CMX138 CML Microcircuits, CMX138 Datasheet - Page 46

• Manufacturer Part Number: CMX138
• Description: Audio Scrambler and Sub-Audio Signalling Processor
• Manufacturer: CML Microcircuits

Audio Scrambler and Sub-Audio Signalling Processor
9.1.12 Mode Control – $C1 write
b15
b14
b13-11
b10
b9
b8,7
b6
b5
b4-2
b1, b0
Changes to the settings of the bits in this register are implemented as soon as they are received over the
C-BUS (note that the C-BUS has a potential latency of up to 250μs).
In Tx mode, it is only permissible to select ONE of the following at any time:
It is essential that changes to the Program Register and the Audio Control register are completed before
entering Rx or Tx mode.
The following other registers or bits can be changed as appropriate (Note: not all possible changes are
appropriate), whilst the device is in Tx or Rx mode:
9.1.13 Audio Control – $C2 write
b15 Audio Scrambling enable
b14 Audio Compandor enable
b13 Audio Pre / De-emphasis
b12 Audio 12.5kHz Filter enable
b11 Audio 25kHz Filter enable
b10 Audio 300Hz HPF enable
b9, b8
© 2008 CML Microsystems Plc
scra-
mble
15
15
0
Audio Tone
In-band Tone
Audio
comp emph
14
14
reserved
Audio processing enable
reserved
Audio Tone enable
In-band Tone enable
reserved
CTCSS enable
DCS enable
reserved
Operational Mode
CTCSS Phase
13
•
•
•
•
•
•
•
•
13
0
Analogue Input Gain - $B0 write
AuxADC and TX MOD mode - $A7 write
Analogue Output Gain - $B1 write
Power Down Control - $C0 write
Tx In-band Tone - $C3 write
Audio Tone - $CD: 16-bit write-only
Scrambler Inversion Frequency – $CB write
Interrupt Mask - $CE write
12k5
12
12
0
25k
11
11
0
In-band modes
hpf
10
10
0
0 = off
0
0 = off
0
0 = off
0 = off
0
00
01
10
11
0 = off
0 = off
0 = off
0 = off
0 = off
0 = off
00
01
10
11
9
9
CTCSS
Phase
0 = off
IDLE
Rx
Tx
reserved
0 degrees (normal)
120 degrees
180 degrees
reserved
Page 46
8
8
0
1 = enabled
1 = enabled
1 = enabled
1 = enabled
1 = enabled
1 = enabled
1 = enabled
1 = enabled
1 = enabled
1 = enabled
7
7
0
sub audio tone number: CTCSS / DCS / none
1 = enabled
Sub Audio
6
6
mode
5
5
4
4
0
3
3
0
2
0
2
D/138_FI1.0/5
Idle / Rx / Tx
1
1
CMX138
0
0