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1 Introduction

FriendlyThings is an Android SDK developed by FriendlyElec to access hardware. Users can use it to access various hardware resources Uart, SPI, I2C, GPIO etc on a FriendlyElec ARM board under Android. This SDK is based on Android-NDK. Users can use it to develop popular IoT applications without directly interacting with drivers.

2 Android Versions

The Android BSPs provided by FriendlyElec already have FriendlyThings SDK( and currently have the following versions:

2.1 RK3399

  • Android 7.1.2-rk3399

BSP source code download link:
Latest ROM download link:

  • Android 8.1-rk3399

BSP source code download link:
Latest ROM download link:

2.2 S5P6818

  • Android 5-s5p6818

BSP source code download link: TODO
Latest ROM download link: TODO

2.3 S5P4418

  • Android 4.4-s5p4418

BSP source code download link: TODO
Latest ROM download link: TODO

  • Android 5-s5p4418

BSP source code download link: TODO
Latest ROM download link: TODO

2.4 Tiny4412

  • Android 4.2-exynos4412

BSP source code download link: TODO
Latest ROM download link: TODO

  • Android 5-tiny4412

BSP source code download link: TODO
Latest ROM download link: TODO

2.5 Tiny210/Smart210/Mini210

  • Android 4.2-S5pv210

BSP source code download link: TODO
Latest ROM download link: TODO

2.6 Tiny6410/Mini6410

  • Android 2.3-s3c6410

BSP source code download link: TODO
Latest ROM download link: TODO

3 List of Applicable Boards

FriendlyThings SDK( works with the following boards:

3.1 RK3399

  • NanoPC-T4
  • NanoPi M4 (an external eMMC module is needed)
  • NanoPi NEO4 (an external eMMC module is needed)

3.2 S5P6818

  • NanoPC T3
  • NanoPi M3
  • NanoPi Fire3
  • Smart6818

3.3 S5P4418

  • Smart4418 SDK
  • NanoPC T2
  • NanoPi M2A
  • NanoPi Fire2A
  • NanoPi S2

3.4 Exynos4412

  • Tiny4412

3.5 S5PV210

  • Tiny210
  • Smart210
  • Mini210

3.6 S3C6410

  • Tiny6410
  • Mini6410

4 Quick Start

4.1 Step 1: Include in APP

Clone the following library locally:

git clone

Copy all the files under the libs directory to your working directory and create a "com/friendlyarm" directory in your Android project's src directory, copy the whole "java/FriendlyThings" to your newly created "com/friendlyarm" directory. The whole project directory will look like this(Note:AndroidStudio's project may be a little bit different):

├── AndroidManifest.xml
├── libs
│   ├── arm64-v8a
│   │   └──
│   └── armeabi
│       └──
├── src
│   └── com
│       └── friendlyarm
│           ├── FriendlyThings
│           │   ├──
│           │   ├──
│           │   ├──
│           │   ├──
│           │   ├──
│           │   ├──
│           │   └──

Import the following components and the major APIs are included in the file:

import com.friendlyarm.FriendlyThings.HardwareControler;
import com.friendlyarm.FriendlyThings.SPIEnum;
import com.friendlyarm.FriendlyThings.GPIOEnum;
import com.friendlyarm.FriendlyThings.FileCtlEnum;
import com.friendlyarm.FriendlyThings.BoardType;

4.2 Step 2: Give APP System Right

Your app needs the system right to access hardware resources;
Give your app the system right by making changes in the AndroidManifest.xml file and the file;
It is better to include your app in your Android source code and compile them together. If your app is not compiled together with your Android source code you have to go through tedious steps to compile your app and sign your app to give it the system right.

4.2.1 Modify AndroidManifest.xml

Add the following line in the manifest node in the AndroidManifest.xml file:


4.2.2 Modify

Create an file(the simplest way is to copy a sample file), modify the file by adding a line LOCAL_CERTIFICATE := platform :

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := $(call all-subdir-java-files)
LOCAL_CFLAGS := -lfriendlyarm-hardware
include $(BUILD_PACKAGE)

4.3 Final Step: Compile Your APP Together with Android Source Code

Go to Android source code's root directory and run "" to export environmental variables, enter your app's directory and run "mm" to compile:
For example: compile the GPIO_LED_Demo on RK3399:

cd rk3399-android-8.1
cd vendor/friendlyelec/apps/GPIO_LED_Demo

4.4 Sample project in Android Studio

5 APIs for Library

Refer to this WiKi:FriendlyThings APIs

6 Code Samples

7 Compile & Deploy Andorid Code (SerialPortDemo)

7.1 Step 1. Import source code in eclipse (SerialPortDemo)

Start eclipse, click on "Import" on its main window's File menu and then select "Existing Android Code Into Workspace" to import your source code
We name this project as "SerialPortDemo"

  • AndroidHW01.png
  • AndroidHW02.png

7.2 Step 2. Edit source code

The names of serial devices this DEMO accesses are listed in this file: src/com/friendlyarm/SerialPortDemo/
Make changes according to your devices' names:

7.2.1 Serial Device Names under Multiple Platforms

  • Allwinner H3/H5 Based Boards (NanoPi M1/NanoPi M1 Plus etc)

UART1-> /dev/ttyS1
UART2 -> /dev/ttyS2
UART3 -> /dev/ttyS3 (Only applies to NanoPi M1, NanoPi K1 and NanoPi K1 Plus)

  • S5P4418 Based Boards (NanoPi Fire2A/NanoPi M2A/NanoPi S2/NanoPC-T2 etc)

UART1 -> /dev/ttyAMA1 [Note 1]
UART2 -> /dev/ttyAMA2 [Note 1]
UART3 -> /dev/ttyAMA3
UART4 -> /dev/ttyAMA4

  • S5P6818 Based Boards (NanoPi M3/NanoPC-T3 etc)

UART1 -> /dev/ttySAC1 [Note 1]
UART2 -> /dev/ttySAC2 [Note 1]
UART3 -> /dev/ttySAC3
UART4 -> /dev/ttySAC4

Note 1: only applies to specific boards, you need to check if a board has that serial device populated.

7.3 Step 3. Compile DEMO's source code and export apk file

On "Package Explorer" check your project's name:
On eclipse's main menu select "File" and then "Export...":
Select "Export Android Application":
Select "SerialPortDemo":
Eclipse requires you to create a new keystore or select an existing keysotre in this step. In this case we selected "Create new keystore", set a path to store the key and created its password and then clicked on "next":
Refer to the following screenshot to fill more information and click on "next":
Select a path to store your APK file. In this case we set it to a "signapk-files" directory:
Click on "Finish" to export an APK file.

7.4 Step 4. Give APK New Signature

For a program to access a hardware device that program needs to have "system" right therefore you need to give your APK a new signature.
Enter the signapk-files directory and give your APK a new signature:

cd signapk-files/
java -jar ./signapk.jar platform.x509.pem platform.pk8 ./SerialPortDemo.apk SerialPortDemo-Signed.apk

The "signapk.jar", "platform.x509.pem" and "platform.pk8" files are available under the "android-platform-key-files" directory.

7.5 Step 5 Run & Debug

5.1) Install APK. Connect your board to a host PC with a microUSB cable and run adb commands to install your "SerialPortDemo-Signed.apk":

adb install SerialPortDemo-Signed.apk

5.2) Debug: After SerialPortDemo is started run the following command in "adb shell":

ps -Z

Check this com.friendlyarm.SerialPortDemo" process. If its right is as follows that means this application already has "system" right:

u:r:system_app:s0              system    1610  112   com.friendlyarm.SerialPortDemo

This case is for Android 4. If you do it under Android 5 it will be as follows. Although some details are slightly different it means the application has "system" right as well:

u:r:platform_app:s0            u0_a60    1905  138   com.friendlyarm.SerialPortDemo

If your application doesn't have "system" right it will fail to open a device.

8 Resources

9 Update Log

9.1 March-2-2017

  • Released English version

9.2 Dec-19-2017

  • Added section 5