User manual

AOAA Kit – Software User’s Guide

Page 6

2 Introduction

Thank you for buying The Android™ Open Accessory Application Kit from Embedded Artists. For the

rest of the document the term Android Open Accessory will be written out as AOA. The kit (hardware

and software) will be called The AOAA Kit, for short. When referring to just the hardware the term

AOAA Board will be used.

The kit has been developed by Embedded Artists in close cooperation with NXP. It contains two

microcontrollers from NXP, the LPC1769 (Cortex-M3 core) and LPC11C24 (Cortex-M0 core). The two

microcontrollers are connected via a CAN network.

Embedded Artists’ AOAA Kit lets you get up-and-running with AOA experiments immediately. It is a

standalone platform for evaluation and prototyping electronic accessories for Google’s Android

operating system. The AOAA Board is also suitable for experimenting with CAN, Ethernet and RF

networks. The AOAA Board has been designed for evaluation and is not designed for final integration

into consumer or industrial end-products.

This document is a User’s Guide that primarily describes the software design of the AOAA Kit

demonstration applications. The hardware design is addressed in another document.

It is recommended that the reader has some basic knowledge about C programming and Android App

development. A good source for Android App development is the Android Developers Guide, see

reference [6].

2.1 Demo Applications – Overview

Android Open Accessory allows connecting Accessories to an Android device – typically a phone or

tablet. The Accessory and Android device communicates over USB. The Accessory has to implement

a USB Host interface, while the Android acts as a USB client (also called USB Device). For more

information about Android Open Accessory, see [3].

From a software perspective, this means that the Accessory must implement a USB Host interface.

There must also be two applications, one on the Accessory and one on the Android device. The two

applications communicate over a custom defined protocol. AOA leaves this protocol open. The

applications have complete freedom in defining the protocol between them and to create functionality

that supports the application in the best way.

Figure 1 – Basic Android Accessory Use Cases with Communication Protocol

Android

Accessory

Device

Android

Device

 Protocol between Android

device and Accessory.

 USB is only transport layer.

 Protocol is completely open for

definition and can be adapted

to specific requirements of the

applications.