6502.org

Here's our sixth monthly roundup - see also our previous roundups and our profile page. Comments welcome on this thread! Check the original posts on gplus for comments too.


2015-06-05 Apple II disk low-level access: Prince of Persia bootloader and the "4am cracks" - stories of reverse-engineering the copy protection of some commercial games. The Woz Machine disk interface should be studied by everyone with an interest in minimal digital logic circuits! See Understanding the Apple II by Jim Sather - there's no controller IC, just a state machine ROM and a handful of 74 series. And a dual 555.


2015-06-12 Hans Otten's retrocomputing site - recently revamped and seen in this topic - well worth exploring so we've provided some links to get started.


2015-06-19 Acorn System 1 prototype, and other prototypes of interesting 6502 systems.


2015-06-26 Conway's Game of Life on 6502 - pointers to a few implementations but featuring a version in just 256 bytes.


Edit: fixup link rot

An early calculator display on the Acorn System 1 prototype! I have a nearly identical one here. I have often thought that type should be good for a minimal display that would be helpful in troubleshooting. They used to come in 4-digit sections like this one



(or apparently still do:)
which can be driven with a Maxim IC, or, if you don't mind timing the strobing in software, with a VIA. You could almost make a complete hybrid computer module in a 40-pin-DIP size and include one of those on it. I have some self-contained dot-matrix ones here from Avago that are about the same size but super expensive (like $35 for four characters!). You can feed them any set of four 5x7-dot patterns though. I don't know of any smaller display solution.

Yes those bubble displays are nice. Chris Chung uses three for his NP-25 RPN calculator gadget.
Seems very suitable for readout of hex digits. Or decimal digits.