AVM RS232 Programming Preset Messages (Class 3)
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AVM RS232 Programming Preset Messages (Class 3)
Message Details
Class 3: Audio Preset Message Details
The preset messages deal with information about the characteristics of specified
groups of audio
crosspoints
called presets. The AVM supports 64 separate audio presets.
Preset Name:
The name of an audio preset is a 16 byte ASCII string. If the name is less than 16 characters it must
be padded out (typically with spaces) to be 16 charaters long.
Ramp Time:
Every preset has a ramp time associated with it. The ramp time is the amount of time the matrix
takes to ramp to the preset values when the preset is invoked. There is only one ramp time for all
crosspoints in a preset. The ramp time can range from 0 to 30 seconds and is transmitted as two
unsigned bytes representing the time in milliseconds.
for output 1-8
bitmask = 1
for input = 1-8
no-change[input][output] = buffer[index] AND bitmask
bitmask = bitmask * 2
next input
index = index +1
next output
Input/Output Coordinates:
Presets are handled in 8X8 (64 byte) increments. The 8X8 section being manipulated is defined by
an input/output pair. Whatever 8X8 section contains the specified crosspoint is the section being
referenced. When a preset message is returned from the matrix, the i/o pair you sent will be trans-
lated into the upper left hand corner of the 8X8 section referenced. This calculation is carried out by
the matrix. For example if you send a
Get Audio Preset
message with the input output pair of 3,1,
the matrix translates this pair to 1,1 which is the beginning crosspoint on the 8X8 section containing
3,1. When the matrix sends you a
Audio Preset report
, the input/output pair will be reported as 1,1.
No-Change Mask:
Every preset includes a no-change mask. The mask is a bitmap that contains a single bit for every
crosspoint in the matrix. If the bit for a crosspoint 1 then that crosspoint is affected by the preset
when it is invoked. If the bit for a crosspoint is 0 then that crosspoint is not affected by the preset,
even though its corresponding value is non zero.
This feature allows the creation of presets that
affect only certain crosspoints while leaving others untouched. The values of the no-change bitmap
can be changed by using the
Set Preset Bitmap
and
Set Audio Preset Crosspoint
messages.
Format: The format of the no-change mask is a group of 8 bytes (with 8 mask bits per byte), which
covers an 8X8 section defined by an input/output pair. Byte #1 represents inputs 8-1 at output1, byte
2 represents inputs 8-1 at output 2, etc. Refer to the pseudo-code below, which reads the bitmap from
the
Audio Preset report
message.
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