CMX7032 and CMX7042 AIS Data Processor

Applications
Automatic Identification System (AIS) for Marine Safety
AIS Aids To Navigation (AtoN)
AIS Class B Transponders
AIS Rx-only or Tx-only Modules

Brief Description
A highly integrated baseband signalling processor IC, the CMX7032/CMX7042 fulfils the requirements of the class B marine Automatic Identification System (AIS) transponder market.
The AIS system allows ships and base stations to communicate their position and other data to each other without the need for a centralised controller. This allows vessels to "see" each other and take appropriate action to avoid collision and so improve marine safety. The system uses a GMSK 9600 baud data link in the Marine VHF radio band. The system requirements are defined in ITU-M 1371-1.
The CMX7032/CMX7042 is half duplex in operation, comprising two parallel Limiter-Discriminator Rx paths and one I and Q or two-point modulation Tx path. The Rx paths are configurable for AIS or DSC operation, the Tx for AIS only. The device performs signal modulation/demodulation with associated AIS functions, such as training sequence detection, NRZI conversion and HDLC processing (flags, bit stuffing/de-stuffing, CRC generate/check). Integrated Rx/Tx data buffers are also provided. This greatly reduces the processing requirements of the host μC. Provision of a number of auxiliary ADCs and DACs further simplifies the system hardware design, reducing the overall equipment cost and size.
The CMX7042 is identical in functionality to the CMX7032 with the exception that the two on-chip RF Synthesizers have been deleted, which enables it to be supplied in a smaller package. This document refers to both parts generically as the CMX7032, unless otherwise stated.
The CMX7032/CMX7042 devices utilise 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 EEPROM or from a host μController over the built-in C-BUS serial interface. The device's functions and features can be enhanced by subsequent Function Image™ releases, facilitating in-the-field upgrades. This document refers specifically to the features provided by Function Image™ 1.1.