ST STEVAL-STWINKT1 User manual

Introduction

Cellular low power wide area network (LPWAN) technologies are highly applicable in Industrial Internet of Things (IIoT)

scenarios, especially those involving battery-powered sensor nodes that require wireless, low power and long-range

connectivity. Condition monitoring and predictive maintenance applications can take advantage of LPWAN protocols such as

NB-IoT and LTE-M to deliver affordable cloud monitoring solutions for industrial equipment when wired connectivity is not viable.

Narrow band Internet of Things (NB-IoT) is a standards-based, LPWAN technology that offers a wide range of services

associated with connected objects. It can significantly reduce power consumption in user devices and still provide the necessary

coverage for application control and data transmission services, including security and privacy support for user identity

confidentiality, entity authentication, confidentiality, data integrity, and mobile equipment identification.

Long-term evolution machine type communication (LTE-M) offers better performance and can therefore complement NB-IoT

when high data transmission speeds and terminal mobility are required, while the superior radioelectric coverage, lower costs

and longer battery life offered by NB-IoT should be preferred when these services are not necessary.

The STSW-STWINCELL software package lets you test and develop a smart industrial condition monitoring sensor node

connected to a cloud application based on Amazon Web Services (AWS) over innovative LPWAN cellular technologies such as

NB-IoT and LTE-M. The firmware runs on the SensorTile Wireless Industrial Node (STEVAL-STWINKT1) along with the STMod

+ cellular expansion board with BG96 modem from Quectel (included in the P-L496G-CELL02 Discovery pack).

Figure 1. ST Predictive Maintenance scenario using cellular networks

This cellular connectivity allows the STSW-STWINCELL firmware to publish smart, prepocessed data from STEVAL-STWINKT1

sensor nodes on the ST Predictive Maintenance Dashboard (DSH-PREDMNT) cloud application based on Amazon Web

Services (AWS), from which you can gather, monitor and analyze critical vibration, ultrasound and environmental data on

specific industrial equipment.

RELATED LINKS

Use Google Chrome to run the Predictive Maintenance Dashboard with your myST login credentials

How to work with LPWAN cellular connectivity on STEVAL-STWINKT1 for cloud

condition-based monitoring applications

AN5472

AN5472 - Rev 1 - March 2020

For further information contact your local STMicroelectronics sales office.

www.st.com

1Hardware and software requirements

Figure 2. STEVAL-STWINKT1 with STMOD+ cellular add-on board

1.1 Hardware requirements

1. STEVAL-STWINKT1 STWIN SensorTile Wireless Industrial Node development kit

–Core system board with industrial-grade sensors and ultra-low-power MCU

– Li-Po battery 480 mAh

–STLINK-V3MINI debugger with programming cable

– Plastic box

2. Cellular STMod+ expansion board with Quectel BG96 worldwide cellular modem (LTE Cat M1/Cat NB1/

EGPRS module).

Note: The expansion board is not available separately and can only be ordered as part of the P-L496G-CELL02

STM32 Discovery pack, which includes a Discovery MCU board that you can use to optimize the scanning and

connection times of the BG96 modem on the cellular expansion board.

3. Micro-SIM (3FF) with M2M/NB-IoT profile

4. Windows PC

RELATED LINKS

7 Optimizing modem scanning and connection times on page 37

1.2 Software requirements

1. STSW-STWINCELL cellular to cloud connectivity software package.

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Hardware and software requirements

AN5472 - Rev 1 page 2/48

2. X-CUBE-CELLULAR cellular connectivity software expansion for STM32Cube.

Note: This software is optional and can be used to optimize the scanning and connection times of the BG96 modem

on the cellular expansion board.

3. Quectel LTE&5G Windows USB Driver. This software is optional and offers an alternative way to optimize

the BG96 module scanning and connection times.

4. STM32CubeProg, an all-in-one multi-OS software tool for programming STM32 products, to erase and

program the flash memory of the microcontroller

5. IDE for STM32 to rebuild the projects

–IAR Embedded Workbench V8.32.3

–Keil MDK-ARM V5.27.1

–STM32CubeIDE V1.2.0

6. Terminal emulator program (e.g. Tera Term)

7. DSH-PREDMNT Predictive Maintenance Dashboard AWS cloud application

RELATED LINKS

Use Google Chrome to run the Predictive Maintenance Dashboard with your myST login credentials

7 Optimizing modem scanning and connection times on page 37

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Software requirements

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2Firmware

2.1 Architecture

The STSW-STWINCELL software package is a set of libraries and embedded software blocks available to enable

fast and easy development on the STM32 platform.

Figure 3. STSW-STWINCELL firmware architecture

Application

level

PREDMNT AWS

via Cellular to Cloud

Utilities

Middleware

level

Cellular framework

Cellular service COM

AT framework

IPC

FreeRTOSTM Motion

Signal

Processing

AWS

CMSIS

Drivers

Development

boards STEVAL-STWINKT1

PC software

Hardware

components

Sensors

HTS221

LPS22HH

IIS3DWB

Cellular ModulesMCU

STM32L4R9ZI

User interfaces

and utilities

MP23ABS1

Predictive Maintenance

AWS Dashboard

Board Support Package

(BSP)

Hardware Abstraction

Layer (HAL)

Quectel BG96

LTE Cat M1 & Cat NB1 &

EGPRS Module

STMod+ cellular expansion board

(BG96)

• Board Support Package (BSP): set of APIs related to the hardware components on the boards.

• Hardware abstraction layer (HAL): low-level drivers and the hardware interfacing methods to interact with the

upper layers.

• Cortex Microcontroller Software Interface Standard (CMSIS): enables consistent device support and simple

software interfaces to the processor and its peripherals.

•Middleware components: set of libraries for specific algorithms, communication interface and real time

operating system.

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Firmware

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2.2 Folder structure

STSW-STWINCELL This software package is developed using the standard STM32Cube framework structure

shown below:

\STSW-STWINCELL

├───_htmresc

├───Documentation

├───Drivers

├───Middlewares

├───Projects

└───Utilities

_htmresc This folder contains the html resources.

Documentation This folder contains the documentation.

Drivers This folder contains the following main groups:

├───Drivers

│ ├───BSP

│ ├───CMSIS

│ └───STM32L4xx_HAL_Driver

BSP The board specific drivers for whole the HW components. The BSP files are grouped in

folders that include all the hardware device low level drivers as well as all specific

board medium level drivers.

│ ├───BSP

│ │ ├───Components

│ │ ├───Modems

│ │ └───STWIN

Components The Components folder includes a set of platform-independent device drivers and

their common files.

│ │ ├───Components

│ │ │ ├───Common

│ │ │ ├───hts221

│ │ │ ├───iis3dwb

│ │ │ └───lps22hh

Modems The Modems folder includes a set of platform-independent drivers to manage the

related AT commands.

│ │ ├───Modems

│ │ │ ├───BG96_STMOD+

│ │ │ │ └───AT_modem_bg96

│ │ │ └───UG96_STMOD+

│ │ │ └───AT_modem_ug96

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Folder structure

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STWIN The STWIN folder includes a set of medium level drivers for each hardware

subsystem running on this board (e.g., audio, environmental, motion, etc.).

│ │ ├───Modems

│ │ │ ├───BG96_STMOD+

│ │ │ │ └───AT_modem_bg96

│ │ │ └───UG96_STMOD+

│ │ │ └───AT_modem_ug96

CMSIS Vendor-independent hardware abstraction layer for ARM Cortex-M series, including

DSP Libraries used for all projects.

STM32L4xx_HAL_Driver

Microcontroller HAL libraries.

Middlewares This folder contains libraries oriented to provide, at high application level, specific APIs:

├───Middlewares

│ ├───ST

│ │ ├───STM32_Cellular

│ │ ├───STM32_Connect_Library

│ │ ├───STM32_MotionSP_Library

│ └───Third_Party

│ ├───AWS

│ ├───FreeRTOS

│ ├───jsmn

│ ├───mbedTLS

│ └───parson

STM32_Cellular Provides a Cellular Framework that is the software stack that allow to drive cellular

modem from STM32 MCU.

STM32_Connect_Library Provides API to access network services on STM32 devices.

STM32_MotionSP_Librar

Provides algorithms to analyze vibration in both time domain and frequency domain

using data coming from accelerometer.

AWS Provides the AWS IoT device SDK for embedded C that is a collection of C source files

which can be used in embedded applications to securely connect to the AWS IoT

platform.

FreeRTOS Provides a real-time operating system kernel for embedded devices. It is distributed

under the MIT License.

jsmn Provides a minimalistic JSON parser in C.

mbedTLS Provides cryptographic and SSL/TLS capabilities.

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Folder structure

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parson Provides a lightweight json library written in C.

Projects This folder contains the user level files of the application software:

├───Projects

│ ├───Demonstrations

│ │ └───C2C

│ │ └───AWS

│ │ ├───Binary

│ │ │ ├───STSW-STWINCELL_BG96_Vx.y.z.bin

│ │ │ └───STSW-STWINCELL_UG96_Vx.y.z.bin

│ │ ├───EWARM

│ │ ├───Inc

│ │ ├───MDK-ARM

│ │ ├───Src

│ │ └───STM32CubeIDE

│ ├───Utilities

│ │ ├───CLD_utils

│ │ ├───Misc_Utils

│ │ └───Time

Binary The Binary folder contains the firmware images, referred to the modem to be used,

ready to download into the MCU flash memory.

Inc and Src Inc and Src folders contain the application files.

EWARM IDE folder for IAR Embedded Workbench development environment

MDK-ARM IDE folder for Keil MDK-ARM development environment

STM32CubeIDE IDE folder for STM32CubeIDE development environment

Misc_Utils Misc_Utils contains application utilities.

Utilities This folder contains the useful tool for running the demo (e.g. tera term).

2.3 Application behavior

The firmware process management is controlled by an RTOS. The application is managed by tasks, semaphores,

queues and messages.

Before the osKerneStart() OS scheduler is started, the only task created is MainThread(…), which initializes

the platform, followed by the network, security, and the sensors along with their corresponding tasks.

Just before MainThread(…) terminates, it creates the cloud_run(…) application task, which starts the

connection handshake with AWS cloud and initiates all the structures associated with data transmission. Once the

handshake is performed, the cloud connection is managed as an infinite loop. If an error occurs, the loop is

bypassed and the Error_Handler() function runs.

Regarding the streaming times set on the dashboard, the environmental, inertial and acoustic data is prepared by

the publish_scheduler_callback(…) function that is called every 1000 ms. In the scheduler function, a

queue identifying the current feature is set. This queue is retrieved by the OS for the application task (i.e.,

cloud_run), so the data can be published on the cloud dashboard according to the dashboard streaming time.

The different types of data from the SensorTile Wireless Industrial Node are managed by the following functions:

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Application behavior

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•AUDIO_OS_Init(): for ultrasound analysis data, managed using threads, semaphores and messages

created in the function. DMA and interrupts are also used.

•ine_init(): for inertial analysis data, managed using a thread and a semaphore created inside the

function. External interrupt lines are also used.

• The environmental data is called on demand by an ad hoc task and not at regular intervals.

The tasks for acoustic and inertial analysis are run sequentially.

The required features can be selected in the aws_iot_config.h file. The user can choose any or all of the

following features by toggling the value of the following keywords:

• USE_ENV_FEAT

• USE_INE_TDM_FEAT

• USE_INE_FDM_FEAT

• USE_ACO_FEAT

RELATED LINKS

5 How to activate the ST Predictive Maintenance Dashboard on page 19

6 Demonstration application on page 24

2.4 IDE configuration selection

Each project comes with a separate configuration for each modem to be used.

Figure 4. IAR configuration selection

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IDE configuration selection

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Figure 5. Keil configuration selection

Figure 6. STM32CubeIDE configuration selection

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IDE configuration selection

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3Hardware setup

3.1 Set up and power supply

Step 1. Connect the battery to the STEVAL-STWINKT1.

Figure 7. STEVAL-STWINKT1 battery connection

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Hardware setup

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