AMX AXB-MIDI User Manual

Page 16

Programming

AXB-MIDI MIDI Interface

The following table lists and describes System Common messages:

Channel Voice Messages (Cont.)

Status (D7---D0)

Data Bytes (D7---D0)

Description

1100nnnn

• 0ppppppp

• Program Change.

• This message sent when the patch number changes.

• (ppppppp) is the new program number.

1101nnnn

• 0vvvvvvv

• Channel Pressure (After-touch).

• This message is most often sent by pressing down on the

key after it "bottoms out". This message is different from
polyphonic after-touch. Use this message to send the single
greatest pressure value (of all the current depressed keys).

• (vvvvvvv) is the pressure value.

1110nnnn

• 0lllllll

• 0mmmmmmm

• Pitch Wheel Change.

• This message is sent to indicate a change in the pitch wheel.

The pitch wheel is measured by a fourteen bit value. Center
(no pitch change) is 2000H. Sensitivity is a function of the
transmitter.

• (llllll) are the least significant 7 bits. (mmmmmm) are the

most significant 7 bits.

System Common Messages

Status (D7---D0)

Data Bytes (D7---D0)

Description

11110000

• 0iiiiiii

• 0ddddddd

• 11110111

• System Exclusive.

• This message makes up for all that MIDI doesn't support.

(iiiiiii) is usually a seven-bit Manufacturer's I.D. code. If the
synthesizer recognizes the I.D. code as its own, it will listen
to the rest of the message (ddddddd). Otherwise, the
message will be ignored. System Exclusive is used to send
bulk dumps such as patch parameters and other non-spec
data. (Note: Real-Time messages ONLY may be interleaved
with a System Exclusive.)

• This message also is used for extensions called Universal

Exclusive Messages.

11110001

• Undefined. (Reserved).

11110010

• 0lllllll

• 0mmmmmmm

• Song Position Pointer.

• This is an internal 14 bit register that holds the number of

MIDI beats (1 beat=six MIDI clocks) since the start of the
song. l is the LSB, m the MSB.

11110011

• 0sssssss

• Song Select.

• The Song Select specifies which sequence or song is to be

played.

11110100

• Undefined. (Reserved).

11110101

• Undefined. (Reserved).

11110110

• Tune Request.

• Upon receiving a Tune Request, all analog synthesizers

should tune their oscillators.

11110111

• End of Exclusive.

• Used to terminate a System Exclusive dump (see above).