The edge devices connected to the Cloud that constitute the Internet of Things (IoT) require support for building blocks, standards and frameworks like those provided by the Eclipse Foundation projects: Californium, Paho, Leshan, Kura, Mihini, etc. Because of the large deployment of Java technology in the Cloud, on the PC, mobile and server sides, most projects above are implemented in Java technology. Deploying these technologies on embedded devices requires a scalable IoT software platform that can support the hardware foundations of the IoT: microcontrollers (MCU). MCU delivered by companies like STMicroelectronics, NXP+Freescale, Renesas, Atmel, Microchip, etc. are small low-cost low-power 32-bit processors designed for running software in resource-constraint environments: low memory (typically KB), flash (typically MB) and frequency (typically MHz). The Edje project defines a standard high-level Java API called Hardware Abstraction Layer (HAL) for accessing hardware features delivered by microcontrollers such as GPIO, DAC, ADC, PWM, etc. that can directly connect to native libraries, drivers and board support packages provided by silicon vendors with their evaluation kits. This talk aims at presenting the packages and API that constitute the core of Edje, defining the minimal foundation that iot.eclipse.org projects can rely on, and still compatible with economical constraints of the IoT: footprint.

1. Eclipse IoT Day Grenoble 2016© IS2T S.A. 2016. All rights reserved.
EDJE PROJECT
The Software Foundation for IoT Devices
https://projects.eclipse.org/projects/iot.edje

2. Eclipse IoT Day Grenoble 2016
PRESENTER
Jérôme Leroux
Development and Innovation Manager at MicroEJ®
Edje Project Leader
10 years expertise in Java Embedded Systems
jerome.leroux@microej.com
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Other trademarks are proprietary of their respective owners.

3. Eclipse IoT Day Grenoble 2016
EDJE AND IOT
INTRODUCTION

4. Eclipse IoT Day Grenoble 2016
EDJE PROJECT
The Hardware Abstraction Java API for the IoT embedded systems
• Peripheral management
• Controller Communication Interfaces (Serial connection, CAN, SPI, I²C)
• Digital and Analog I/O (GPIO, ADC, DAC)
Scope
• Target resource-constrained micro-controller
• Provide ready-to-use software packages for target hardware
• Define a modular and easy to port framework
Project Status
• Eclipse IoT project
• Incubation

5. Eclipse IoT Day Grenoble 2016
IOT TOPOLOGY
IOT DEVICES GATEWAY SERVER
8/16/32-bit MCU Mono-Core
Frequency: < 200 MHz
Flash: < 1 MB
RAM: < 512 KB
32/64-bit MPU Multi-Core
Frequency: in GHz
Flash: in GB
RAM: in GB
MCU
MPU

6. Eclipse IoT Day Grenoble 2016
IOT HARDWARE
STM32F4 Discovery Raspberry PI 2
• Processor: 32-bits quad-core
Cortex-A7 (BCM2836)
• Frequency: 900 MHz
• RAM: 1 GB
• Flash: SD Card
• Processor: 32-bits Cortex-M4
(STM32F407VGT6)
• Frequency: 168 MHz
• RAM: 192 KB
• Flash: 1 MB

7. Eclipse IoT Day Grenoble 2016
EDJE APPLICATION FIELD
Sensors/Actuators
Local Network
Internet
A library at the edge of the IoT for
sensor hubs and devices

8. Eclipse IoT Day Grenoble 2016
EDJE REQUIREMENTS

9. Eclipse IoT Day Grenoble 2016
List of Java API
• The minimum execution environment provided by an Edje compatible
device
• Intersection between Java SE, Java SE Embedded, MicroEJ and Android
• Includes java.lang, java.util, java.io, …
EDJE DEVICE CONFIGURATION
J2SE
J2SE
Embedded
MicroEJ Android
Edje

10. Eclipse IoT Day Grenoble 2016
List of Java API
• The minimum execution environment provided by an Edje compatible
device
• Intersection between Java SE, Java SE Embedded, MicroEJ and Android
• Includes java.lang, java.util, java.io, …
EDJE DEVICE CONFIGURATION
Edje Device Configuration
Edje API
Edje Application
Library
Execution
Environment

11. Eclipse IoT Day Grenoble 2016
HARDWARE REQUIREMENTS
Minimal targeted Hardware
• Processor: 32-bits (e.g. Cortex-M0)
• Frequency: 16 MHz
• RAM: 32 KB
• Flash: 128 KB

12. Eclipse IoT Day Grenoble 2016
EDJE API

13. Eclipse IoT Day Grenoble 2016
EDJE API
Edje comes with the following services
Controller
Communication
Interfaces
Serial Port
CAN
Digital and
Analog I/O
GPIO
Peripheral
Management
LCD
USB Devices
Analog Input

14. Eclipse IoT Day Grenoble 2016
EDJE API
Peripheral Management
• List the peripherals of a platform
o MCU peripherals (UART, timer, USB controller, …)
o Board peripherals (screen, button, LED, sensors, …)
o External peripherals (USB devices, bluetooth devices, …)
• Peripheral plug/unplug notification system

15. Eclipse IoT Day Grenoble 2016
EDJE API
Controller Communication Interfaces
• Some peripherals can establish a connection to external devices
o Serial Connection (UART)
o Serial Peripheral Interface (SPI)
o Inter-Integrated Circuit (I²C)
o Controller Area Network (CAN)
• The peripheral implements Connectable interface
• Connection is described by a String
• Example with serial ports:
List<SerialPort> serialPorts = PeripheralManager.list(SerialPort.class);
for(SerialPort serialPort : serialPorts){
Connection connection = serialPort.openConnection("baudrate=115200;bitsperchar=8");
…
connection.close();
}

16. Eclipse IoT Day Grenoble 2016
EDJE API
Digital and Analog I/O
• Manage controller pins
• API inspired from Arduino C API
• General Purpose Input/Output (GPIO)
o LED, Buzzer, Button
• Analog to Digital Converter (ADC)
o Potentiometer, Temperature Sensor, Light Sensor
• Digital to Analog Converter (DAC)
o Speaker, Light Dimmer
• Pulse Width Modulation (PWM)
o Motor

17. Eclipse IoT Day Grenoble 2016
EDJE API
Digital and Analog I/O
• A pin is identified by the port and an ID
• Port name can be
o MCU specific
PortAPortB

18. Eclipse IoT Day Grenoble 2016
EDJE API
Digital and Analog I/O
• A pin is identified by the port and an ID
• Port name can be
o Board specific
J1
J2
J3
J4

19. Eclipse IoT Day Grenoble 2016
EDJE API
Digital and Analog I/O
• A pin is identified by the port and an ID
• Port name can be
o Standard
Digital Arduino
Analog Arduino

20. Eclipse IoT Day Grenoble 2016
REFERENCE
IMPLEMENTATIONS

21. Eclipse IoT Day Grenoble 2016
REFERENCE IMPLEMENTATIONS
Features
• Peripheral Management
• UART, USB CDC, GPIO, DAC, ADC
Hardware
• Raspberry-Pi 2
• Quad-Cortex-A7 @ 900 MHz
• RAM: 1 GB RAM
Platform
• Kura
• OpenJDK
• Linux

22. Eclipse IoT Day Grenoble 2016
REFERENCE IMPLEMENTATIONS
Features
• Peripheral Management
• UART, USB CDC, GPIO, DAC, ADC
Hardware
• STM32F746G-DISCO
• Cortex-M7 @ 200 MHz
• RAM: 8 MB
• Flash: 16 MB
Platform
• MicroEJ OS
• FreeRTOS
• STM32Cube

23. Eclipse IoT Day Grenoble 2016
REFERENCE IMPLEMENTATIONS
Features
• Peripheral Management
• UART, USB CDC, GPIO, DAC, ADC
PC Simulation
• Java® SE
• Hardware In the Loop Simulation (HIL)
Execution
Flow
Ethernet
or Serial

24. Eclipse IoT Day Grenoble 2016
EDJE ROADMAP

25. Eclipse IoT Day Grenoble 2016
POTENTIAL ROADMAP
Features
• I²C, SPI
• Controller Area Network (CAN)
• Power Management
• Sensor
Reference Implementations
• MicroEJ Renesas Synergy Cortex-M4
• MicroEJ NXP Kinetis Cortex-M0+

26. Eclipse IoT Day Grenoble 2016
CALL TO ACTION

27. Eclipse IoT Day Grenoble 2016
DEMO
=
+ +
over MicroEJSTM32F746G-DISCO Arduino Multi-function
Shield