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
Page 2
D/7141_FI-3.x/6
CMLMICRO [ CML MICROCIRCUITS ]
