NEC

NEC Corporation (日本電気株式会社, Nippon Denki Kabushiki Gaisha) is a Japanese multinational provider of information technology (IT) services and products, with its headquarters in Minato, Tokyo, Japan. NEC provides IT and network solutions to business enterprises, communications services providers and to government agencies, and has also been the biggest PC vendor in Japan since the 1980s. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as just NEC. Its NEC Semiconductors business unit was one of the worldwide top 20 semiconductor sales leaders before merging with Renesas Electronics. NEC is a member of the Sumitomo Group.

History

1898 to 1919

Kunihiko Iwadare and Takeshiro Maeda established Nippon Electric Limited Partnership on August 31, 1898 by using facilities that they had bought from Miyoshi Electrical Manufacturing Company. Iwadare acted as the representative partner; Maeda handled company sales. Western Electric, which had an interest in the Japanese phone market, was represented by Walter Tenney Carleton. Carleton was also responsible for the renovation of the Miyoshi facilities. It was agreed that the partnership would be reorganized as a joint-stock company when treaty would allow it. On July 17, 1899 the revised treaty between Japan and the United States went into effect. Nippon Electric Company, Limited was organized the same day with Western Electric Company to become the first Japanese joint-venture with foreign capital. Iwadare was named managing director. Ernest Clement and Carleton were named as directors. Maeda and Mototeru Fujii were assigned to be auditors. Iwadare, Maeda and Carleton handled the overall management.

Floppy-disk controller

A floppy-disk controller (FDC) is a special-purpose chip and associated disk controller circuitry that directs and controls reading from and writing to a computer's floppy disk drive (FDD). This article contains concepts common to FDCs based on the NEC µPD765 and Intel 8272A or 82072A and their descendants, as used in the IBM PC and compatibles from the 1980s and 1990s. The concepts may or may not be applicable to, or illustrative of, other controllers or architectures.

Overview

A single floppy-disc controller (FDC) board can support up to four floppy disk drives. The controller is linked to the system bus of the computer and appears as a set of I/O ports to the CPU. It is often also connected to a channel of the DMA controller. On the x86 PC the floppy controller uses IRQ 6, on other systems other interrupt schemes may be used. The floppy disc controller usually performs data transmission in direct memory access (DMA) mode.

The diagram below shows a floppy disc controller which communicates with the CPU via an Industry Standard Architecture (ISA) bus. An alternative arrangement which is more usual in recent designs has the FDC included in a super I/O chip which communicates via a Low Pin Count (LPC) bus.

Numerical Electromagnetics Code

The Numerical Electromagnetics Code, or NEC, is a popular antenna modeling system for wire and surface antennas. It was originally written in FORTRAN in the 1970s by Gerald Burke and Andrew Poggio of the Lawrence Livermore National Laboratory. The code was made publicly available for general use and has subsequently been distributed for many computer platforms from mainframes to PCs.

NEC is widely used for modelling antenna designs, particularly for common designs like television and radio antennas, shortwave and ham radio, and similar examples. Examples of practically any common antenna type can be found in NEC format on the internet. While highly adaptable, NEC has its limits, and other systems are commonly used for very large or complex antennas, or special cases like microwave antennas.

By far the most common version is NEC-2, the last to be released in fully public form. There is a wide and varied market of applications that embed the NEC-2 code within frameworks to simplify or automate common tasks. Later versions, NEC-3 and NEC-4, are freely available as compiled binaries but have not been nearly as popular.

NEC µPD7720

The NEC µPD7720 is the name of fixed point digital signal processors from NEC (currently Renesas Electronics). Announced in 1980, it became, along with the Texas Instruments TMS32010, one of the most popular DSPs of its day.

Background

In the late 1970s, telephone engineers were attempting to create technology with sufficient performance to enable digital touch-tone dialing. Existing digital signal processing solutions required over a hundred chips and consumed significant amounts of power.Intel responded to this potential market by introducing the Intel 2920, and integrated processor that, while it had both digital-to-analog and analog-to-digital converters, lacked additional features (such as a hardware multiplier) that would be found in later processors. Announcements for the first "real" DSPs, the NEC µPD7720 and the Bell Labs DSP-1 chip, occurred the following year at the 1980 IEEE International Solid-State Circuits conference. The µPD7720 first became available in 1981 and commercially available in late 1982 at a cost of $600 each. Beyond their initial use in telephony, these processors found applications in disk drive and graphics controllers, speech synthesis and modems.

NEC V60

The NEC V60 (μPD70616) was a CISC processor manufactured by NEC starting in 1986. The V60 was the first 32-bit general-purpose microprocessor commercially available in Japan.

A relatively obscure design in the West, it was a radical departure from NEC's previous V-series CPUs—the NEC V20-V50 series—, which were based on the Intel x86 model, although it retained the ability to emulate them. According to NEC's documentation, the architectural change was made due to the increasing demand and diversity of programs, calling for a processor with both power (the 32-bit internal bus) and flexibility, having large numbers of general-purpose registers—a common feature of RISC architectures and a benefit to the emerging high-level languages. The V60 architecture retained however CISC features (which its manual describe as mainframe-based) like variable-length instructions, memory-to-memory operations including string manipulation, and fairly complex operand addressing schemes.

Although it had a 32-bit internal bus, the V60 had only a 16-bit external data bus and a 24-bit address bus. Its architecture was carried largely intact to the V70 (μPD70632) model, which had external 32-bit buses and was released in 1987. Launched in 1989, the V80 (μPD70832) was the culmination of the series having on-chip caches, a branch predictor, and less reliance on microcode for complex operations. The V60-V80 architecture did not enjoy much commercial success.

NEC V25

The NEC V25 (µPD70320) is the microcontroller version of the NEC V20 processor. Features include:

It was officially phased out by NEC in early 2003