Specifications

physical layer was primarily based on one that is compatible with the microcontroller.

Important factors when deciding on a microcontroller and an operating system was for

their combination to provide enough power but also a flexible environment to develop

in. The selection of the microcontroller and the operating system it uses greatly affected

the overall cost of the system, so it was important to choose a solution that fulfilled the

requirements at the lowest cost.

4.2 The Hardware

A study of available technology was conducted on the internet to determine which

hardware solutions were available. Preference was taken to solutions that could

combine requirements, for example, a microcontroller with a network chip on the same

circuit board.

4.2.1 Network Hardware

Many varieties of physical layer integrated circuits are available from companies like

Rabbit semiconductors, Realtek and Crystal. The chips they produce can run at either

10Mbit or 100Mbit and act as the interface between the microcontroller and the

network. They all have a similar interface to the processor; therefore, their selection was

based on the microcontroller environment chosen and which one was commonly used to

interface with the controller.

4.2.2 The microcontroller

To decide on the microcontroller used it was important to consider how it interface with

a network physical layer controller and operate TCP/IP with its stack. It would be

possible to develop a TCP/IP stack, but due to time limitations it was decided that this

would only be required if a suitable version available at a suitable cost could not be

found. This TCP package would have to provide stack management functions and the

ability to control the network protocol layers. Then there is the possibility of running the

TCP environment built into a real time operating system. This would allow the ideal

development environment; development can focus on the MP3 player application layer