Gustavo Bitdinger & Rangarajan Rajagopalan
ECE 476 Spring 2005
Table of Contents
Our project was a real-time weather update system that accepted an airport code from the user via a keyboard, looked up the code on an internet database, and displayed the resulting weather information on a television screen.
We used the PS/2 protocol, between a standard keyboard and an Atmel Mega32 chip, to decode the airport code typed by the user. The keyboard only worked on a PS/2 protocol, explaining our decision to interface with it by reading data off of pin 3 of port D on the keyboard MCU. After receiving each character the user entered, the program keyboard.c sent the byte over the serial peripheral interface (SPI) to a second MCU running tv.c on a custom-built board. We used SPI because it made the most sense in this dual processor situation, where both chips were in close proximity with each other. The keyboard chip also sent complete airport codes over the UART to the personal computer running a program in Visual Basic (VB) to perform the internet query. Visual Basic .NET 2005 Beta provided functionality for serial communication, so it seemed like a sensible choice for the PC program. After the VB program obtained the weather data, it sent the information back over the UART to the keyboard MCU, which then used the SPI to convey the values to the custom board. The TV MCU then output the data in a readable fashion onto the tv screen.