory where this README is located.

3. Run `make` (this compiles the example code into one executable binary).

4. Run the compiled executable with `./svm41_i2c_example_usage`

5. Now you should see the first measurement values appear in your terminal. As

   a next step you can adjust the example usage file or write your own main

   function to use the sensor.



# Background



## Files



### sensirion\_i2c.[ch]



In these files you can find the implementation of the I2C protocol used by

Sensirion sensors. The functions in these files are used by the embedded driver

to build the correct frame out of data to be sent to the sensor or receive a

frame of data from the sensor and convert it back to data readable by your

machine. The functions in here calculate and check CRCs, reorder bytes for

different byte orders and build the correct formatted frame for your sensor.



### sensirion\_i2c\_hal.[ch]



These files contain the implementation of the hardware abstraction layer used

by Sensirion's I2C embedded drivers. This part of the code is specific to the

underlying hardware platform. This is an unimplemented template for the user to

implement. In the `sample-implementations/` folder we provide implementations

for the most common platforms.



### sensirion\_config.h



In this file we keep all the included libraries for our drivers and global

defines. Next to `sensirion_i2c_hal.c` *it's the only file you should need to

edit to get your driver working.*



### sensirion\_common.[ch]



In these files you can find some helper functions used by Sensirion's embedded

drivers. It mostly contains byte order conversions for different variable

types. These functions are also used by the UART embedded drivers therefore

they are kept in their own file.