FRS Signalling Processor
CMX882
CONTENTS
Section
1.0
1.1
1.2
1.3
1.4
Page
Features........................................................................................................................2
Brief Description............................................................................................................2
Block Diagram...............................................................................................................8
Signal List .....................................................................................................................9
External Components .................................................................................................. 11
1.4.1 PCB Layout Guidelines and Power Supply Decoupling ................................... 12
1.4.2 Modulator Outputs .......................................................................................... 13
General Description..................................................................................................... 14
1.5.1 Sleep Mode and Auto Start Up........................................................................ 16
1.5.2 Auxiliary ADC ................................................................................................. 16
1.5.3 Receive Mode................................................................................................. 17
1.5.4 Transmit Mode................................................................................................ 25
1.5.5 FFSK/MSK Data Packeting............................................................................. 29
1.5.6 XTCSS Coding................................................................................................ 32
1.5.7 C-BUS Operation ............................................................................................ 34
C-BUS Register Description ........................................................................................ 35
Application Notes ........................................................................................................ 57
1.7.1 CRC and FEC encoding information ............................................................... 57
1.7.2 Data Interleaving............................................................................................. 58
1.7.3 Scrambler Seed Transfer ................................................................................ 58
Performance Specification........................................................................................... 59
1.8.1 Electrical Performance.................................................................................... 59
1.8.2 Packaging....................................................................................................... 69
Page
1.5
1.6
1.7
1.8
Table
Table 1 Voice Processing Combinations ................................................................................... 15
Table 2 Concurrent Rx Signalling Modes Supported by the CMX882 ....................................... 17
Table 3 CTCSS Tones ............................................................................................................. 20
Table 4 DCS Modulation Modes............................................................................................... 21
Table 5 DCS 23 Bit Codes ....................................................................................................... 22
Table 6 In-band Tones ............................................................................................................. 23
Table 7 Concurrent Tx Modes Supported by the CMX882 ........................................................ 25
Table 8 Data Frequencies for each Baud Rate ......................................................................... 29
Table 9 Maximum Data Transfer Latency................................................................................. 32
Figure
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Page
Block Diagram ............................................................................................................. 8
Recommended External Components ........................................................................ 11
Power Supply Connections and De-coupling .............................................................. 12
Modulator output components to achieve -100dB/decade roll-off................................ 13
Rx Audio Filter Frequency Response ......................................................................... 18
De-emphasis Curve for TIA/EIA-603 Compliance....................................................... 18
Low Pass Sub-Audio Band Filter for CTCSS and DCS ............................................... 19
2004 CML Microsystems Plc
6
D/882/7
CMLMICRO [ CML MICROCIRCUITS ]
