Apple II PT3 Vortex Tracker Library
Library for playing pt3 files generated by the
Vortex Tracker on an Apple II with Mockingboard.
This is an attempt to play some complex chiptune files on an old Apple II
with a Mockingboard card.
The Mockingboard, introduced around 1981, was a sound card for the Apple II
series of computers. It has dual AY-3-8910 chips on it, providing a total
of 6 channels of square-wave sound, plus noise and envelope effects.
My previous Chiptune Player played YM5 files,
which are raw captures of the AY-3-8910 data stream. These are easy to play,
but the raw data takes up a huge amount of space (hundreds of kilobytes)
when uncompressed. The chiptune player did some clever tricks with LZ4
compression to make things fit, but in the end most of the 48k of RAM on
an Apple II+ was needed to hold the ym5 file and decompressed register
This is coded in 6502 assembly language. And unlike my previous player,
you can drop properly named files onto the disk image and they should
play w/o any additional conversion.
Some technical details on the pt3 file format can be found here:
Some info on using the library can be found here:
Apple II Code/Disk Images
Using in Other Projects
Feel free to use this in your project! The code is dual licensed GPL2/BSD.
Some projects known to be using the code:
29 May 2021
Released version 0.3 which adds support for Apple IIc.
This does make the library slightly larger, so you can disable this
if constrained for space.
28 December 2019
Released version 0.2 which supports auto-detection of Mockingboard slot.
Other Apple2 Projects
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