Würth eiSos Series User manual

SENSORS SOFTWARE DEVELOPMENT KIT
USER MANUAL
VERSION 1.1
OCTOBER 31, 2019

Revision history
Manual
version
SW
version Notes Date
1.0 1.0 • Initial version of this document August 2019
1.1 1.1
• Updated sensors supported and
software history
• Changed the wiringPi install
method as recommended by it’s
author.
November 2019
?For SDK version history see chapter Software history
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Version 1.1 © October 2019
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Abbreviations and abstract
Abbreviation Name Description
ADC Analog to Digital converter
ASIC Application specific
integrated circuit
GPIO General Purpose Input
Output
IDE Integrated development
environment A set of tools for software development
I2C Inter-integrated circuit Serial communication interface and
protocol
MCU Microcontroller
SDK Software development kit Software development tool to integrate
various Würth Elektronik eiSos products
SPI Serial peripheral interface Serial communication interface and
protocol
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Contents
1 Introduction 4
1.1 Motivation..................................... 4
2 Sensors SDK overview 6
2.1 Platform-independent sensor drivers . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Sampleapplications ............................... 6
2.3 Contents of the Sensors SDK . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Host integration 8
4 Running Sensors SDK sample application on the Raspberry Pi 10
4.1 Hardwareconnections.............................. 10
4.2 Install the Raspbian OS on the Raspberry Pi . . . . . . . . . . . . . . . . . 12
4.2.1 Configuring the peripherals . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Install the wiringPi library . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.4 Install the Sensors SDK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5 Software history 16
6 Important notes 17
6.1 General customer responsibility . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.2 Customer responsibility related to specific, in particular safety-relevant ap-
plications ..................................... 17
6.3 Best care and attention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.4 Customer support for product specifications . . . . . . . . . . . . . . . . . . 17
6.5 Productimprovements.............................. 18
6.6 Productlifecycle ................................. 18
6.7 Propertyrights .................................. 18
6.8 General terms and conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7 Legal notice 19
7.1 Exclusionofliability................................ 19
7.2 Suitability in customer applications . . . . . . . . . . . . . . . . . . . . . . . 19
7.3 Usagerestriction ................................. 19
8 License terms for Würth Elektronik eiSos GmbH & Co. KG sensor product
software and source code 21
8.1 Limitedlicense .................................. 21
8.2 Usageandobligations .............................. 21
8.3 Ownership..................................... 22
8.4 Disclaimerofwarranty .............................. 22
8.5 Limitationofliability................................ 22
8.6 Applicable law and jurisdiction . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.7 Severabilityclause ................................ 23
8.8 Miscellaneous................................... 23
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1 Introduction
The Würth Elektronik eiSos range of sensors provide advanced sensing capabilities to any
embedded application. The built-in digital interface enables easy integration with any of the
most commonly used host MCUs through industry standard serial communication interfaces
like I2C. This also allows complete configuration and control of the sensor via software run-
ning on the host MCU.
The Sensors SDK is a set of software tools that enable quick software integration of Würth
Elektronik eiSos sensors to application software on the host MCU. It consists of a set of
platform-independent drivers for the sensors and sample applications developed on the
Raspberry Pi platform written in C.
1.1 Motivation
A typical sensor from Würth Elektronik eiSos consists of the sensing element along with an
ASIC which implements the control logic. All configurations of the sensors are done by writ-
ing specific values to a set of control registers on board. One or more status registers can be
monitored to get the current status of the sensor and finally, the output is stored in the output
registers. These sensors not only deliver the raw values of the physical parameter being
sensed, but also perform several advanced functions like filtering, FIFO-storage, threshold
detection, interrupt generation etc.
To use the complete feature set of such a sensor, control of all the necessary registers have
to be implemented on the host MCU. This involves considerable effort for the user. The aim
of the Sensors SDK is to minimize the effort required to integrate the sensor control software
to the host application.
It contains the implementations of all the available functions of the sensors in pure C-code.
In order to integrate any Würth Elektronik eiSos sensor to the application, the user has to
simply port the corresponding C-code to his host MCU. This significantly reduces the time
needed for developing the software interface to the sensor.
The steps for porting are explained in more detail in chapter 3 .
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Figure 1: Sensors SDK driver as part of the end product
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2 Sensors SDK overview
In this chapter, constituents of the Sensors SDK are described in details.
2.1 Platform-independent sensor drivers
This part of the Sensors SDK consists of a set of C header and source file per sensor.
Every source file contains implementations for configuration and control of the sensors that
is exposed to the application via functions and type declarations in the corresponding header
file. Being platform independent and written in C enables easy porting of the drivers to any
custom MCU platform.
2.2 Sample applications
In order to kick-start the application development, several sample applications that includes
typical use-cases of the sensors are made available as a part of the Sensors SDK. These
examples are developed on the Raspberry Pi platform. The Sensors SDK contains the com-
plete source code for all the sample applications including the project files for the Code::Blocks
IDE.
The sample applications were tested on Raspberry Pi 3 Model B with Raspbian
Stretch and Raspberry Pi 3 Model B+ with Raspbian Buster. Code::Blocks
version 17.12 was used as the IDE
These sample applications allow the user to take the sensor into operation. Additionally, the
availability of the source code allows the user to try out several configurations and decide on
the ones suitable for the application with minimal effort.
The sensors supported by the different versions of the Sensors SDK are shown in table 1 .
SDK version Sensor Sensor type
1.0, 1.1 WSEN-PADS
(2511020213301) Absolute pressure sensor
1.1 WSEN-ITDS
(2533020201601) Acceleration sensor
1.1 WSEN-PDUS
(25131308XXX01) Differential pressure sensors
Table 1: Sensor support in the Sensors SDK
The Differential pressure sensors with matchcode WSEN-PDUS work with 5V
logic and should not be directly connected to Raspberry Pi. Hence, no sample
applications (example directory) for this sensors are currently implemented for
the Raspberry Pi platform.
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2.3 Contents of the Sensors SDK
The Sensors SDK is delivered as a compressed zip-file. All code related to a sensor sup-
ported by the Sensors SDK are placed under a sub directory named after the corresponding
sensor.
Each sensor directory contains two sub-directories, drivers and examples. The sub-directory
drivers contains the platform-independent code that can be used to port to the custom MCU.
The examples folder contains sample applications that run on the Raspberry-Pi. The sub-
directory platform contains the platform-specific implementation for the Raspberry-Pi.
The current version of the Sensors SDK is specified in the version.h file.
/platform ................................
Platform specic code for the Raspberry Pi
platform.c
platform.h
version.h ................................................. Sensors SDK version le
...
WSEN_PADS_2511020213301 ..... Contains all the code related to sensor 2511020213301
drivers ....................................... Code to be ported to custom hosts
WSEN_PADS_2511020213301.h .................... Function and type declarations
WSEN_PADS_2511020213301.c ........ Implementation of the sensor functionality
examples ....................................... Sample application WSEN-PADS
...
quickStart ............................................... Quick start example
main.c
quickStart.cbp
...
WSEN_ITDS_2533020201601 ..... Contains all the code related to sensor 2533020201601
drivers ....................................... Code to be ported to custom hosts
WSEN_ITDS_2533020201601.h .................... Function and type declarations
WSEN_ITDS_2533020201601.c ........ Implementation of the sensor functionality
examples ....................................... Sample application WSEN-ITDS
...
quickStart ............................................... Quick start example
main.c
quickStart.cbp
...
...
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3 Host integration
As described in chapter 2 the Sensors SDK has a platform independent driver component
and Raspberry-pi specific examples which demonstrate the use of these drivers. In the fol-
lowing, the steps involved in porting the drivers to a custom platform is described.
The contents of the drivers directory has to be directly integrated into the custom project.
For example, in case of WSEN_PADS, include the WSEN_PADS_2511020213301.h and
WSEN_PADS_2511020213301.c files to the custom project.
The file platform.h declares platform specific functions that has to be implemented by the
user on the custom host. For example, the access to I2C interface of the host is declared
with the following functions.
/* *
*@brief Initialize the I2C Interface
*@param I2C address
*@retval Error Code
*/
int8_t I2CInit (int address);
/* *
*@brief Read data starting from the addressed register
*@param −RegAdr : the register address to read from
*−NumByteToRead : number of bytes to read
*−pointer Data : the address store the data
*@retval Error Code
int8_t ReadReg(uint8_t RegAdr, int NumByteToRead, uint8_t *Data);
/**
*@brief Write data strarting from the addressed register
*@param −RegAdr : Address to write in
*−NumByteToWrite : number of bytes to write
*−pointer Data : Address of the data to be written
*@retval Error Code
*/
int8_t WriteReg(int RegAdr, int NumByteToWrite, uint8_t *Data);
Code 1: Code snippet for I2C interface
Here the definition of these functions, depending on the host peripherals, has to be imple-
mented by the user. The function I2CInit() should initialize the I2C peripheral on the custom
MCU and the functions ReadReg() and WriteReg() should enable reading/writing data bytes
over the I2C bus.
Please refer to the user manual of the corresponding sensor for a detailed
description of the characteristics of the digital interface being used.
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The register read and write functions shall be implemented to read/write one
byte at a time. Burst read/write operations can be implemented based on the
host MCU peripheral and the sensor used.
The existing platform.c file, can be removed from the project as it contains the correspond-
ing implementation for the Raspberry Pi.
On porting the aforementioned functions onto the custom MCU, the driver can be used
seamlessly for the application development. The sample applications can be used as a
starting point for further development.
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