project Preface
What makes it run?
Interface Board

The aim of this board is to interact with the computers serial port and with a parallel connection to a weather device board (discussed later). The interface needs to operate independently of the computer. When referring to the interface board in the rest of the documentation it will be called METDEC, from the words METeorology DECoder.

A block diagram showing the interchange of the data is shown in Figure below.

Figure 1
Block Diagram
The main part of the interface is to collect the data and process it, this is done using a micro-controller, for the reasons stated before. The main reason for using a micro-controller other than a micro-processor is due to the size of the interface and the versatility of changing the program at ease. The interface board is therefore designed around the ATMEL AT89C52 micro-controller. To get the information from the board to the computer via the serial port, at the correct voltage, a MAX-232 chip is used to accomplish this. Memory is needed to record the data after processing is finished, so a suitable amount needs to be defined.
Project was completed in June 1995

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© 1995-1999 Andrew Lalchan