CMX989

Features:

Reed-Solomon Encoder, Decoder and Error Correction
MAC and Physical Layer Functions:Minimize Host µController Burden and Power
Tx and Rx Byte-Wide CDPD Frame FIFOs s
Encapsulates/De-Encapsulates CDPD Frames to/from Over-Air Baseband Signals
Parallel Bus Hardware Interface to Host CPU
2.7V to 5.5V Supply, 28-Pin TSSOP Package





Application

CDPD (Cellular Digital Packet Data) Terminals
PCMCIA/PC-Card Wireless Modem Modules
Wireless Internet Terminal
Portable and Mobile Wireless Data Terminals
Line Power/Battery Applications
19.2kbps (BT = 0.5) Full Duplex
GMSK Data Modems





Specifications






Description

The highly integrated CMX989 CDPD MAC and Data Pump Processor integrates complex CDPD MAC and physical layer functions to serve as a core engine for high performance, low power CDPD terminal designs. CMX989 MAC layer functions decouple the host CPU from the CDPD airlink to simplify and reduce CDPD protocol stack programming, free CPU capacity for applications, eliminate interface components, and allow CPU sleep time for power savings. Physical layer functions mate MAC layer to baseband radio signals with minimal host involvement. MAC and physical layer functions are intelligently coupled to meet airlink timing requirements. For example: Tx emissions automatically start in synchronisation with Forward Channel busy/idle status. CMX989 Rx CDPD frame FIFO is automatically managed to wait for valid synchronization to occur when first started and after lost signal recovery.
CMX989 radio interface supports simple, low cost, VCO-based RF modulators and discriminator-based receivers. Independent, programmable gain Tx outputs are provided for software trimming and balancing of modulating signals.
The host CPU interface is FIFO based and organized in CDPD frames, to provide a simple programming interface with low service latency requirements. Over-the-air frames are automatically encapsulated and de-encapsulated and include complete Reed-Solomon encoding, decoding and error correction, colour code insertion and related functions. Device status bits are accessible and may be individually configured to interrupt the host via the parallel hardware interface. The CMX989 operates from a 2.7V to 5.5V supply over -40 to 85°C and comes in a 28-pin TSSOP package (CMX989E1).