RFXCOM RFXtrx433 Dokumentacja Pobierz pdf (Strona 43)

Chapter 4.

Implementation

This chapter deals with the implementation of the concepts as presented in the chapter 3.

4.1. Gateway

There are many diﬀerent suitable gateways on the market to connect both IT and HE to a com-

puter. However, the decision was easy because the author chose his own gateway, the WiﬁControl

433, which was developed in the student project "Implementation of an Ethernet gateway for wire-

less home automation". It has already been introduced in section 2.3 where we concluded that

it could be used out of the box and needs no changes for use in this work. This work represents

a good opportunity to revise the system and eliminate the existing limitations. First of all, the

gateway is brieﬂy introduced.

4.1.1. Brief technical introduction of WiﬁControl 433

The WiﬁControl 433 is a fully embedded platform for standalone use or use in conjunction with a

computer. Its core is the Atmel ATXMega192A3, an 8 bit RISC microcontroller with usable hard-

ware features, such as seven serial ports, three SPI ports and seven timers with 16 bit accuracy

It is connected to peripheral hardware, such as the WIFI module RN171, a real-time clock (RTC),

a serial-to-USB bridge and other diﬀerent hardware as shown in ﬁgure 4.1.

A so-called expansion port can be used for attaching external hardware and expand the functionality

of the platform. It consists basically of 22 outward conducted I/O pins, which are connected to a

pin header to make them more easily accessible. The expansion port can be programmed freely

and can provide external interfaces such as one SPI and three USART.

The ﬁrmware is written in C and kept very modular to be easy to maintain and modify. It is

composed of the program core for basic computing and several interrupt service routines (ISR) for

for further details on the microcontroller, visit http://www.atmel.com/devices/atxmega192a3.aspx

1 2 ... 38 39 40 41 42 43 44 45 46 47 48 ... 94 95

Brak uwag

RFXCOM RFXtrx433 Dokumentacja Strona 43