NEC V60

Lore & Background

Development of the V60 began in 1982 under the leadership of Yoichi Yano, involving about 250 engineers. The processor debuted in February 1986 and entered full-scale production in August 1986. It was fabricated using a two-layer aluminum CMOS process with a 1.5 μm design rule, implementing 375,000 transistors on a single die. The V60 operated at 5 V and was initially packaged in a 68-pin PGA, with the first version running at 16 MHz and achieving 3.5 MIPS. Its sample price at launch was ¥100,000 ($588.23).

The V60 retained a CISC architecture described by NEC as having 'features of high-end mainframe and supercomputers,' with non-uniform-length instructions, memory-to-memory operations including string manipulation, and complex operand-addressing schemes. It operated as a 32-bit processor internally while externally providing 16-bit data and 24-bit address buses, and included 32 32-bit general-purpose registers. The processor also had the ability to emulate the earlier V20/V30 processors.

The V60 family included the improved V70 (1987) and V80 (1989) variants, all sharing the same instruction set architecture. The processors supported a Functional Redundancy Monitoring (FRM) mechanism for fault-tolerant systems, allowing multiple devices to operate in lockstep with master and checker modes, with selectable recovery methods for mismatched instructions.

Reader's Guide

The V60 family found applications across a wide range of fields, including circuit switching telephone exchanges, minicomputers, aerospace guidance systems, word processors, industrial computers, and various arcade games. Sega employed the V60 as the main CPU in its System 32 and Model 1 arcade architectures, and it was also used in the SSV arcade architecture developed jointly by Seta, Sammy, and Visco. Sega originally considered using a 16 MHz V60 for its Saturn console but ultimately chose a different design.

In 1988, NEC released a kit for Unix enthusiasts containing a V60 processor board for selected PC-9800 series models and a distribution of UNIX System V. NEC-group companies used the V60 in telephone circuit switchers and in word processor products for fast outline font processing. The V60's microcode variants were also employed in NEC's MS-4100 minicomputer series.

The V60/V70 instruction set architecture is emulated in the MAME CPU simulator, with open-source code available. The family was succeeded by the V800 product families, currently produced by Renesas Electronics. The V60's significance lies in its role as Japan's first 32-bit commercial microprocessor, its broad application spectrum from aerospace to arcade gaming, and its influence on NEC's subsequent processor lines.

Did You Know?

• The V60 was the first 32-bit general-purpose microprocessor commercially available in Japan.
• Sega considered using a 16 MHz V60 as the basis for its Saturn console before choosing a dual-SH-2 design.
• The V60 could emulate the earlier V20/V30 processors.