Embedded Processor Watch

Editor: Tom Halfhill

In This Issue:

• ARM9E Offers Improved DSP Performance
• Motorola Plugs PowerQuicc Gap
• Industry Resources: Attend Digital Design University
• New Embedded IC Announcements

ARM9E Offers Improved DSP Performance

To address the growing need for better signal-processing performance in high-volume system-on-a-chip applications -- such as mass-storage devices, cellular phones, and information appliances -- Arm has made another attempt to get it right. In 1996, Arm introduced a completely separate DSP core, Piccolo (see Microprocessor Report 11/18/96, p. 17). With its own instruction set, Piccolo has not become popular, due to the unconventional and complicated mechanism it uses to communicate and coordinate with an ARM processor.

This time, Arm has enhanced its existing ARM9 core (see Microprocessor Report 12/8/97, p. 10) with a new set of instructions and supporting hardware to improve signal-processing performance. The approaches used in the ARM9E are similar to those adopted by Hitachi, Lexra, and ARC for their DSP-enhanced cores. Today, Arm is not actively licensing Piccolo, because it believes the ARM9E is a better solution for medium-level signal-processing performance.

As a microcontroller, the ARM9 already has reasonable support for digital signal processing -- a Harvard memory architecture, a multicycle 32 x 32-bit multiply-accumulate (MAC) instruction, and conditional execution to minimize branch penalties. The ARM9E adds a 32 x 16 MAC unit (two-cycle latency with single-cycle throughput), saturating fractional arithmetic, and SIMD operations on packed 16-bit words to make more efficient use of the 32-bit data paths and ALUs.

New instructions in version 5 of the ARM architecture with Thumb DSP extensions (V5TE) include 32 x 16 and 16 x 16 MAC and multiply instructions as well as four fractional saturating arithmetic instructions. V5TE also includes CLZ, an instruction that supports faster normalization and division by counting leading zeroes. This instruction was first added to the ARM10 architecture that was introduced at last year's Embedded Processor Forum (see Embedded Processor Watch #23, http://www.MDRonline.com/q/epw/issues/epw_23.html).

Both LSI Logic and Lucent have licensed the ARM9E core. LSI has added the ARM9E to its CoreWare library and is targeting the mass-storage, digital-cellular, and voice-over-IP telephony markets. Lucent, which helped develop the core, is working with hard-drive manufacturers to create a single chip that integrates the ARM9E with Lucent's industry-leading read channel, disk-controller circuitry, and memory.

With the ARM9E, Arm is taking the right approach: adding new instructions to its already popular instruction set. This results in a much simpler unified programming model than the complicated microcontroller-plus-DSP programming model. It preserves a reasonable core size and power dissipation without impacting speed. The ARM9E, with its added benefits and minimal overhead costs, is well positioned to penetrate new application areas.--K.Y. (The full version of this article appeared in the June 21 issue of Microprocessor Report.)

Motorola Plugs PowerQuicc Gap

Nature abhors a vacuum, and Motorola abhors gaps in its embedded product line. For customers who need an under-$40 communications controller with Fast Ethernet but not USB or more than one multiprotocol serial interface, Motorola is sampling the new PowerQuicc MPC855T. It fills a price and features gap in the PowerQuicc line between the six-member MPC850 family and the eight-member MPC860 family (see Embedded Processor Watch #8, http://www.MDRonline.com/q/epw/issues/epw8.html).

The 855T has one 10/100-Mbit/s Ethernet port and one serial communications controller (SCC) that supports several interfaces and protocols: high-level data-link control (HDLC), multichannel HDLC, ATM segment and reassembly (SAR), Motorola's serial peripheral interface (SPI), inter-IC (I2C), and others. It also has a 4K instruction cache and a 4K data cache, and it runs at 50, 66, or 80 MHz. Prices range from $25 at 50 MHz to $32 at 80 MHz in 10,000-unit quantities.

Motorola expects the 855T to find its way into such products as cable modems, ADSL modems, small-office routers, and switching hubs for LANs. With more than 500 design wins for the PowerQuicc line -- and a customer list that includes Cabletron, Cisco, Fujitsu, Lucent, Marconi, Nortel, Motorola's own business units, and many others -- Motorola wants to cover every possible base with PowerQuicc variants.--T.R.H. (The full version of this article appeared in the July 12 issue of Microprocessor Report.)

Industry Resources: Attend Digital Design University

The University of California Berkeley Extension is offering a summer course in San Francisco that covers The ABCs of Digital Design. This three-day seminar, scheduled for August 2-4, provides an extensive overview of the fundamentals of IC design. Consultant Robert Hanson of AmeriCom Test will present the material. The course registration fee is $1,095. Other UC Berkeley Extension courses cover basic electronics, semiconductor fabrication, and high-speed PCB design. For more information, call 510.642.4151 or go to http://www.berkeley.edu/unex.

New Embedded IC Announcements

PIC16F873/874 (Microchip): a pair of 8-bit microcontrollers with 4K x 14 bits of flash memory and 128 bytes of E2PROM data memory; they can execute 5 MIPS at 20 MHz. Operating voltages range from 2.0 to 5.5 V. Both chips have a 10-bit A/D converter, an RS-485 UART, two 8-bit timers, and one 16-bit timer. Price: $7.39 to $7.99/1,000; production: now. Call Microchip at 602.786.7668 or go to http://www.microchip.com/.

MCPxxx family (Microchip): a family of six precision system-supervisor devices to support microcontrollers, ASICs, DSPs, and custom chip sets. They support embedded-control systems that need a system supervisor for power-on resets and brown-out detection. Price: $0.38/1,000; production: now. Call Microchip at 602.786.7668 or go to http://www.microchip.com/.

STLC3055 (STMicroelectronics): a single-chip Subscriber-Line Interface Circuit (SLIC) for short-loop telephone systems and ISDN terminal adapters that operates at a single positive supply voltage of 5.5 to 15.8 V, extending the life of emergency backup batteries in the event of a power failure. Price: $6.00/100,000; production: now. Call STM at 781.861.2650 or go to http://www.st.com.