"[contents]
Physical display
Core chip
Sensor peripherals
Hardware system framework
Low power design
Software development environment
Pre installed demo demo
Project code analysis
Evaluation summary
For many years, silicon labs has focused on products with performance, energy saving, connectivity and simplicity, providing chips, software and solutions for a smarter and more interconnected world. They recently launched an Internet of things development board thunderboard efr32bg22, which is a small single-chip ideal Bluetooth Internet of things development platform with rich functions. It can be demonstrated as a product prototype, and can also be used as a development platform for testing, debugging and verification.
Let's watch the official video first
Physical display
The thunderboard efr32bg22 IOT board is installed in a color carton smaller than the credit card. The barcode label on the back of the carton identifies the product model, material number, serial number and date information.
There is only the product body and a quick start card in the packing box.
The thunderboard efr32bg22 IOT board is very compact, and the arrangement of components on the board is also very compact.
Core chip
The core chip of thunderboard efr32bg22 IOT board adopts the single-chip Bluetooth wireless chip of silicon labs, and the model is efr32bg22c224f512im40, which is the top configuration in this series of chips.
This chip is based on ARM cortex ®- M33 core, the maximum operating frequency can reach 76.8mhz;
512KB flash memory and 32KB running memory;
Integrated PA, transmitting power up to 6 DBM in 2.4GHz band;
It supports low-power Bluetooth 5.2, direction finding function of Bluetooth 5.2 and Bluetooth mesh.
This chip is a new generation v8m architecture of arm, which has been enhanced in terms of security. The security features are as follows:
Support secure boot with root of trust and secure loader (RTSL)
Hardware Cryptographic Acceleration for AES128/256, SHA-1, SHA-2 (up to 256-bit), ECC (up to 256-bit), ECDSA,and ECDH
True Random Number Generator (TRNG) compliant with NIST SP800-90 and AIS-31
ARM TrustZone
Secure Debug with lock/unlock
This chip integrates an energy-efficient RF module with extremely low power consumption and sleep current. When Bluetooth sends and receives data, the working current is 3.8/8.4ma respectively. In em0 mode, the working current is 28 μ A / MHz, in em2 deep sleep mode, the current consumption is 1.40 μ A/ 1.75 μ A. In em4 mode, only 0.17 is consumed μ A current.
Sensor peripherals
Thunderboard efr32bg22 IOT board contains rich peripherals:
Relative humidity and temperature sensor
Ultraviolet and ambient light sensors
Magnetic, Hall effect sensor
6-axis inertial sensor
The thunderboard efr32bg22 IOT board is small in size, and the mini is only 30.4mm x 45.4mm. It is a complete hardware development platform. As a development board, it has many functions, such as:
With LED indicator and key, it can interact with users;
The development board leads out 20 pin 2.54 mm breakout pads, and users can expand the functions themselves;
On board segger j-link on-board debugger can be downloaded and debugged without additional debugger;
With virtual serial port function;
Develop onboard 2.4 GHz ceramic chip antenna; With power control device to control the power consumption of development board; 8Mbit OTA flash memory is preset on the board, which can be used for online upgrade or data login;
Hardware system framework
The system framework of the development board is shown in the figure below. The whole development board is based on efr32bf22 Bluetooth single chip, adds necessary 2.4GHz antenna and flash memory, adds development and debugging module debugger and user IO, and adds various sensors to form the thunderboard efr32bg22 IOT board system.
Low power design
The power input terminal can be selected from three, which is convenient for users.
There are 4 sensors and 1 flash on board, a total of 5 devices, using only 2 interfaces of the core chip, I2C interface and SPI interface.
The development board has designed a set of power devices for each sensor, as shown in the white box below, to finely manage the power consumption of peripheral devices and achieve the ultimate goal of power saving and low power consumption in hardware design.
Software development environment
The software development environment of silicon labs products is simplicity studio. One software can handle all development environments. Now it has been updated to simplicity studio V5, but don't worry. Both versions can be used. The official website clearly indicates that both versions of V4 and V5 can be installed on the same computer at the same time, so as to dispel users' concerns.
The installation of simplicity studio V4 went smoothly. There was a problem when updating SDK components in simplicity studio V5, which needs to be handled manually. Everything else is normal.
The author also strongly recommends using V5 for three reasons:
V4 is currently in maintenance status, V5 is active, and V5 is better supported
The gecko SDK version of V4 is 2.7, and the gecko SDK version of V5 is 3.0 or newer
V4 does not support the security library technology. V5 supports the security library technology and can be perfectly combined with the silicon labs Bluetooth wireless chip efr32bg22. The cooperation of software and hardware greatly improves the security of Internet of things applications.
Simplicity studio V5 development software interface is slightly different from V4 in use mode and interface. If you are familiar with V4, you can easily and seamlessly switch to V5.
Simplicity studio V5 is easy to install and manage various SDK components, consult chip information help documents, etc
Simplicity studio V5 is as big and complete as ever:
Code editing interface:
Pre installed demo demo
The thunderboard efr32bg22 IOT board can push the data to the mobile phone for display in real time with the mobile application on the mobile phone.
First install the thunderboard app of silicon labs on the mobile phone and then open it. Power up the thunderboard efr32bg22 Internet of things board. The mobile app can search the thunderboard efr32bg22 device. Click the automatic link of thunderboard efr32bg22 #51069 device to open the dashboard interface, which displays three modules: motion, environment and Io.
The motion module obtains the data of 6-axis inertial sensor, 3-axis azimuth and 3-axis gravity acceleration of thunderboard efr32bg22 physical grid plate in real time. While rotating the development board, the 3D model on the mobile phone rotates synchronously with the real object in real time.
The environment module obtains the data of the relative humidity and temperature sensor, ultraviolet and ambient light sensor and magnetic Hall effect sensor of the development board in real time.
The IO module can control the LED of the development board through the switch of the mobile phone, and update the status of the switch switch on the mobile phone through the button button of the development board, so as to realize the interaction between the user and the system;
Project code analysis
There are several official projects in simplicity studio V5. The author will analyze the project Bluetooth - SOC thunderboard efr32bg22 pre installed in the factory of this development board:
Starting from the main function of the project code, the main function initializes the thunderboard efr32bg22 system sl_ system_ Init, and then initialize the app_ Init, the last while (1) loop, which continuously handles system events SL_ system_ process_ Action, application event app_ process_ Action, and then run SL_ power_ manager_ Sleep enables the system to sleep and save power. The code is as follows:
Several functions in the main function are analyzed one by one:
one System initialization sl_ system_ In the init function, the first two are platform and driver initialization. MCU development is very common. Skip and look at service initialization sl_ service_ init() 。
Service initialization sl_ service_ Init contains:
one point one Sleep clock initialization sl_ sleeptimer_ Init() is mainly used to set the frequency and initialize. The function is that after the system hibernates, the clock still works to regularly wake up the system and deal with events.
one point two IO initialization sl_ iostream_ init_ Instances(), initialize UART. You can output information through the virtual COM port.
one point three sl_ mbedtls_ Init is empty, nothing.
one point four MPU initialization sl_ mpu_ disable_ execute_ from_ Ram, do some initialization work related to energy saving.
two System initialization sl_ system_ SL in init_ stack_ Init () is the initialization of Bluetooth protocol stack. Bluetooth initialization is all here.
three System initialization sl_ system_ SL in init_ internal_ app_ Init() is empty.
four app_ init(); It's empty.
five sl_ system_ process_ Action () is used to handle platform, service, stack and interface_ App events and Bluetooth events are also handled here.
six app_ process_ action(); Post processing after reading UART command is equivalent to interactive service of shell.
seven sl_ power_ manager_ Sleep() finds the most energy-saving sleep mode, wakes up when there is an event, starts processing, and comes here to sleep and save power after processing.
More detailed code can be read and analyzed by yourself.
For the whole project, first initialize the platform, initialize peripherals, initialize low-power power management, then initialize the Bluetooth protocol stack, set UART interaction, and finally enter the dead cycle to continuously deal with UART interaction, Bluetooth protocol stack events, sleep and wake up.
The overall project code logic is relatively simple, modular code, clear naming, very friendly to developers, reference learning is of great significance, and is also very important to development.
Evaluation summary
Thunderboard efr32bg22 IOT board is a single-chip low-power Bluetooth development platform, a multi-functional demo display board, and a complete hardware development system platform. The board is small in size but full of functions. It has all the functions of a development board and can be used out of the box.
Thunderboard efr32bg22 IOT board software development environment provides family bucket services, SDK download management, graphical configuration, code editing, compilation, download and debugging, etc., with up to 21 official projects. The code is beautiful, which can easily help developers clarify the project structure and code operation process.
The software and hardware development environment of thunderboard efr32bg22 IOT board is integrated with each other, and the code and data documents are relatively open, which can help the company speed up product development and reduce the work of engineers, which is a great benefit to the company and employees. Bluetooth chip level hardware security features are combined with the software security library developed by simplicity studio V5 to raise the security of Internet of things applications to a new level.
The low power consumption of thunderboard efr32bg22 IOT board is the ultimate. There is a power management module on the hardware and a low-power sleep mode on the software. It can be seen that silicon labs, which has focused on energy conservation for many years, does have its own characteristics.
There are more than 15 large and small chips on the thunderboard efr32bg22 Internet of things board, which is a monster of stacking materials. In terms of development environment software, it is also extremely stacking materials. The appearance is ordinary, and the small and insignificant thunderboard efr32bg22 board is naturally low-key and luxurious, Mini + extreme low power consumption + multifunction + software and hardware security + integrated development environment + open official routines + rich manual documents. It's not too much to call thunderboard efr32bg22 the benchmark of Internet of things development board“
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