Decoding MIDI with discrete logic

Thomas Hudson thudson at cygnus.com
Fri Apr 30 23:24:58 CEST 1999


WeAreAs1 at aol.com wrote: 
>  What are some traps that I must watch out for?

Are you accounting for running status? If two identical messages are to be sent,
the status byte doesn't have to be sent for the second message. For example,

Continuous Controller
number
value
number
value
etc.

Secondly a single-byte system realtime can occur intermixed with any other
message, without reseting running status. So,

Continuous Controller
Sys Realtime
number
Sys Realtime
value
Sys Realtime
number
value
Sys Realtime
etc.

You could probably filter out the system realtime, but unless you have complete
control over the CC sending device, you will have to deal with missing status
bytes. 

The PAVO device mentioned in a previous post is the base platform from the book
"Digital Projects for Musicians" (Craig Anderton was a co-author). These devices
are pretty flexible and come with the midi parsing routines in ROM. I think what
you want to do is part of the base functionality, ie, would probably not require
additional programming.

Thomas



More information about the Synth-diy mailing list