Baseband Processor For Mixed Mode Land Mobile Radio
CMX880
$B0 ANALOGUE INPUT PATH CONFIGURATION: 16-bit write-only
Bit:
15
14
13
0
12
11
10
0
9
0
8
0
7
0
6
5
4
3
2
1
0
Input
Select
Data
Destination
Input
Gain
Audio Output
Attenuation
Bit 15
Bit 14
Input select
0
0
1
1
0
1
0
1
No input selected (ADC input º VBIAS
Microphone 1 (MIC1)
Microphone 2 (MIC2)
)
FM Discriminator (FMdisc)
Bit 12
Bit 11
Data destination
0
0
1
1
0
1
0
1
Internal only
Internal and “C-BUS”
Internal and FSB
Internal, FSB and “C-BUS”
Bit 6
Bit 5
Bit 4
Input Gain
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0dB
3.2dB
6.4dB
9.6dB
12.8dB
16.0dB
19.2dB
22.4dB
The input path provides a user programmable gain stage to amplify low power voice signals from the microphone
inputs, thus allowing a vogad facility to be implemented by software control. Finer gain control can be achieved
with the ‘FINE INPUT GAIN’ control register.
Bit 3
Bit 2
Bit 1
Bit 0
Audio Output Attenuation
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
>60dB
44.8dB
41.6dB
38.4dB
35.2dB
32.0dB
28.8dB
25.6dB
22.4dB
19.2dB
16.0dB
12.8dB
9.6dB
6.4dB
3.2dB
0dB
The output path provides a user programmable attenuation stage to adjust the volume of the audio output signal.
Finer volume control can be achieved with the ‘FINE OUTPUT GAIN 1’ control register.
Bits 7 to 10 and 13 reserved - set to 0.
ã 2001 Consumer Microcircuits Limited
43
D/880/1
CMLMICRO [ CML MICROCIRCUITS ]
