[linux-audio-dev] strange MIDI messages when receiving programchanges ??

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Subject: [linux-audio-dev] strange MIDI messages when receiving programchanges ??
From: Benno Senoner (sbenno_AT_gardena.net)
Date: Mon Mar 20 2000 - 13:10:05 EET

Hi,
I have an old cheap master keyboard here
( branded Commodore :-) )

FYI: It supports running status
It has + / - keys for sending programchanges

plus keys from 0 to 9 for entering program changes
manually.

When I use the +/- keys all seems fine
only the program changes message are sent,

but when I use the numeric keys, the keyboards
seems to send PARAMETER messages along with
the program change:

keep reading below for a pratical example:
(read buf values in HEX)

programchange 01 using plus key (OK)

seq=1 read buf=c0
seq=2 read buf=01

programchange 02 using plus key (OK)

seq=3 read buf=c0
seq=4 read buf=02

programchange 02 using the "2" key (STRANGE)

first it sends 0xb0 , which is a PARAMETER message
followed by 2 bytes ( 0x00,0x00) which is
controller 0 with value 0
then 0x20 is sent: since bit 7 is 0 , it indicates
the running status mode (still PARAMETER message,
but without status byte)
0x20 is the first argument ( controller 32 (in decimal))
controller value 0
then finally the program change appears ( 0xc0 , 0x02)

seq=5 read buf=b0
seq=6 read buf=00
seq=7 read buf=00
seq=8 read buf=20
seq=9 read buf=00
seq=10 read buf=c0
seq=11 read buf=02

programchange using "3" key

seq=12 read buf=b0
seq=13 read buf=00
seq=14 read buf=00
seq=15 read buf=20
seq=16 read buf=00
seq=17 read buf=c0
seq=18 read buf=03

program change using "4" key

seq=19 read buf=b0
seq=20 read buf=00
seq=21 read buf=00
seq=22 read buf=20
seq=23 read buf=00
seq=24 read buf=c0
seq=25 read buf=04

Any thoughts ??

should I just ignore these PARAMETER messages ?
I looked at the midi controller table,
and controllers 0 and 32 do not have any special meanings.

Notice that the output above was produced using a simple
while loop reading 1 byte at time (blocking mode).

These tests were performed using an AWE64 + OSS/Free +
commodore MIDI masterkeyboard,
I think the read values are correct, and no loss of MIDI bytes
occurred.

Benno.

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