Embedded Processor Watch

Editor: Tom Halfhill

In This Issue:

• Hitachi, ST Extend SuperH to 64 Bits
• Industry Resources: Living on Internet Time
• Embedded IC Announcements

Hitachi, ST Extend SuperH to 64 Bits

Building muscle without gaining fat -- it's the dream of every weight lifter, football player, and embedded-processor architect. In the last case, the goal isn't physical strength, but processing power without code bloat. That's what drove Hitachi Semiconductor and STMicroelectronics to collaborate on the SH-5, a 64-bit extension to Hitachi's SuperH architecture that's compatible with SuperH's svelte 16-bit instructions.

Hitachi's Jim Slager and ST's Jean-Marie Rolland described the new RISC architecture at last week's Microprocessor Forum. The SH-5 is a clever combination of power and efficiency that preserves existing investments in SuperH software. It also keeps Hitachi and ST in the accelerating race against other high-performance embedded processors, such as those based on PowerPC, MIPS, and StrongArm cores.

The first implementation will be a scalar core with dual 32K caches, dual TLBs, an integer/multimedia unit, an FPU, and a load/store unit. A high-speed on-chip bus known as the SuperHyway links the core to integrated peripherals on a system on a chip (SOC). Hitachi refers to this jointly designed core as the SH8000, while ST calls it the ST50. It's the foundation for a series of SOCs that each company will independently design, manufacture, and market. Based on simulations, Hitachi and ST expect SH-5 chips to execute 604 Dhrystone 2.1 MIPS, 2.8 GFLOPS, or 1.6 billion integer multiply-accumulate (MAC) operations per second at the target frequency of 400 MHz.

The SH-5 can execute all 208 instructions in the current SuperH instruction set, as well as 209 new instructions in the SH-5 instruction set. Thus, even though the new instructions are twice as long (32 bits), code expansion will be considerably less than 2x because programmers can freely mix the new instructions with older 16-bit instructions. No context switching is required because existing SuperH registers are mapped onto the much larger SH-5 register file (64 integer registers and 64 floating-point registers). Internally, SH-5 processors translate the old instructions into new instructions in an extra pipeline stage.

In addition to code density and backward compatibility, other strengths of the SH-5 are multivendor sourcing and excellent performance on floating-point and multimedia tasks. The SH-5 is well suited for set-top boxes that include gaming or 3D-graphics capabilities. It would be an even stronger contender if it appeared in 2000 instead of 2001. With so many competitors working on high-performance embedded processors, Hitachi and ST would be well advised to accelerate their production schedules.--T.R.H. (The full version of this article appeared in the October 6 issue of Microprocessor Report.)

Industry Resources: Living on Internet Time

The technologies behind the Internet are changing as rapidly as the Internet itself. Get up to date at Next Generation Networks, covering networking hardware and software in Washington, D.C., on November 1-5.

Learn about optical networking, implementing voice-over-IP, 10-gigabit Ethernet, building massive routers, and (one last chance) Y2K issues. The conference is sponsored by Business Communications Review and chaired by network pioneer and venture capitalist John McQuillan.

The three-day conference costs $1,795 to attend, or $2,295 including a Monday tutorial and Friday symposium. If you register by October 28, you'll get a free exhibit pass. For more information, go to http://www.ngn99.com.

Embedded IC Announcements

MCP2510 (Microchip Technology): an 18-pin interface controller with an industry-standard SPI serial interface; it also supports controller area network (CAN) specification 2.0B. It has interrupt capability, message masking/filtering, message prioritization, multipurpose I/O pins, and multiple transmit/receive buffers. Price: $3.25/1,000; available now. Call Microchip at 480.786.7668 or go to http://www.microchip.com/.

AD7741/AD7742 (Analog Devices): a pair of voltage-to-frequency converters (VFCs) with on-chip input buffers for high-input impedance, and with full-scale output frequencies up to 2.76 MHz. ADI says they are the first VFCs to guarantee 12-bit integral nonlinearity over the entire automotive temperature range (-40 to +105 degrees centigrade). They're intended for electric motor control, military radios, automotive GPS, cable modems, and battery-voltage monitoring. Prices: $2.33 to $2.86 each in 1,000-unit quantities; available now. Call ADI at 800.262.5643 or go to http://www.analog.com/.