National Semiconductor Corp is all set to revolutionise access to the IBM plug-compatible market with its single chip DP8344 biphase communications processor and transceiver (CI No 807) and the part has already had an impact on the market by being incorporated into Hewlett-Packard’s new 3270-type displays, which caused Telex Corp to downgrade its profit forecats after they were announced in August. The DP8344 BCP is designed to reduce the size and complexity of the equipment needed to encode, decode and process IBM 3270, 3299 and 5250 protocols. At just 41 square centimetres it can be added to cluster controllers, micros, terminals and printers as well as providing access to 370-class mainframes and IBM System 38, 36 and 34 machines. The DP8344 BCP, fabricated in CMOS, features a 20MHz, 50nS tri-state processor – that’s one that has on, off and control capabilities – and has an average instruction cycle time of 125nS. With its Harvard architecture it provides direct access to separate 64K of 16-bit instruction memory and 64K of 8-bit data memory and can operate stand-alone or with a remote processor. NatSemi reckons that up until now if a company wanted to emulate one of the IBM terminals, it would have to use a logic analyser to find out how the protocol had changed before it could develop new hardware and software. It claims that now, for the first time, the DP8344 allows the processor to be programmed thereby preserving the original design of the emulating terminal with only a few changes. This has been made possible by the configurability of the transceiver element which enables the processor to support IBM 3270/3299 co-ax, 5250 twin-ax and 8-bit protocols. Code can be customised with the built-in differential line receiver so that designers who use it can differentiate their products. In addition to its primary application, the DP8344 can be used as a gateway between a cluster controller and local area networks and can also provide access to mainframes by working as an IBM 3270 to-ASCII protocol converter. Alternatively it can be mounted on a communications card for a microcomputer expansion slot, enabling the micro to emulate a 3270 or 5250 terminal while keeping its distributed processing power. Shaken the competition Hewlett-Packard is already using the processor in its recently released HP 700/71 IBM 3191-compatible terminal that has so shaken up the competition in the 3270-compatible market with its rock-bottom price, and the part has passed alpha testing at various sites. NatSemi says it also has a range of development tools including an evaluation board, a monitor/debugger program and an IBM 3178 terminal emulation demonstration board. These can be bought from Capstone Technology of Fremont, California and HiLevel Technology Inc, Irvine, California. According to NatSemi pre-production devices in an 84-pin, surface-mount plastic leaded chip carrier are priced at $50 each in quantities of under 1,000. DP8344 is expected to be available with various processor speed options in the first half of 1988.
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