Marine VHF Audio and Signalling Processor
CMX885
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:
•
•
•
•
•
•
•
•
Analogue Output Gain register ($B0)
AuxADC and Tx MOD Mode register ($A7)
Input Gain and Signal Routing register ($B1)
Power Down Control register ($C0)
Tx Inband Tones register ($C3)
Tx Data registers ($CA & $CB)
Audio Tone register ($CD)
Interrupt Mask register ($CE)
8.1.19 Audio Control – $C2 write
15
Scra-
mble
14
13
12
11
10
9
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
0
Emph 12k5
25k
HPF
0
b15 Audio Scrambling Enable
b14 reserved
b13 Audio Pre/De-emphasis
b12 Audio 12.5kHz Filter Enable
b11 Audio 25kHz Filter Enable
b10 Audio 300Hz HPF Enable
0 = off
1 = enabled
0 = off
0 = off
0 = off
0 = off
1 = enabled5
1 = enabled
1 = enabled
1 = enabled
b9-0 reserved
8.1.20 Tx Inband Tones – $C3 write
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
twist
4
sgl
3
2
1
0
Tx DTMF Tone
b15-6
b5
b4
reserved, clear to 0.
DTMF Twist
DTMF Single Tone 0 = normal
0 = normal
1 = -2dB of twist applied to the lower DTMF tone.
1 = Single Tone, see Table 3 DTMF Tone Pairs
b3-0
DTMF tone value – see Table 3 DTMF Tone Pairs
See section 8.1.21.
8.1.21 Rx Data 1 – $C5 read
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Bit:
flag
DSC Character 0
flag
DSC Character 1
$C5
This word holds the most recent bytes (Byte 0 and 1) of DSC data decoded. Received data is continuous,
if the data is not read before the next data is received the current data will be over-written.
In DSC Formatted mode, if the flag bit (b15 or b7) is set, then the accompanying character has been
received with an error detected.
5
In order to pre-emphasise the FSK data, Program Block P0.0 bit 11 should be set.
© 2010 CML Microsystems Plc
44
D/885/3
CMLMICRO [ CML MICROCIRCUITS ]
