CML Microcircuits
COMMUNICA
TION SEMICONDUCTORS
CMX7131/CMX7141
Digital PMR Processor
NXDN™ Operation
Advance Information
D/7141_FI-3.x/6 April 2014
DATASHEET
7131/7141FI-3.x: NXDN 4-FSK Baseband Data Processor with Auxiliary System
Clocks, ADCs and DACs
Features
4-FSK Modem
4.8 kbps Data Rate
Soft-decision Data Output Option
AFSD (Automated Frame Sync Detection)
AMBE+2 Vocoder, e.g. AMBE-3000
Tx Sequencer reduces host timing
constraints
Two RF Synthesisers (CMX7131 only)
Four Auxiliary ADCs (4 Multiplexed Inputs)
Four Auxiliary DACs
Two Auxiliary System Clock Outputs
Flexible Powersave Modes
Available in LQFP or VQFN Packages
Low-power (3.0 to 3.6V) Operation
C-BUS Serial Interface to Host µController
Vocoder Connectivity
Tx Outputs for Two-point or I/Q Modulation
Rx Inputs for CMX994 Direct Conversion
Receiver
RF Transmit
VCO Modulator
3.0V to 3.6V
RF Receive
Discriminator
or
Direct Conversion
Receiver
CMX7131/CMX7141
Digital PMR Processor
Built on
FirmASIC
®
Technology
Vocoder
CMX994
AMBE+2 Vocoder
Rx and Tx Enable
7131/7141FI-3.x
RF Synthesisers (CMX7131 only)
System clocks
GPIO
Reference clock
Tx PA ramp
DAC outputs
ADC inputs
NXDN™
C-BUS
Host µC
2014 CML Microsystems Plc
Digital PMR Radio Processor
CMX7131/CMX7141
1
Brief Description
The CMX7131/CMX7141 when loaded with 7131/7141FI-3.1 implements a half-duplex 4-FSK modem and
a large proportion of the NXDN Air Interface (physical) layer and Data Link layer. In conjunction with a
suitable host, voice coder and limiter/discriminator or CMX994 Direct Conversion (I/Q) Receiver based RF
transceiver, a compact, low cost, low power digital PMR radio conforming to the NXDN standard can be
realised. The 7131/7141FI-3.1.x has two receiver interface modes: Limiter/Discriminator (LD) mode is
selected by default for conventional limiter/discriminator receivers; I/Q mode is tailored for operation with
the CMX994 Direct Conversion Receiver IC. Dual mode, analogue/NXDN™ operation can also be
achieved by alternatively loading either 7031/7041FI-1 or 7131/7141FI-8 analog FM Function Images™.
The embedded functionality of the CMX7131/CMX7141 allows managing voice and data systems
autonomously. Host microcontroller interactions are minimised, enabling the lowest operating power and
therefore the longest battery life for a NXDN radio. The CMX7131/CMX7141 can also provide audio codec
functionality for vocoders under direct host control.
The device utilises CML’s proprietary
FirmASIC
component technology. On-chip sub-systems are
configured by a Function Image™: this is a data file that is uploaded during device initialisation and defines
the device's function and feature set. The Function Image™ can be loaded automatically from an external
serial memory or host µController over the built-in C-BUS serial interface. The device's functions and
features may be enhanced by subsequent Function Image™ releases, facilitating in-the-field upgrades.
This document refers specifically to the features provided by 7131/7141 FI-3.1.
Other features include two auxiliary ADCs with four selectable inputs and four auxiliary DAC interfaces
(with an optional RAMDAC on the first DAC output, to facilitate transmitter power ramping). The CMX7131
features two on-chip RF synthesisers, with easy Rx/Tx frequency changeover.
The CMX7141 is identical in functionality to the CMX7131, with the exception that the two on-chip RF
synthesisers have been deleted, which enables it to be supplied in a smaller package. This document
refers to both parts generically as the CMX7141, unless otherwise stated.
The device has flexible powersaving modes and is available in both LQFP and VQFN packages.
Note that text shown in
pale grey
indicates features that may be supported in future versions of the
Function Image™.
This Datasheet is the first part of a two-part document comprising Datasheet and User Manual: the User
Manual can be obtained from the CML Technical Portal by registering your interest in this product with
your local CML representative.
This datasheet is the first part of a two-part document
FirmASIC
®
and Function Image™ are trademarks of CML Microsystems Plc.
NXDN is a trademark of JVC KENWOOD Corp./ICOM Inc. Companies wishing to manufacture and brand NXDN radios must be
members of the NXDN Forum.
AMBE-3000 and AMBE+2 are registered trademarks of Digital Voice Systems, Inc.
2014 CML Microsystems Plc
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Digital PMR Radio Processor
CMX7131/CMX7141
CONTENTS
Section
1
2
3
4
Page
Brief Description ...................................................................................................................... 2
Block Diagram .......................................................................................................................... 7
Signal List................................................................................................................................. 8
3.1
Signal Definitions ........................................................................................................ 10
External Components............................................................................................................ 11
4.1
Recommended External Components ....................................................................... 13
4.2
PCB Layout Guidelines and Power Supply Decoupling .............................................. 14
4.3
CMX994 Interface ....................................................................................................... 16
General Description............................................................................................................... 18
5.1
Features...................................................................................................................... 18
5.2
System Design............................................................................................................ 19
5.2.1 Vocoder Implementation ...................................................................................... 19
5.2.2 Data Transfer ....................................................................................................... 20
5.2.3 RSSI Measurement (LD Mode only) .................................................................... 20
5.2.4 Serial Memory Connection (LD Mode only) ......................................................... 21
5.2.5 CMX994 Connection (I/Q Mode only) .................................................................. 21
5.2.6 Hardware AGC – AuxADC1 Connection .............................................................. 21
5.2.7 RSSI Measurement (I/Q Mode only) .................................................................... 21
5.3
Introduction ................................................................................................................. 22
5.3.1 Modulation ............................................................................................................ 22
5.3.2 Internal Processing .............................................................................................. 25
5.3.3 Frame Sync Detection and Demodulation ........................................................... 25
5.3.4 FEC and Coding ................................................................................................... 29
5.3.5 Voice Coding ........................................................................................................ 29
5.3.6 Radio Performance Requirements ....................................................................... 29
Detailed Descriptions ............................................................................................................ 30
6.1
Xtal Frequency............................................................................................................ 30
6.2
Host Interface ............................................................................................................. 30
6.2.1 C-BUS Operation ................................................................................................. 30
6.3
Function Image™ Loading.......................................................................................... 32
6.3.1 FI Loading from Host Controller ........................................................................... 33
6.3.2 FI Loading from Serial Memory ............................................................................ 35
6.4
NXDN Standard Vocoder Interface ............................................................................ 36
2
6.4.1 Support for I S Mode ............................................................................................ 36
6.5
Device Control ............................................................................................................ 36
6.5.1 General Notes ...................................................................................................... 37
6.5.2 Interrupt Operation ............................................................................................... 37
6.5.3 Signal Routing ...................................................................................................... 37
6.5.4 Modem Control..................................................................................................... 38
6.5.5 Tx Mode NXDN Formatted .................................................................................. 39
6.5.6 Tx Mode ............................................................................................................... 40
6.5.7 Tx Mode PRBS .................................................................................................... 44
5
6
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Digital PMR Radio Processor
CMX7131/CMX7141
6.5.8 Tx Mode Preamble ............................................................................................... 44
6.5.9 Tx Mode Mod Set-up............................................................................................ 44
6.5.10 Tx Mode Repeated Word ..................................................................................... 44
6.5.11 Tx Sequencer ....................................................................................................... 44
6.5.12 Rx Mode NXDN Formatted .................................................................................. 45
6.5.13 Rx Mode Raw ....................................................................................................... 45
6.5.14 Rx Mode Eye ........................................................................................................ 45
6.5.15 Rx Pass-through Mode ........................................................................................ 45
6.5.16 Rx Mode with CMX994 AGC (I/Q Mode only) ...................................................... 46
6.5.17 Rx Mode with CMX994 I/Q Cal (l/Q Mode only) ................................................... 46
6.5.18 Rx Mode with Powersave (I/Q Mode only) ........................................................... 46
6.5.19 Reset/Abort .......................................................................................................... 47
6.5.20 Data Transfer ....................................................................................................... 47
6.5.21 CMX994 Pass-through Mode ............................................................................... 48
6.6
NXDN Mode Operation ............................................................................................... 49
6.6.1 Frame Format ...................................................................................................... 49
6.6.2 Addressing ........................................................................................................... 51
6.6.3 Rx Mode ............................................................................................................... 51
6.7
Squelch Operation ...................................................................................................... 53
6.8
GPIO Pin Operation .................................................................................................... 53
6.9
Auxiliary ADC Operation ............................................................................................. 53
6.10
Auxiliary DAC/RAMDAC Operation ............................................................................ 54
6.11
RF Synthesiser (CMX7131 only) ................................................................................ 55
6.12
Digital System Clock Generators ................................................................................ 58
6.12.1 Main Clock Operation........................................................................................... 58
6.12.2 System Clock Operation ...................................................................................... 59
6.13
Signal Level Optimisation ........................................................................................... 59
6.13.1 Transmit Path Levels ........................................................................................... 59
6.13.2 Receive Path Levels............................................................................................. 59
6.14
Tx Spectrum Plots ...................................................................................................... 60
6.15
C-BUS Register Summary.......................................................................................... 61
7
Performance Specification ................................................................................................... 62
7.1
Electrical Performance ............................................................................................... 62
7.1.1 Absolute Maximum Ratings ................................................................................. 62
7.1.2 Operating Limits ................................................................................................... 63
7.1.3 Operating Characteristics..................................................................................... 64
7.1.4 Parametric Performance ...................................................................................... 70
7.2
C-BUS Timing ............................................................................................................. 71
7.3
Packaging ................................................................................................................... 72
Page
Definition of Power Supply and Reference Voltages........................................................ 10
Recommended External Components when using CMX994 ........................................... 17
SPI-Codec Format ........................................................................................................... 20
CMX994 Connections ...................................................................................................... 21
NXDN Frame Format – Audio Communication ................................................................ 26
NXDN Frame Format – Data Communication ................................................................. 27
Table
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
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Digital PMR Radio Processor
CMX7131/CMX7141
Table 7 NXDN Frame Format – Data Burst Operation ................................................................. 27
Table 8 Frame Types .................................................................................................................... 29
Table 9 Xtal/Clock Frequency Settings for Program Block 3 ........................................................ 30
Table 10 BOOTEN Pin States ....................................................................................................... 32
Table 11 NXDN Standard Vocoder Connections .......................................................................... 36
Table 12 Modem Mode Selection ................................................................................................. 39
Table 13 Modem Control Selection ............................................................................................... 39
Table 14 C-BUS Data Registers ................................................................................................... 48
Table 15 RxData 0/TxData 0 Block ID settings ............................................................................. 49
Table 16 C-BUS Registers ............................................................................................................ 61
Figure
Page
Figure 1 CMX7141 Block Diagram .................................................................................................. 7
Figure 2 CMX7141 Recommended External Components ........................................................... 11
Figure 3 CMX7131 Recommended External Components ........................................................... 12
Figure 4 CMX7141 Power Supply and Decoupling ....................................................................... 14
Figure 5 CMX7131 Power Supply and Decoupling ....................................................................... 15
Figure 6 CMX994 Interface ........................................................................................................... 16
Figure 7 NXDN Vocoder Connection ............................................................................................ 20
Figure 8 RSSI in I/Q Mode ............................................................................................................ 22
Figure 9 4-FSK PRBS Waveform – Modulation ............................................................................ 23
Figure 10 4-FSK PRBS Waveform – Spectrum ............................................................................ 23
Figure 11 Modulation Characteristics ............................................................................................ 24
Figure 12 Internal Data Blocks (LD Mode) .................................................................................... 25
Figure 13 Additional Internal Data Processing in I/Q Mode .......................................................... 25
Figure 14 FS Detection ................................................................................................................. 28
Figure 15 C-BUS Transactions ..................................................................................................... 31
Figure 16 FI Loading from Host .................................................................................................... 34
Figure 17 FI Loading from Serial Memory..................................................................................... 35
2
Figure 18 I S Mode Support .......................................................................................................... 36
Figure 19 Tx Data Flow ................................................................................................................. 43
Figure 20 Automatic Tx Sequencer............................................................................................... 44
Figure 21 Frequency Response for Rx Pass-through Mode ......................................................... 45
Figure 22 Rx Data Flow................................................................................................................. 52
Figure 23 AuxADC IRQ Operation ................................................................................................ 54
Figure 24 Example RF Synthesiser Components ......................................................................... 55
Figure 25 Single RF Synthesiser Block Diagram .......................................................................... 56
Figure 26 Digital Clock Generation Schemes ............................................................................... 58
Figure 27 Tx Modulation Spectra - 4800bps ................................................................................. 60
Figure 28 C-BUS Timing ............................................................................................................... 71
Figure 29 Mechanical Outline of 64-pin VQFN (Q1) ..................................................................... 72
Figure 30 Mechanical Outline of 64-pin LQFP (L9) ....................................................................... 72
Figure 31 Mechanical Outline of 48-pin VQFN (Q3) ..................................................................... 73
Figure 32 Mechanical Outline of 48-pin LQFP (L4) ....................................................................... 73
Information in this datasheet should not be relied upon for final product design. It is always recommended
that you check for the latest product datasheet version from the CML website: [www.cmlmicro.com].
2014 CML Microsystems Plc
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D/7141_FI-3.x/6
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