If you thought that the market for Personal Digital Assistant microprocessors was tied up by the US and the UK, then look a little further across the water to Japan. Two major Far Eastern players – NEC Corp and Hitachi Ltd – are preparing silicon offerings designed to put a dent in the American companies’ market share. Following the launch of the British ARM and American Hobbit RISC chips, and the deal between Intel Corp and VLSI Technology Inc to develop Personal Digital Assistant versions of the 80386SX, Hitachi and NEC are preparing the SH7000 and V800 chip families respectively. These processors, already significant in terms of power and cost, have even more importance strategically – they represent Japan’s first possible original success in the chip market for almost 20 years. Already shipping in Japan in volume since October last year, the NEC V800 series has been late getting to market in the UK and US, presumably while NEC waits for localised tool sets to be developed. The family will eventually encompass three chips the V805, V810 and V820. The 805 will be aimed at the low-cost market with a 16-bit external and 32-bit internal memory bus, while the 810 will have a full 32-bit architecture. The V820 will run at 33MHz, integrating more features including a serial port and Direct Memory Access control, which NEC hopes will bring it more in line with the action-packed Hitachi SH703x family. At the lower end, which will be available sooner, the family’s main characteristic is simplicity.

Trade-off

Unlike the Hitachi offering, the NEC chips aren’t feature-rich. What the chip loses in functionality, it presumably hopes to gain in price-competitiveness, and with a predicted selling price of just $20, the trade-off seems to work. The 810 has a floating point unit in addition to the CPU and 1Kb of instruction cache, but there is no hardware assistance for multiplying or dividing integers, slowing down maths operations. There are no peripherals or RAM on the chip, and designers wanting to connect it to these components externally – all of them, in other words – will need to implement extra glue logic and an external clock controller – all at extra cost. NEC’s chip has been given a basic 16-bit instruction size although there are some 32-bit ones. With 32 32-bit registers, it has twice as many as the Hitachi chip, although it takes two or more cycles to complete some branches, loads and stores. What the V810 chip sacrifices on features, it gains on power. Able to operate at 25MHz on 5V all the way down to 10MHz on 2.2V, the 810 can feasibly run on the 2.7V given out by two penlight batteries. According to NEC’s table, the V810 family offers better performance than the ARM while consuming less power. At 200 MIPS per Watt, the 2.2V version of the V810 will offer nearly 10 times as much mileage per gallon as the ARM 620-5V, and almost 100 times as much as Intel’s current 5V 80386DX. NEC’s table indicates a performance of roughly 18 MIPS for the 5V version, which slightly outweighs the Hitachi family’s 16 MIPS rating.

By Danny Bradbury

The lower end V805, which begins sample shipments this month, will reach volume in January next year. Only getting up to 20MHz at 5V, it attains a Dhrystone of 27,250 (13 MIPS) at that speed. The 820 chip will have a sleep mode although reports indicate that the 810 does not. In pitting the family directly against the Hobbit and ARM chips, NEC is challenging two companies with already strong links in the Personal Digital Assistant market. The technological features of these chips are as impressive as their strategic importance, too. The 32-bit RISC-based ARM 610 chip runs at a maximum 20MHz and can sustain up to 15 MIPS performance at this level. It has 4Kb of instruction cache and all of its instructions are 32-bit. The system includes a power down mode. The Hobbit is a 32-bit chip running on 3.3V at 20MHz, claiming a speed 185 times that of an 80486. It consists of a five-chip set, with other chips handling all the things that the V805 and V810 don’t, such as power management, memory cont

rol, clock generation and PCMCIA control. Attaining a steady performance of 13.5 MIPS, the chip has the advantage of being able to decode one instruction as it performs another, making it better at branch instructions. NEC is manufacturing its chips to 0.8 micron design rules, which is the same scale on which the ARM chip is fabricated. Advanced RISC Machines Ltd predicts that its foundries will take its chip fabrication operation to 0.6 microns by the end of the year, giving it a forecast 25% increase in performance. Still, not to be outdone, NEC plans to move its V810 fabrication process to 0.5 micron next year, giving it the power to run at up to 33MHz. Roughly 65% the size of an Hitachi SH chip, the V810 integrates 240,000 transistors under half those used by the Hitachi part. This is because the Hitachi chip includes on-board memory. NEC hasn’t released any more technical details than that in the UK. What is clear is that it has very high hopes for the chip. The company has stated that it wants to pick up 20% of the 32-bit Personal Digital Assistant market with the chip series. If the company pulls this off, it will be richly rewarded – with 240m adults in Europe alone, the potential market for the pocket devices is massive. NEC has a long way to go, though – by the time it ships its first chip in volume in the third quarter this year, AT&T’s Hobbit will have been in production for almost a year. Some ARM chips shipped even longer ago, in October 1991. NEC also faces the problem of gaining OEM partners to carry the chip forward. AT&T is using the Hobbit chip in its EO Personal Digital Assistant while the ARM610 has taken its place in Apple Computer Inc’s Newton product. The ARM’s other stronghold is of course with San Mateo, California-based company 3DO Co Inc which has announced that the ARM60 chip will be used in its specification for the Interactive Multiplayer product, to be available in the US in the autumn. Even so, NEC has an ally in Nintendo Co; the games console manufacturer is said to be planning to use the chips in its own CD-ROM unit, of which it hopes to ship 1m in the first year of production.

Prohibitive

NEC’s chip, already off the starting block in Japan, could well be the chip to attack the low-cost Digital Assistant market. What NEC must hope for, it seems, is that the estimated $20 OEM price for the chips manages to undercut its competitors. Hitachi will probably offer its chips at around $35 to $40, while you can pick up ARM 610s for $25 in volume. The other thing that NEC must hope for is that the winners and losers in the Personal Digital Assistant have not all made their choices yet. The EO Co Inc machines have not been around for long and their pricing is prohibitive at from $2,000 for a base unit. The Newton is not shipping yet, and neither are models based on the 3DO specification. Perhaps the V800 range will come across from Japan at a time when the market is starting to open up. Having waited for the big US players to blaze a trail, NEC can only hope.