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https://github.com/sensirion/embedded-i2c-scd30

Sensirion I2C driver for embedded platforms for sensor SCD30
https://github.com/sensirion/embedded-i2c-scd30

co2 co2-sensor driver embedded humidity i2c sensirion temperature

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Sensirion I2C driver for embedded platforms for sensor SCD30

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README 

        
# Sensirion I2C SCD30 embedded Library



This document explains how to set up a  SCD30 sensor to run on a embedded device

using the provided code.






Click [here](https://sensirion.com/products/catalog/SCD30/) to learn more about the Sensirion SCD30 sensor.



The default I²C address of [SCD30](https://sensirion.com/products/catalog/SCD30/) is **0x61**.



## Setup Guide



### Connecting the Sensor



Your sensor has 5 different signals that need to be connected to your board: VDD, GND, SCL, SDA, SEL.

Use the following pins to connect your SCD30:






| *Pin* | *Cable Color* | *Name* | *Description*  | *Comments* |

|-------|---------------|:------:|----------------|------------|

| 1 | red |VDD | Supply Voltage | 3.3 to 5.5V

| 2 | black |GND | Ground | 

| 3 | yellow |SCL | I2C: Serial clock input | 

| 4 | green |SDA | I2C: Serial data input / output | 

| 5 |  |RDY | High when data is available | do not connect

| 6 |  |PWM |  | do not connect

| 7 | blue |SEL | Interface select | Pull to ground or floating for I2C



The recommended voltage is 3.3V.



### Configure the code



In order to use the provided code 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 `./scd30_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.



## Contributing



**Contributions are welcome!**



We develop and test this driver using our company internal tools (version

control, continuous integration, code review etc.) and automatically

synchronize the master branch with GitHub. But this doesn't mean that we don't

respond to issues or don't accept pull requests on GitHub. In fact, you're very

welcome to open issues or create pull requests :)



This Sensirion library uses

[`clang-format`](https://releases.llvm.org/download.html) to standardize the

formatting of all our `.c` and `.h` files. Make sure your contributions are

formatted accordingly:



The `-i` flag will apply the format changes to the files listed.



```bash

clang-format -i *.c *.h

```



Note that differences from this formatting will result in a failed build until

they are fixed.



# License



See [LICENSE](LICENSE).