Marine VHF Audio and Signalling Processor
CMX885
7.4
Device Control
The CMX885 can be set into many modes to suit the environment in which it is to be used. These modes
are described in the following sections and are programmed over the C-BUS: either directly to operational
registers or, for parameters that are not likely to change during operation, via the Programming register
($C8).
For basic operation:
1. Enable the relevant hardware sections via the Power Down Control register
2. Set the appropriate mode registers to the desired state (Audio, Inband, Data, etc.)
3. Select the required Signal Routing and Gain
4. Use the Mode Control register to place the device into Rx or Tx mode
To conserve power when the device is not actively processing an analogue signal, place the device into
Idle mode. Additional powersaving can be achieved by disabling the unused hardware blocks, however,
care must be taken not to disturb any sections that are automatically controlled.
See:
o
o
Powerdown Control – $C0 write
Mode Control – $C1 write
7.4.1 Signal Routing
The CMX885 offers a very flexible routing architecture, with three signal inputs, two separate signal
processing paths and two modulator outputs (to suit 2-point modulation schemes) and a single audio
output. Each of the signalling processing blocks can be independently routed from either of the Input
blocks, which can be routed from any of the three input signal pins. The audio/voice processing blocks
are always routed from Input 1. The outputs from signal processing blocks are determined by the settings
of the AuxADC and Tx MOD mode register in Tx mode.
See:
o
o
o
Input Gain and Output Signal Routing – $B1 write
AuxADC and Tx MOD Mode – $A7 write
Mode Control – $C1 write
© 2010 CML Microsystems Plc
16
D/885/3
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