Cirrus unveils serial communications controllers

Electronic News, Sept 26, 1994

FREMONT, CALIF.--Cirrus Logic unveiled two serial communication controllers that support point-to-point protocol (PPP) to link distant LANs and create wide area network (WAN) webs via modem. The CL-CD2430 and CL-CD2431 are a tightly integrated controller solution designed to off-load the CPU and improve host performance, Cirrus claims.

The serial controllers set out to take advantage of today's faster V.32 modems and upcoming V.34 modems by providing four full-duplex serial channels. The CL-CD2430 supports seven clock/modem signals per channel and the CL-CD2431 supports 10 clock/modem signals. Both controllers support multiple protocols and can send and receive data at 115.2Kbps.

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The parts feature an embedded RISC processor, a 32-bit-address DMA with double buffers, on-chip FIFOs, vectored interrupts and protocol processing. Incorporating these features into the serial controller solution reduces host overhead and boosts performance.

The CL-CD2430 and 2431 were designed to respond to the proliferating networking market and its rising standards. Among the emerging needs are higher-performance equipment, more serial lines, greater throughput, support for various protocols and wider networks. Both are engineered for use in remote access equipment such as routers, servers and inverse multiplexers. Cirrus Logic data communications product marketing manager Mike Leung said refining existing technology to address these forces shaping future networks makes the most economical sense.

"We're not just providing a high-performance solution. We are also providing a low cost solution," Mr. Leung said. "That makes our chip very unique and desirable in these LAN applications."

The CL-CD2430 and CL-CD2431 controllers are packaged in 84-pin PLCC and 100-pin PQFP, respectively. Each chip is $28 in 1,000-unit quantities. Sample and production quantities are now available.

The two CL-CD2340, however, has already shown up a new series of remote-access asynchronous servers from Cisco Systems. Cisco's new Access Server family, aimed at branch office and corporate internetworking, is implemented with the Cirrus device and Motorola's MC68030 central processor to offer dial-up V.34 speeds for up to 16 ports/user simultaneously.

"We worked closely with Cisco to define the CL-CD243x specifications" stated Mr. Leung. Added Kevin Kennedy, Cisco's director of access products, "Cirrus Logic has definitely scored a win in the serial I/O arena with the CL-CD2430."