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You are here: MIDI Drum Machine Firmware Overview

MIDI Drum Machine
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Circuit Board Layout
selected Overview
Code Listing
MIDI Protocol Details

8051 Assembly Language Source Code

This code is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose.

Download the code or browse an on-line copy.

This code is an original work by Paul Stoffregen, written in the Fall of 1991. This code has been placed in the public domain. You may use it without any restrictions. You may include it in your own projects, even commercial (for profit) products.

Code Overview

The overall operation of the code is a bit complex, because it services many sources of input using a combination of polling and interrupt handlers. Here is a flow chart that attempts to show how the code works:

flow chart diagram

TODO: Add some more explainations someday...

Memory Map

memory usage diagram

TODO: make a proper html table, instead of this gif image.

TODO: add some text that relates this stuff to a page about the drum machine's feature set.

The MIDI Drum Machine, Paul Stoffregen and Rod Seely.
Designed and constructed Fall, 1991. Project status: Complete.
Last updated: February 24, 2005
-- These drum-machine web pages are still under construction --
Questions, Comments?? <>