The W65C265SXB 65xxcelr8r Board

I’m a software engineer working as a consultant for Chariot Solutions developing software solutions for clients to solve business problems. My path to becoming a software engineer started in hardware specifically integrated circuits while working at the Western Design Center (WDC) in the late 1980’s. It was at WDC where I learned how to layout circuits in a work-study program while studying Electrical Engineering at Arizona State University. Later, I changed majors and finished school with a B.S. in Computer and Information Sciences.
The last few years I’ve been focused on mobile applications primarily developing native Android applications. It’s very satisfying building apps that run on devices that you can hold in your hands. A refreshing change from building enterprise server-side software that runs on virtual machines in a cloud located somewhere on this planet. I still enjoy developing apps for mobile devices however, I find myself wanting to get back to my roots and get “closer to the metal”…to quote my Uncle Bill Mensch who taught me about integrated circuits years ago. Uncle Bill and I continue to stay in contact and have had many discussions on technology, philosophy, Embedded Intelligence, business, and family.
So, I’m one of 11 million professional software developers in the world today. My goal is to explore 65xx technology and share my experiences through the eyes of a software engineer. The first step starts with the W65C265SXB.

W65C265SXB Board

What is a W65C265SXB? The W65C265SXB (Standard chip Xxcelr8r Board) is a board designed for developing Hi-Rel (High Reliability) low-power applications for the W65C265S microcontroller. You can read about all the features of this board in the datasheet. WDC explained to me that their microcontrollers are general purpose making them ideal for use in industrial control systems, e.g. weigh belt conveyor systems, industrial refrigeration, access control, general communication, etc. The W65C265S is built on the 65xx Instruction Set Architecture (ISA), which is a very efficient ISA (benchmark comparison). Most microcontrollers today are RISC-based like the Atmel ATmega328 used in the popular Arduino Uno board. The difference in instruction set architectures is an important distinction. There are many RISC-based microcontrollers in the market however, there are only two (W65C134S & W65C265S) that are based on 65xx ISA.
The W65C265SXB is based around the W65C265S which is a feature rich 8/16–bit microcomputer based on the W65C816 microprocessor.
The first thing I did after unboxing my board was to plug in a USB cable into the J5 connector then into my MacBook Pro. Next, I downloaded the Python Terminal interface created by WDC. I had to make a few changes to the python script to run on my Mac since it was built to run on Windows. Finally, I ran the script and pressed the S1 reset button and …
Terminal Interface
…my board comes alive. 🙂 What you’re seeing is the initial output of the W65C265S internal Monitor ROM.
The monitor acts as a simple operating system, allowing the user to examine registers and memory, load and save programs, and debug applications in RAM.
The Monitor provides you with an interface into the mask ROM of the W65C265S. The Monitor was written in Assembly language (code listing) in the early 1990’s. As a software engineer, I find this pretty amazing that a simple operating system written in Assembly over 20 years ago can still be a valuable asset!
So my journey begins once again. I feel like it’s “back to the future” for me. It’s been 20 years since I last worked with 65xx technology. Now as I look at the W65C265SXB I wonder, can this technology still be relevant after all these years of technological advancement? I plan on finding out however, I bet I already know the answer. 😉

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