NEC V20

NEC V20, 8MHz.

The NEC V20 (μPD70108) was a processor made by NEC that was a reverse-engineered, pin-compatible version of the Intel 8088 with an instruction set compatible with the Intel 80186. The chip featured approximately 29,000 transistors, ran at 8 to 16 MHz and was around 30% faster (application dependent) than the 8088 at the same clock speed, primarily due to a hardware multiplier (whereas the 8088 had to perform multiplication using a microcode program). NEC V20 was used in "turbo" versions of some PC clones such as Commodore PC compatible systems, Copam, and Tandy 1110 laptop series. It was also used in the Casio PV-S450 PDA and Hewlett-Packard's HP 95LX. Sony also produced this microprocessor under license from NEC as the V20H (Sony CXQ70108).

An unusual feature of the NEC V20 was that it added an Intel 8080 emulation mode, in which it could execute programs written for the Intel 8080 processors. The instructions BRKEM executed in 8086 mode (NEC used a different notation for the instructions than Intel and BRK in NEC notation = INT in Intel notation) and RETEM and CALLN executed in 8080 mode was used to switch or return to or from the emulation mode. There was a V2080 CPMulator program which allowed to run 8080-based CP/M-80 programs on a MS-DOS machine.

NEC V30, 10MHz.

The NEC V30 (μPD70116) was a version of the NEC V20 that was pin compatible with the 16-bit data bus Intel 8086 processor. It too supported the 8080 emulation mode. The V30 was used in the GTD-5 EAX Class 5 central office as a drop-in performance upgrade for the processor complex in the late 1980s. It was also used in the Psion Series 3, in the NEC PC-9801, the Olivetti PCS86, the Applied Engineering "PC Transporter" emulator for the Apple II series of computers, and in various arcade machines (particularly ones made by Irem) in the late 1980s.

The NEC V20HL (μPD70108H) and NEC V30HL (μPD70116H) were a high-speed (up to 16MHz) and low-power versions.

The NEC V25 is the microcontroller version of the NEC V20 processor.

The NEC V33 is a super version of the V30 that separates address bus and data bus, and executes all instructions with wired logic instead of micro-codes, making it twice as fast as a V30 for the same clock frequency. V33 has the performance equivalent to Intel 80286. NEC V33 offers a method to expanding the memory address space to 16M bytes. It has two additional instructions BRKXA and RETXA to support extended addressing mode. The 8080 emulation mode was not supported.

The NEC V33A (μPD70136A) differs from the NEC V33 in that it has interrupt vector numbers compatible with intel 80X86 processors.

NEC V40

NEC V40 (μPD70208) embedded version of V20, integrated Intel-compatible 8251 USART, 8253 programmable interval timer, and 8255 parallel port interface. Used in the Olivetti PC1.

NEC V50 (μPD70216) embedded version of V30 with 16-bit data bus.

The NEC V41 (μPD70270) NEC V51 (μPD70280) integrated V30HL core and PC-XT peripherals: 8255 parallel port interface, 8254 programmable interval timer, 8259 PIC, 8237 DMA controller and 8042 keyboard controller. Also integrates full DRAM controller. Was used in Olivetti Quaderno XT-20.

The NEC V53 (μPD70236) integrates a V33 core with 4-channel DMA (μPD71087/i8237), UART (μPD71051/i8251), three timer/counters (μPD71054/i8254) and interrupt controller (μPD71059/i8259).

V53A(uPD70236A)

The NEC V53A (μPD70236A) integrates some peripherals with a V33A core.

The Vadem VG230 was a single-chip PC platform. The VG230 contained a 16 MHz NEC V30HL processor and IBM PC/XT-compatible core logic, LCD controller (CGA/AT&T640x400) with touch-plane supprt, keyboard matrix scanner, dual PCMCIA 2.1 card controller, EMS 4.0 hardware support for up to 64 MB, and built-in timer, PIC, DMA, UART and RTC controllers. It was used in the HP OmniGo 100 and 120.

The enhanced Vadem VG330 contained a 32 MHz NEC V30MX processor and IBM PC/AT-compatible core logic with dual PICs, LCD controller (640x480), keyboard matrix scanner, PC Card ExCA 2.1 controller and SIR port.

Starting with the NEC V60, NEC departed from the x86 design.

See also

• CPMulator

External links

• Casio FZ-1 information
• Information from cpu-collection.de
• the V20 at CPU-World

This computer hardware article is a stub. You can help Wikipedia by expanding it.v · Categories: NEC x86 microprocessors Computer hardware stubs Wikimedia Foundation. 2010. Игры ⚽ Поможем написать курсовую Forever Young (album) USS Briscoe (DD-977) Look at other dictionaries: NEC V20 — NEC V20. El NEC V20 (μPD70108) fue un microprocesador hecho por NEC que tenía aproximadamente 29.000 transistores. Fue desarrollado utilizando ingeniería inversa y era compatible pin a pin con el microprocesador Intel 8088, además su conjunto de… …   Wikipedia Español NEC V20 — Der NEC V20 (µPD70108) war ein zum Intel 8088 pin kompatibler Prozessor, der durch reverse engineering hergestellt wurde und einen zum Intel 80186 kompatiblen Befehlssatz besaß. Die zirka aus 29.000 Transistoren bestehende CPU lief mit 8 16 MHz… …   Deutsch Wikipedia NEC V20 — (μPD70108) 16 битный микропроцессор, разработанный компанией NEC, содержащий приблизительно 29000 транзисторов. Является аналогом процессора Intel 8088, совместим с ним по расположению выводов, работает …   Википедия NEC V20 — El NEC V20 fue un procesador hecho por NEC que tenía aproximadamente 29.000 transistores. Era una versión del microprocesador Intel 8088 desarrollada usando ingeniería inversa. El conjunto de instrucciones era compatible con la Intel 80186 que… …   Enciclopedia Universal NEC V20 — Le NEC V20 est un microprocesseur fabriqué par NEC Corporation [Quand ?]. Il comporte approximativement 29 000 transistors. C est une version du processeur Intel 8088 réalisée en ingénierie inversée qui fonctionne de 8 à 10 MHz. Sa… …   Wikipédia en Français NEC V30 — NEC V20. Der NEC V20 (µPD70108) war ein zum Intel 8088 pin kompatibler Prozessor, der durch reverse engineering hergestellt wurde und einen zum Intel 80186 kompatiblen Befehlssatz besaß. Die zirka aus 29.000 Transistoren bestehende CPU lief mit 8 …   Deutsch Wikipedia NEC V25 — NEC V25. The NEC V25 is the microcontroller version of the NEC V20 processor. Features include: NEC V20 core: 8 bit external data path, 20 bit address bus Timers Internal interrupt controller It was officially phased out by NEC in early 2003 …   Wikipedia NEC Corporation — Rechtsform Corporation ISIN JP3733000008 Gründung 1899 …   Deutsch Wikipedia V20 — or V 20 may refer to:* V20 engine * NEC V20 microprocessor …   Wikipedia NEC V60 — The NEC V60 (μPD70616) was a CISC processor manufactured by NEC introduced in the late 1980s. It had a 32 bit internal bus and a 16 bit external bus with a 24 bit address bus. A relatively obscure design, it was a radical departure from NEC s… …   Wikipedia 18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”