Baidu_UM_Neutral Baidu User Manual V2

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December 2017 1/27

User

manual

Getting started with I-CUBE-BAIDU

IoT

cloud

software

expansion for

STM32Cube

Introduction

This user manual describes the content of the STM32Cube software expansion

package for the BAIDU

IoT (Internet of things) cloud platform.

The BAIDU

IoT cloud software expansion package I-CUBE-BAIDU for STM32Cube

provides application examples that connect STMicroelectronics boards to the BAIDU

IoT platform. It uses the BAIDU

iot-edge-sdk library which is compiled and running

on STM32 devices.

I-CUBE-BAIDU runs on the B-L475E-IOT01 and 32L496GDISCOVERY boards.

Implementation examples are included for device-to-cloud telemetry reporting, and

cloud-to- device messages for notifications to the connected devices.

I-CUBE-BAIDU offers the following features:

•

Ready to run firmware example using Wi-Fi

and Cellular connectivity to support

quick evaluation and development of BAIDU

IoT node applications

•

Board configuration interface

•

Wi-Fi

or cellular connection

•

Connection to the BAIDU

IoT cloud platform

•

The B-L475E-IOT01 board measures and reports the following values:

– Humidity

– Temperature

– 3D magnetic data

– 3D acceleration

– 3D gyroscope data

– Atmospheric pressure

– Proximity

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Contents

General information ............................................................................. 5

BAIDU ® IoT cloud platform ................................................................ 6

Package description ............................................................................ 7

3.1

General description ........................................................................................... 7

3.2

Architecture ....................................................................................................... 9

3.3

Folder

structure

.............................................................................................. 10

3.4

B-L475E-IOT01 board

sensors

........................................................................ 11

3.5

Wi-Fi® components ........................................................................................ 13

3.6

Reset push-button (black) ............................................................................... 13

3.7

User push-button (blue) .................................................................................. 13

3.8

User LED ......................................................................................................... 14

3.9

mbedTLS configuration ................................................................................... 14

Hardware and software environment

setup

..................................... 15

Interacting with the boards................................................................ 17

Application examples ........................................................................ 19

6.1

Application description .................................................................................... 19

6.2

Application setup ............................................................................................. 19

6.2.1

Baidu device creation .................................................................................................. 19

6.3

Application build and flash .............................................................................. 21

6.3.1

WiFi Application first launch......................................................................................... 21

6.3.2

WiFi Application runtime .............................................................................................. 22

6.3.3

Cellular Application first launch ................................................................................... 23

6.3.4

Cellular Application runtime ......................................................................................... 24

Frequently asked questions .............................................................. 26

Revision history ................................................................................. 27

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List of tables

Table 1. List of acronyms ........................................................................................ 5

Table 2. Units for the values reported by the sensors of the B-L475E-IOT01 board

............................................................................................................................... 13

Table 3. Document revision history....................................................................... 27

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List of figures

Figure 1. BAIDU IoT ecosystem .............................................................................. 6

Figure 2. B-L475E-IOT01A board ........................................................................... 7

Figure 3 - 32L496GDISCOVERY board .................................................................. 7

Figure 4. I-CUBE-BAIDU software architecture .................................................... 10

Figure 5. Project File structure .............................................................................. 11

Figure 6. Hardware and software setup environment ........................................... 15

Figure 7. Purchase BAIDU® SIM card .................................................................. 16

Figure 8. BAIDU® IoT Cloud account creation ..................................................... 16

Figure 9. Terminal setup ........................................................................................ 17

Figure 10. Serial port setup ................................................................................... 18

Figure 11. IoT hub instance ................................................................................... 19

Figure 12. Device instance .................................................................................... 19

Figure 13. Node principal creation ........................................................................ 20

Figure 14. Node policy and topic setting ............................................................... 20

Figure 15. Topic permission setting ...................................................................... 20

Figure 16. Credential provisioning......................................................................... 21

Figure 17. WiFi credential...................................................................................... 22

Figure 18. Data publishing .................................................................................... 22

Figure 19. WEB Console ....................................................................................... 23

Figure 20. EMnify APN ......................................................................................... 23

Figure 21. BAIDU APN .......................................................................................... 24

Figure 22. Cellular application runtime .................................................................. 25

Figure 23. Web Console ........................................................................................ 25

Figure 24Pop-up when the IAR™ IDE version is not compatible with the one used

for I-CUBE-BAIDU ................................................................................................. 26

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1 General information

The I-CUBE-BAIDU package for the BAIDU

IoT cloud platform runs on STM32 32-

bit microcontrollers based on the Arm® Cortex®-M processor.

Table 1 presents the definition of acronyms that are relevant for a better understanding

of this document.

Table 1. List of acronyms

erm

Definition

API Application programming interface

BSP Board support package

CA Certification authority

DHCP Dynamic host configuration protocol

DNS Domain name server

HAL Hardware abstraction layer

IDE Integrated development environment

IoT Internet of things

IP Internet protocol

LED Light-emitting diode

RTC Real-time clock

UART Universal asynchronous receiver/transmitter

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2 BAIDU

IoT cloud platform

This chapter introduces the BAIDU

IoT cloud platform.

The I-CUBE-BAIDU package implements the BAIDU

iot-edge-sdk library which

allows the board to securely connect to the BAIDU

IoT cloud platform.

A user can connect to the cloud with a smartphone or personal computer and have

access to the information provided by the board at any time and from any location.

Figure 1 presents the BAIDU

IoT cloud ecosystem targeted by the I-CUBE-BAIDU

package.

Figure 1. BAIDU IoT ecosystem

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3 Package description

This chapter details the I-CUBE-BAIDU package content and the way to use it.

3.1 General description

The I-CUBE-BAIDU package provides a BAIDU

stack middleware for STM32

microcontrollers.

It is built to run on the B-L475E-IOT01 and 32F496GDISCOVERY boards and

connects to the Internet through the on-board network interface:

•

B-L475E-IOT01 supports Wi-Fi

connectivity with an on-board Inventek

WiFi

module. This board is equipped with a set of sensors able to report humidity,

temperature, 3D-axis magnetic data, 3D accelerations, 3D gyroscope data,

atmospheric pressure, proximity and gesture detection (I-CUBE-BAIDU does not use

the gesture detection capability).

Figure 2. B-L475E-IOT01A board

•

32L496GDISCOVERY provides a STmod+ interface that is connected to an external

Quectel

UG96 cellular modem.

Figure 3 - 32L496GDISCOVERY board

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The package is split into the following software components:

•

Client libraries and samples for connecting to BAIDU

IoT cloud platform

•

mbedTLS

•

Wi-Fi

and cellular drivers

•

Sensor drivers for the B-L475E-IOT01 board

•

STM32L4 Series HAL

•

BAIDU

application examples

The software is provided as a zip archive containing source code. The following

integrated development environments are supported:

•

IAR Embedded Workbench

for Arm

(EWARM)

•

Keil

Microcontroller Development Kit (MDK-ARM)

•

System Workbench for STM32

Note: refer to the release note available in the package root folder for information

about the IDE versions supported.

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3.2 Architecture

This section describes the software components of the I-CUBE-BAIDU package.

The I

-CUBE-BAIDU

software is an expansion for the STM32Cube. Its main features and

characteristics are:

•

Fully compliant with STM32Cube architecture

•

Expands STM32Cube in order to enable the development of applications accessing

and using the BAIDU

IoT cloud platform

•

Based on the STM32CubeHAL, which is the hardware abstraction layer for STM32

microcontrollers

The software components used by the application software to access and use the

BAIDU

IoT cloud platform are the following:

1. STM32Cube HAL

The HAL driver layer provides a generic multi-instance simple set of APIs (application

programming interfaces) to interact with the upper layers (application, libraries and

stacks).

It is composed of generic and extension APIs. It is directly built around a generic

architecture and allows the layers that are built upon, such as the middleware layer, to

implement their functionalities without dependencies on the specific hardware

configuration for a given microcontroller unit (MCU).

This structure improves the library code reusability and guarantees an easy portability

onto other devices.

2. Board support package (BSP)

The software package needs to support the peripherals on the STM32 boards apart

from the MCU. This software is included in the board support package (BSP). This is a

limited set of APIs which provides a programming interface for certain board specific

peripherals such as the LED and the user button.

3. BAIDU

iot-edge-sdk

4. mbedTLS

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Figure 4 outlines I-CUBE-BAIDU software architecture.

Figure 4. I-CUBE-BAIDU software architecture

3.3 Folder

structure

Figure 5 presents the folder structure of the

I-CUBE-BAIDU package.

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Figure 5. Project File structure

3.4 B-L475E-IOT01 board

sensors

The sensors that are present on the board and used by the sample application are:

•

Capacitive digital sensor for relative humidity and temperature (HTS221)

•

High-performance 3-axis magnetometer (LIS3MDL)

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•

3D accelerometer and 3D gyroscope (LSM6DSL)

•

260-1260 hPa absolute digital output barometer (LPS22HB)

•

Proximity sensor (VL53L0X)

Example of a published sensor message:

{"d":

{

"temperature": 31.39856,

"humidity": 29.069721,

"pressure": 997.830017,

"proximity": 8190,

"accX": -13,

"accY": -14,

"accZ": 1024,

"gyrX": 1750,

"gyrY": -4970,

"gyrZ": 1470,

"magX": 170,

"magY": -180,

"magZ": 605,

}

Table 2 presents the units for the values reported by the sensors of the B-L475E-

IOT01 board.

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Table 2. Units for the values reported by the sensors of the B-L475E-IOT01

board

Data

Unit

Temperature degree Celsius (°C)

Humidity relative humidity (%)

Pressure hectopascal (hPa)

Proximity millimeter (mm)

Acceleration milli g-force (mgforce)

Angular

velocity

millidegree per second (mdps)

Magnetic

induction

milligauss

(mG)

3.5 Wi-Fi® components

The Wi-Fi

software is split over

Drivers/BSP/Components

for the module specific

software and over Projects/<board>/WiFi for I/O operations and for the Wi-Fi

module

abstraction.

3.6 Reset push-button (black)

The reset push-button (black) is used to reset the board at any time. This action makes

the board reboot.

3.7 User push-button (blue)

The user push-button (blue) is used in the following cases:

•

To configure the Wi-Fi

and BAIDU

security credentials. This can be done from the

time the board starts up and up to five seconds after that.

The application configures and manages the user button via the board support

package

(BSP) functions.

The BSP functions are in the Drivers\BSP\<board name> directory.

When using the BSP button functions with the BUTTON_USER value, the application

does not take into account the way this button is connected from a hardware

standpoint for a given platform. The mapping is handled by the BSP.

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3.8 User LED

The configuration of the user LED that is used by the applications is done via the

board support package (BSP) functions.

The BSP functions are under the Drivers\BSP\<board name> directory.

Using the BSP button functions with the LED_GREEN value, the application does not

take into account the way the LED is mapped for a given platform. The mapping is

handled by the BSP.

3.9 mbedTLS configuration

The mbedTLS middleware is fully configurable by means of a #include

configuration file.

The name of the configuration file can be overridden by using the following statement:

MBEDTLS_CONFIG_FILE

#define.

The I-CUBE-BAIDU package uses

az_mbedtls_config.h

file for project configuration.

This is implemented by having the following # directives at the beginning of the

mbedTLS.c and mbedTLS.h files:

#if !defined(MBEDTLS_CONFIG_FILE)

#include "mbedtls/config.h"

#else

#include MBEDTLS_CONFIG_FILE

#endif

The configuration file specifies the ciphers to integrate.

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4 Hardware and software environment

setup

To set up the hardware and software environment, one of the two supported boards

must be plugged into a personal computer via a USB cable. This connection with the

PC allows the user to:

•

Flash the board

•

Store the Wi-Fi

or the cellular credentials

•

Interact with the board via a UART console

•

Debug

The B-L475E-IOT01 board must be connected to a Wi-Fi

access point while the

32L496GDISCOVERY board + Quectel UC96 cellular modem must be connected to

cellular network as illustrated in Figure 6.

Figure 6. Hardware and software setup environment

The prerequisites for running the WiFi example are:

•

A MCU board: B-L475E-IOT01 (MB1297 rev D), with FW "Inventek eS-WiFi

ISM43362-M3G-L44-SPI C3.5.2.3.BETA9" (Note: the FW is already included in the

package and the version is displayed on the board console at boot time).

•

A Wi-Fi

access point, with a transparent Internet connectivity meaning that neither

a proxy, nor a firewall are blocking the outgoing traffic. It has to run a DHCP server

delivering the IP and DNS configuration to the board.

The prerequisite for running the Cellular example are:

•

A MCU board: STM32L496G-Discovery board equipped with a Quectel UG96

daughterboard connected on its IO expander: Modem package upside, SIM card slot

downside.

•

A cellular access point.

•

An active cellular SIM card must be fit in the slot.

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To purchase BAIDU® SIM card, you can follow the steps described in this link

https://cloud.baidu.com/doc/Pricing/IOT/14.5C.E5.8D.87.E7.BA.A7-1.html

Figure 7. Purchase BAIDU® SIM card

In both cases you will also need:

•

A computer for running the device management application, with transparent Internet

connectivity meaning that neither a proxy, nor a firewall blocking the outgoing traffic.

This can for instance be the development PC, a virtual private server or a single- board

computer. It can be connected to the same router as the MCU board.

•

A development PC for building the application, programming through ST-Link, and

running the virtual console

•

A Baidu IoT cloud account to create an IoT Hub.

https://login.bce.baidu.com/?lang=en.

Figure 8. BAIDU® IoT Cloud account creation

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5 Interacting with the boards

A serial terminal is required to:

•

Configure the WiFi AP or cellular APN credential on the node

•

Display locally the received BAIDU

IoT cloud-to-device messages

The example in this document is illustrated with the use of Tera Term. Any other similar

tool can be used instead.

When the board is used for the first time, it must be programmed with BAIDU

IoT

device credentials (endpoint / username / password). (Please refer to section 6.2.1 to

get the BAIDU

credentials).

•

Determine the STM32 ST-LINK Virtual COM port used on the PC for the Discovery

board.

•

Open a virtual terminal on the PC and connect it to the above virtual COM port.

A Tera Term initialization script is provided in the package utility directory (refer to

Figure 9); this script sets the correct parameters. To use it, open Tera Term, select

Setup and then Restore setup.

Note: The information provided below in this chapter can be used to configure the UART

terminal as an alternative to using the Tera Term initialization script.

Terminal setup is illustrated in Figure 9, which shows the terminal setup and the New-

line recommended parameters.

The virtual terminal New-line transmit configuration must be set to LineFeed (\n or LF)

in order to allow copy-paste from UNIX type text files. The Local echo option makes

copy- paste visible on the console.

Figure 9. Terminal setup

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The serial port must be configured with:

•

COM port number

•

115200 baud rate

•

8-bit data

•

Parity none

•

1 stop bit

•

No flow control

Serial port setup is illustrated in Figure 10.

Figure 10. Serial port setup

Once the UART terminal and the serial port are set up, press the board reset button

(black). Follow the indications on the UART terminal to upload Wi-Fi

AP or cellular

APN data. Those data remain in Flash and are reused the next time the board boots.

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6 Application examples

6.1 Application description

The Baidu Sample application illustrates the various ways for a device to interact

with a Baidu IoT hub, using the Baidu IoT edge SDK for C.

The application connects to a Baidu IoT hub thanks to the credentials provided

by the user on the code.

6.2 Application setup

In order to make the program work, it is necessary to follow these steps:

6.2.1 Baidu device creation

Create a Baidu IoT hub instance and a device under your instance.

Figure 11. IoT hub instance

Create a device under your instance.

Figure 12. Device instance

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Create a node principal to get password

Figure 13. Node principal creation

Create a node policy and topic

Figure 14. Node policy and topic setting

Set the Topic Permission

Figure 15. Topic permission setting

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6.3 Application build and flash

Open the project with one of the supported development tool chains, enter the Baidu

IoT hub instance address (ENDPOINT), device username and password into the

source file under iothub_mqtt_client_wifi_sample.c or

iothub_mqtt_client_c2c_sample.c.

Figure 16. Credential provisioning

Build the project with one of the supported development toolchain

Program the firmware on the STM32 board: you can copy (or drag and drop) the

generated bin file to the USB mass storage location created when you plug the

STM32 board to your PC.

Alternatively, you can program the STM32 board directly through one of the supported

development tool chains

6.3.1 WiFi Application first launch

The board must be connected to a PC through USB (ST-LINK USB port).

On the console of WiFi-enabled board (B-L475E-IOT01): Enter your WiFi SSID,

encryption mode and password

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Figure 17. WiFi credential

After the parameters are configured, it is possible to change them by

restarting the board and pushing the User button (blue button) just after boot.

6.3.2 WiFi Application runtime

Once the connection to BAIDU IoT Hub is established, the board will keep publishing

the on-board sensor data to the IoT Hub.

Figure 18. Data publishing

It is also possible to subscribe to the data published on the IoT Hub.

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From the Web Console, you can observe the data that have been published by the

node

Figure 19. WEB Console

6.3.3 Cellular Application first launch

The board must be connected to a PC through USB (ST-LINK USB port)

On the console from cellular enable board (STM32L496G-Discovery board equipped

with a Quectel UG96 modem), you will need to enter the C2C network configuration

(SIM operator access point code, username and password).

Example:

with Emnify SIM: access point: "EM", username: "", password: ""

Figure 20. EMnify APN

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with Baidu SIM: access point: "lnsyszhx01.schj.njm2mapn", username: "", password: ""

Figure 21. BAIDU APN

IMPORTANT: Baidu SIM Card is node-locked, i.e. the Baidu APN will lock the SIM

card to the node device (here ST STM32L496G-DISCO board) after the first usage.

Switching the Baidu SIM card to another node devices without permission from Baidu

will fail to retrieve APN and IP address during initialization stage

After the parameters are configured, it is possible to change them by restarting the

board and pushing the User button (blue button) just after boot.

6.3.4 Cellular Application runtime

Once the connection to BAIDU IoT Hub is established, the board will keep publishing

a “test message” text to the IoT Hub.

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Figure 22. Cellular application runtime

From the Web Console, you can observe the data that have been published by the

node

Figure 23. Web Console

26/27

7 Frequently asked questions

Q: Why do I get this pop-up (refer to Figure 24) when I open the project with IAR™?

Figure 24Pop-up when the IAR™ IDE version is not compatible with the one

used for I-CUBE-BAIDU

A: It is very likely that the IAR™ IDE version is older than the one used to develop the

package (refer to the release note available in the package root folder for the IDE

versions supported), hence the compatibility is not ensured. In this case, the IAR™

IDE version needs to be updated.

Q: How shall I modify my application to publish other messages?

A: Depending weither B-L475E-IOT01or 32L496GDISCOVERY boards are used, an

update of the function PrepareMqttPayload() or PrepareToggleMqttPayload()

respectively is needed in the file iothub_mqtt_client_wifi_sample.c or

iothub_mqtt_client_c2c_sample.c.

Q: My device does not connect to the Wi-Fi

access point. How shall I proceed?

A: Make sure that another device can connect to the Wi-Fi

access point. If it can,

enter the Wi-Fi

credentials by pressing the user button (blue) up to five seconds after

board reset.

Q: The proximity sensor always reports "8190" even if I place an obstacle close to it.

A: Make sure that the liner (which is a very thin film placed on the proximity sensor)

has been removed. Its color is orange and it is not very visible.

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8 Revision history

Table 3. Document revision history

Date

Changes

8-Dec-2017 1 Initial release.

Baidu_UM_Neutral Baidu User Manual V2

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