The Graphing Calculator – Explained

This is Team 5.2 explaining how our graphing calculator works. Our design is an USART based, interrupt driven device that generates mathematical input into a graphical output on the A3BU’s LCD screen.

In simple terms, it’s a calculator. That graphs. (Our team had a lot of trouble coming up with a name. Graphulator, The Graph Master, and Graphtastic Graphing Machine were all considered.)

Various interrupt methods were incorporated into the design through user character input and push buttons on the A3BU board. The input from the PC is parsed using our own developed parsing code, which gathers all possible outputs for a given range of inputs. The software then plots those on the LCD screen. The push buttons include various scaling and scrolling methods that allow the user to interrupt the program in order to horizontally and vertically scroll and/or scale, along with re-centering capabilities.

The hardware design is very similar to that of Lab 3, using a MAX232 chip to bridge communication between the PC and the LCD on the A3BU’s on-board USART. This is done in conjunction with a serial connection via RS-232 signals.