Re: Any sysex masters out there?
Posted by Joe on June 11, 1999 at 23:39:49:
In Reply to: Any sysex masters out there? posted by Joakim on June 11, 1999 at 17:47:23:
: The QS sysex doc availble from alesis' site says that a midi edit message should be 12 bytes but theres only 11 bytes in the example.
I suspect the "12 MIDI bytes" is a misprint. It could be an artifact of trying to account for the packed format of the MIDI data (i.e. 7 bytes of MIDI data occupy 8 bytes of a sysex message because the most significant bit of all data bytes must be 0). This is described in a rather cryptic way in the description for opcode 00 (MIDI User Program Dump). I would trust the example.
:The document also says that you should pay attention to the QS family ID byte. Why???
As you (should) know, bytes 1, 2, and 3 of any sysex message contain the manufacturer's ID code. (Alesis' is 00 00 0E). The next byte (4) is used by Alesis to identify which of their products the sysex is intended for. The QS series of synths has a family ID byte of 0E. Other Alesis products will have different family ID bytes (e.g the SR-16 drum machine uses a value of 05). This lets devices receiving a sysex message tell if it was meant for them or some other device. Using different family ID values allows devices to ignore messages not intended for them.