Controlling Protocol
Control of the functions and levels within the FX806A PLMR Audio Processor is by a group of Address/Commands and
appended data instructions from the system
µController
to set/adjust the functions and elements of the FX806A. The use of
these instructions is detailed in the following paragraphs and tables.
Command
Assignment
General Reset
Control Command
Mode Command
Mod. Levels Set
Volume Set
Address/Command (A/C) Byte
Hex
Binary
MSB
LSB
Command
Data
Table
01
10
11
12
13
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
1
0
1
+
+
+
+
1 byte
1 byte
2 bytes
1 byte
2
3
4
5
Table 1 “C-Bus” Address/Commands
In “C-BUS” protocol the FX806A is allocated Address/
Command (A/C) values 10
H
to 13
H
. “C-BUS” Command,
Mode, Modulation and Volume assignments and data
requirements are given in Table 1 and illustrated in Figure 5
(Main Block Diagram). Each instruction consists of an
Address/Command (A/C) byte followed by a data instruction
formulated from the following tables.
Commands and Data are only to be loaded in the group
configurations detailed, as the “C-BUS” interface recognises
the first byte after Chip Select (logic “0”) as an Address/
Command.
Function or Level control data, which is detailed in Tables 2,
3, 4 and 5, is acted upon at the end of the loaded instruction.
Upon Power-Up the value of the “bits” in this device will be
random (either “0” or “1”). A General Reset Command (01
H
)
will be required. This command is provided to “reset” all
devices on the “C-BUS” and has the following effect on the
FX806A.
Control Address Command
Mode Address Command
Volume Set
Loaded as 00
H
Loaded as 00
H
Loaded as 00
H
Control Command
Setting
MSB
Bit 7
0
1
6
0
1
5
0
1
4
0
1
3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
(Preceded by A/C 10
H
)
Control Bits
Transmitted First
Audio Output (Rx)
Disabled
Enabled
Modulation Drives
Disabled
Enabled
Pre-Emphasis
By-Pass
Enabled
Input Select
Rx Audio In
Mic. In
Input Level Set
Input Amp Disabled
-4.0dB
-3.0dB
-2.0dB
-1.0dB
0dB
1.0dB
2.0dB
3.0dB
4.0dB
5.0dB
6.0dB
7.0dB
8.0dB
9.0dB
10.0dB
Mode Command
Setting
MSB
Bit 7
0
1
6
0
1
5
0
1
4
0
1
3
0
1
2
0
0
0
0
1
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
(Preceded by A/C 11
H
)
Mode Bits
Transmitted First
Drive Source
Signals
Calibration
Deviation Limiter
Disabled
Enabled
VOGAD
Disabled
Enabled
De-Emphasis
Enabled
By-Passed
Signal Select
Internal
External
Process Gain Set
-4.0dB
-3.0dB
-2.0dB
1.0dB
0dB
1.0dB
2.0dB
3.0dB
Table 2 Control Commands
7
Table 3 Mode Commands
CMLMICRO [ CML MICROCIRCUITS ]
