User manual

LPCXpresso Experiment Kit - User’s Guide
Page 137
Copyright 2013 © Embedded Artists AB
8.11 Registry in E2PROM
Create a so called registry, which is a non-volatile storage that can store values connected to so called
keys. Non-volatile storage is easily created by using the E2PROM, which is accessible over the I2C-
bus. The keys can be short strings, for example strings with lengths between 1 and 16. To make it
simple, a value connected to a key is always a 32-bit integer.
If you want to make it more advanced, a value can also be a string.
Typical operations for a registry are:
 Create entry for a new key
 Delete key
 Get value of key
 Update key
 List all keys
A registry is always usable to have when creating real-world applications. There is often a need to
store settings from a user. Also in the case of Internet communication the following settings must be
stored in the system:
 IP address
 Subnet mask
 Default gateway
 If an Ethernet interface is present, the MAC address is also needed
8.12 Real-Time Dynamic Data with JAVA Applet
This is a project that requires a TCP/IP stack, web server and RTOS.
By using SSI and CGI/EGI technologies (in a web server) you can create dynamic information in a web
server. However, the information is created at the download moment. Anything that happens after that
point in time will not be reflected on the client side. True real-time data visualization is hence not
possible with SSI or CGI/EGI.
To create true real-time data on the client side (= the web browser) a JAVA applet must be used. The
JAVA applet connects back to the embedded system, opens a communication channel, and then
received real-time data. The communication channel can be either a TCP or a UDP connection.
There must of course be a TCP/UDP server on the system that produces the real-time data. It is this
server that the JAVA applet connects to. Create such a system!
Let the server produce a stream of data, for example a sinus-valued signal stream. Alternatively, the
server can stream the values from both analog inputs of the board. Let the JAVA applet display this
data stream in a suitable way.
8.13 Multiplayer Game via RF-module
Create a multiplayer game with the help of RF-modules. For example ping-pong on a graphical display.
8.14 Home Alarm System
Create a home alarm system with remove sensors that communicate wirelessly with a central. It can
even communicate with a GSM/3G phone modem and make a call/send an SMS in case of an alarm.