CMX989 Datasheet, PDF (1/31 Pages) CML Microcircuits – CDPD MAC and Data Pump Processor

CMX989
CDPD MAC and
Data Pump Processor
D/989/2 October 2001
Provisional Information
Features
Applications
• Reed-Solomon Encoder, Decoder and Error • CDPD (Cellular Digital Packet Data)
Correction
Terminals
• MAC and Physical Layer Functions:
• PCMCIA/PC-Card Wireless Modem
Minimize Host µController Burden and Power
Modules
• Tx and Rx Byte-Wide CDPD Frame FIFOs
• Wireless Internet Terminals
• Encapsulates/De-Encapsulates CDPD Frames • Portable and Mobile Wireless Data
to/from Over-Air Baseband Signals
Terminals
• Parallel Bus Hardware Interface to Host CPU • Line Power/Battery Applications
• 2.7V to 5.5V Supply, 28-Pin TSSOP Package • 19.2kbps (BT = 0.5) Full Duplex
GMSK Data Modems
1.1 Brief 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. 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. The Rx CDPD frame FIFO is automatically managed to wait for valid
synchronization to occur when first started and after lost signal recovery.
The 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).
© 2001 Consumer Microcircuits Limited