Changeset 1578

Timestamp:

06/20/09 22:46:03 (14 years ago)

Author:

jwoithe

Message:

MOTU: start documentation of the Cuemix protocol used in "Mark-3" devices. Protocol analysis by MG and GQ.

Files:

• trunk/libffado/doc/motu_firewire_protocol.txt (modified) (3 diffs)

trunk/libffado/doc/motu_firewire_protocol.txt

@@ -3 +3 @@
-
-Author: Jonathan Woithe
-3
+6
-
-
@@ -246 +246 @@
-
-
-
-
+ in pre-Mark3 models
+--------------------
-It has been noted that some mixer settings (particularly registers 0x4yyy)
-have been found to utilise "write enable" bits which when set allow their
@@ -329 +329 @@
- * In response the PC reads register 0x0c1c from the Motu to obtain the new
-   gain trim value and pad setting.
+
+
+Controlling Cuemix in Mark3 models
+----------------------------------
+With the introduction of the "Mark3" interface models (Ultralite, Traveler,
+828) MOTU completely changed the method used to control the Cuemix features
+of the interface.  This was partly out of necessity - with the additional
+Cuemix features being added to the "Mark3" models MOTU otherwise faced an
+unbounded expansion in the number of device registers needed.
+
+Protocol analysis of an Ultralite-mk3 was provided by MG and GQ.
+
+The Mark3 interfaces use a variation of a key-value protocol involving block
+writes to register device register 0x10000 (bus address ffc0-ffff-0001-0000
+nominally.  Either 2 or 3 quadlets are written depending on the message
+being sent.  For this documentation we will refer to the bytes within a
+message as b00 .. b11, with b00 being the first byte sent.
+
+Byte b00 and b01 form a heartbeat word.  Precisely how this is constructed
+is not currently known, but it seems it might just be a monotomically
+increasing number probably used by the device to detect missing data or
+something.
+
+Byte b02 seems to be some kind of class identifier.  Currently identified
+classes are:
+  0x66: Faders (including bus master), pan, input trim
+  0x69: Mute/Solo, Routing selection
+
+Specific message formats are described below.
+
+Trim: 3 quadlet message
+  b00-b01 - heartbeat
+  b02     - 0x66
+  b03     - channel select (0x00-0x09)
+  b04     - 0x02 (select trim control)
+  b05-b06 - unknown, TBA
+  b07-b10 - data (big endian float, 0.0 - 24.0)
+  b11     - 0x00
+
+Reverb send: TBA
+
+Channel faders: 3 quadlet message
+  b00-b01 - heartbeat
+  b02     - 0x66
+  b03     - bus select (0x00-0x09)
+  b04     - 0x03 (select fader control)
+  b05     - channel select (0x02-0x09)
+  b06     - 0x02
+  b07-b10 - data (big endian float, 0.0 - 1.0)
+  b11     - 0x00
+
+Pan: 3 quadlet message
+  b00-b01 - heartbeat
+  b02     - 0x66
+  b03     - bus select (0x00-0x09)
+  b04     - 0x02 (select pan control)
+  b05     - channel select (0x02-0x09)
+  b06     - 0x02
+  b07-b10 - data (big endian float, -1.0 - 1.0)
+  b11     - 0x00
+  
+Bus master fader: 3 quadlet message
+  b00-b01 - heartbeat
+  b02     - 0x66
+  b03     - bus select (0x00-0x09)
+  b04-b05 - 0x02-0x00 (select bus master control)
+  b06     - 0x02
+  b07-b10 - data (big endian float, 0.0 - 1.0)
+  b11     - 0x00
+  
+Bus routing: 2 quadlet message
+  b00-b01 - heartbeat
+  b02     - 0x69
+  b03     - output select (0x00-0x06, 0xff=disabled)
+  b04     - bus select (0x00-0x07)
+  b05-b07 - 0x00-0x00-0x02
+
+Mute: 2 quadlet message
+  b00-b01 - heartbeat
+  b02     - 0x69
+  b03     - state (0x00=disable, 0x01=enable)
+  b04     - bus select (0x00-0x07)
+  b05     - 0x00 (select mute control)
+  b06     - channel select (0x01=bus master, 0x02-0x0b)
+  b07     - 0x02
+
+Channel solo: 2 quadlet message
+  b00-b01 - heartbeat          
+  b02     - 0x69
+  b03     - state (0x00=disable, 0x01=enable)
+  b04     - bus select (0x00-0x07)
+  b05     - 0x01 (select solo control)
+  b06     - channel select (0x01=bus master, 0x02-0x0b)
+  b07     - 0x02
-
-