Mos6526

In order to create Commando 2084, I had to disassemble Commando. My original intention was to patch what was only needed and stop there. But I got carried away and I ended up analyzing and commenting the entire Commando code. The commented code (that can be recompiled to generate the exact original binary) is here: https://gitlab.com/ricardoquesada/c64-commando-2084/tree/orig Findings - Level 2 Apparently, the original idea was to ship Commando with 4 levels instead of 3. There is a lot of code/data that indicates that a “level 2” (the levels that are shipped with Commando are level 0, 1 and 3) was in progress, or even finished. ...

MOS 6526: The CIA chip You turn on your beloved SX-64 and you don’t see the blinking cursor. Don’t panic. Most probably one of the CIA chips (MOS 6526) is not working correctly. No blinking cursor. The Commodore 64 has two CIA chips. What you need to do is to replace the one that controls the keyboard, the CIA 1. But if you don’t know which one is CIA 1 and which is CIA 2, then you can either replace both, or do trial-and-error, or look at the IO schematics (hint: it is the one with the UB3 legend). ...