Interfacing Keypad to MC-II Scientific Calculator: Hardware and Algorithm Documentation

Hi, I am building a scientific calculator and am documenting the project, covering hardware and algorithms. I have completed the chapter on interfacing to a graphical LCD and am now writing the chapter on interfacing to a keypad. The code is built in stages, making it easier to follow. The calculator is called MC-II and the manual and code are available here.

Hi Daniel -- I love calculators and knowing what goes on "under the hood." In fact, my book, How Computers Do Math, came with a CD containing a virtual calculator that runs on thereader's PC -- the books guides the reader in creating the assembly code to implement a simple four-function calculator.
Would you be interested in writing one or more articles about your project for EEWeb? If you want to bounce some ideas around, email me at max(_at_)clivemaxfield.com or call me on my office phone at 256-461-8333 (I'm in USA Central Time)

Hi Max, 
Me too, I've always been fascinated by calculators. As a matter of fact I read your excellent book in 2016 and it inspired me to keep going! This year I completed writing the firmware for the AriCalculator , a hand held calculator designed and made by Dirk Heisswolf (see main page and HP forum thread). I used BCD and CORDIC algorithms for the scientific functions, and the calculator is programmable as well. The firmware is written in 100% assembly for the NXP S12G microcontroller. I'm now porting the code to the  NXP S12XEP microcontroller, which is faster and has more memory. The instruction set is virtually identical so it's not too difficult. I've started writing a book on the project, and have just completed Part I covering hardware, software development tools and interfacing to the ST7565 graphical LCD and matrix keypads, and am starting Part II on algorithms. I tried to upload it today to my github page today but it exceeds the 25MB limit. I'll email it to you, and yes, I would be delighted to write articles about the project for EEweb.  

Part I, interfacing to a graphical LCD and matrix keypad, is complete. I used an ST7565 GLCD and am wondering if there are any colour GLCD's that people have used that they would recommend, 128x64 or larger?

Impressive, I am glad you're obtaining the structured program to be useful and that it is attending you get into programming! I suppose you are enjoying learning  assignment helpabout and developing software  

 graphical LCD and matrix keypads, and am starting Part II on algorithms. I tried to upload it today to my github page today but it exceeds the 25MB limit. I'll email it to you, and yes, I would be delighted to write articles about the project for EEweb.

I'm now using a colour display: Videos:https://www.youtube.com/watch?v=Ev7-7Hwkang
https://www.youtube.com/watch?v=rj_wxCEUXyc