Category: RC2018/04

One of the things I’m trying to do in this RetroChallenge is write a game for the Commodore CBM II series, while teaching myself Assembly. In my last update, I described the game engine I am working on, which is a sort of pseudo-3D FPS view mode (err, without the “S” part of FPS). As with just about any piece…

This is my 10th, and presumably final RetroChallenge update: tomorrow is the end of the contest. Most people would say “Hey, you were crazy to set that goal in the first place, let alone start with only a day left.” Ah, what do they know? I just a game design, and write some code. Sure, I only started learning assembly…

I do not remember how I debugged BASIC programs back in the 80s. To be honest, I do not even want to remember. I’m sure it was convoluted, ugly, and painful. You know what’s really nice? Modern development environments where you can step through your program, statement by statement, watch the variables change, maybe even change some yourself as you go,…

Last weekend we finished the PCB layout and sent it out for manufacturing. The PCB is 83x58mm and fits into a standard Commodore cartridge case. All the ICs are through holes except the DRAM chips. If everything goes well I will receive the boards sometimes next week, just in time for a final blog entry. PLD Code As mentioned in…

If you are following along from the last update, you now have assembled the pieces you need to start programming in 650x Assembly language. Since my RetroChallenge is focused on the Commodore CBM II (“B Series”) machines, I am going to be showing how to set a development environment for that machine. But the same environment will work just as…

  Assembly language: the very name strikes fear into the hearts of retro-computing oriented nerds everywhere. “I used to program my (Atari|Commodore|TI99|Apple|ZX Spectrum) in BASIC, and I always meant to do something in Assembly, but… ” If that sounds familiar to me, then this is the blog for you! Or rather, this is about the 100th blog for you, because…

A reminder to the hoards of fans who have been following along with bated breath each day for updates on this project: my goal for this, my first  RetroChallenge, is to get a CBM 710 into working state. My super ambitious goal would be to also write an assembly language program and get it running on the CBM 710. My…

In the last update, we discovered that the empty socket at highlighted item #2 was intended to hold the character ROM chip. In this update, I’m going to cover tracking down the contents of that ROM chip, the equipment we’ll need to replace the missing chip, and the basics of EPROM burning. Along the way, I’ll cover a couple more…

RC 2017/10 was my first retrochallenge. I reverse engineered the Berkely Softworks georam for Commodore 64/128 computers, published the design files and built a clone. For RC2018/04 I’d like to pick up where I left off and design a 4MB version of the ram expansion. The Berkeley Softworks geroam is a 512K memory expansion for the Commodore 64/128 originally designed…

Ok, I admit it: I lost a bit of focus the last few days. I should have been buckling down and describing the circuit board more, and well, working on getting the machine up and running. Instead I have been using my non-work, non-family time to… … program. In my defense, writing is hard work. “Programming is hard, too!”, you…