Bill Mensch

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Bill Mensch
Bill Mensch - Western Design Center (12924524534).jpg
Mensch in 2014
Born (1945-02-09) February 9, 1945 (age 79)
NationalityAmerican
Education B.S.; University of Arizona
A.S.; Temple University
Occupation Microprocessor designer
Known for Motorola 6800
MOS Technology 6502
Western Design Center

William David Mensch, Jr. (born February 9, 1945) is an American electrical engineer born in Quakertown, Pennsylvania. He was a major contributor to the design of the Motorola 6800 8-bit microprocessor and was part of the team led by Chuck Peddle that created the MOS Technology 6502. He also designed the 16-bit successor to the 6502, the 65816. [1]

Contents

Mensch is the founder, chairman, and chief executive officer (CEO) of the Western Design Center (WDC) located in Mesa, Arizona. Before founding WDC in 1978, Mensch held design engineering and management positions at Philco-Ford, Motorola, MOS Technology, and Integrated Circuit Engineering. [2] At WDC, Mensch worked mainly on extending and expanding the 6502 architecture. His designs are used widely in embedded systems and implantable, electronic, life-support devices.[ citation needed ]

Education, teaching and honors

Mensch graduated with an associate degree (A.S.) from Temple University in 1966 where he was a member of Sigma Pi fraternity. [3] He received his Bachelor of Science (B.S.) degree in electrical engineering from the University of Arizona in Tucson in 1971. He has taught classes at Arizona State University, including courses on system on chip (SoC) integrated circuit (IC) design. Mensch is a Senior Member of the Institute of Electrical and Electronics Engineers (IEEE). In 2004, he was inducted in the Computer Hall of Fame (hosted by the San Diego Computer Museum, part of the San Diego State University Library), and in 2005 was presented with a Lifetime Achievement Award from the University of Arizona's College of Engineering. [2]

Engineering achievements

Based on his participation in the basic circuit design, definition, and system design of the Motorola 6800 microprocessor and supporting computer chips, Mensch is a co-holder of several 6800 family patents, including the 6800 central processing unit (CPU), 6820/21 Peripheral Interface Adapter (PIA), 6850 Asynchronous Communications Interface Adapter (ACIA), and 6860 modem chip. He was the sole IC design engineer of the 6820/21 PIA, which was the first peripheral IC to have bit-programmable input/output (I/O). [2]

Before the 6800 family, Mensch had worked on the Mostek 5065 processor.[ citation needed ]

MOS 6502

Along with three other engineers at MOS Technology, Mensch holds the patent on the decimal correct circuitry in the 6502 CPU. He was responsible for the design of basic circuits, oscillator, and buffer, transistor sizing, and instruction decode logic, wishing to minimize the number of levels of logic to achieve faster operation. During this time, when it was common to make errors during design, Chuck Peddle had praised Mensch as a skillfull designer and engineer: [4]

«He built seven different chips without ever having an error, almost all done by hand. When I tell people that, they don't believe me, but it's true. This guy is a unique person. He is the best layout guy in the world.» [4]

Before leaving MOS Technology in 1977, Mensch became their microprocessor design manager.

Western Design Center

Shortly after Mensch founded the Western Design Center (WDC) in 1978, Commodore International contracted the company to develop what they called a "macro-micro", a macro-programmed complementary metal–oxide–semiconductor (CMOS) processor that could be used in a small and powerful calculator. However, WDC was unable to complete the project, and Commodore ended their relationship with the new company. [5] Mensch claimed that Commodore never intended to use his design, and were instead seeking leverage to get a better deal for competing chips from Japanese producer Toshiba. [6]

The first major effort of Mensch and his team was developing the WDC 65C02, an enhanced version of the NMOS 6502 microprocessor. The 65C02, in addition to being implemented in CMOS circuit technology that reduced power use and improved noise immunity, added some new instructions, and corrected several defects in the NMOS 6502. The 65C02 was subsequently adopted for use in the Apple IIc computer and, later, in an enhanced version of the Apple IIe.

Mensch's next design, which was to become an important product at WDC, was a 65C02-compatible 16-bit microprocessor, the 65C816, later designated W65C816S. The 65C816's design came about following consultation with Apple and was adopted by them for use in the Apple IIGS computer. The 65C816 was later chosen as the core of the Ricoh 5A22 processor that powered the Super Nintendo Entertainment System.

Mensch developed the Mensch Computer as a means to promote the W65C816S microprocessor. It was a system designed around the WDC W65C265S microcontroller, which contains a W65C816S core. The computer, which includes the Mensch Works software suite, was produced for a time by WDC and was made for hobby and education uses.

Chuck Peddle and Bill Mensch are regarded as personal computer pioneers, because both the 6502 technology and business model were instrumental in helping launch the personal computer revolution. [7] [8]

Personal life

Mensch has five children and resides with his wife, Dianne, in Superstition Mountain, Arizona. [2]

Related Research Articles

<span class="mw-page-title-main">Integrated circuit</span> Electronic circuit formed on a small, flat piece of semiconductor material

An integrated circuit (IC), also known as a microchip, computer chip, or simply chip, is a small electronic device made up of multiple interconnected electronic components such as transistors, resistors, and capacitors. These components are etched onto a small piece of semiconductor material, usually silicon. Integrated circuits are used in a wide range of electronic devices, including computers, smartphones, and televisions, to perform various functions such as processing and storing information. They have greatly impacted the field of electronics by enabling device miniaturization and enhanced functionality.

<span class="mw-page-title-main">Microprocessor</span> Computer processor contained on an integrated-circuit chip

A microprocessor is a computer processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit (CPU). The IC is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system.

<span class="mw-page-title-main">MOS Technology 6502</span> 8-bit microprocessor from 1975

The MOS Technology 6502 is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. The design team had formerly worked at Motorola on the Motorola 6800 project; the 6502 is essentially a simplified, less expensive and faster version of that design.

<span class="mw-page-title-main">Motorola 6800</span> 8-bit microprocessor

The 6800 is an 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the M6800 Microcomputer System that also included serial and parallel interface ICs, RAM, ROM and other support chips. A significant design feature was that the M6800 family of ICs required only a single five-volt power supply at a time when most other microprocessors required three voltages. The M6800 Microcomputer System was announced in March 1974 and was in full production by the end of that year.

<span class="mw-page-title-main">Motorola 6809</span> 8-bit microprocessor

The Motorola 6809 ("sixty-eight-oh-nine") is an 8-bit microprocessor with some 16-bit features. It was designed by Motorola's Terry Ritter and Joel Boney and introduced in 1978. Although source compatible with the earlier Motorola 6800, the 6809 offered significant improvements over it and 8-bit contemporaries like the MOS Technology 6502, including a hardware multiplication instruction, 16-bit arithmetic, system and user stack registers allowing re-entrant code, improved interrupts, position-independent code and an orthogonal instruction set architecture with a comprehensive set of addressing modes.

<span class="mw-page-title-main">MOS Technology</span> Semiconductor company based in Pennsylvania, U.S.

MOS Technology, Inc. ("MOS" being short for Metal Oxide Semiconductor), later known as CSG (Commodore Semiconductor Group) and GMT Microelectronics, was a semiconductor design and fabrication company based in Audubon, Pennsylvania. It is most famous for its 6502 microprocessor and various designs for Commodore International's range of home computers.

In computer architecture, 8-bit integers or other data units are those that are 8 bits wide. Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. Memory addresses for 8-bit CPUs are generally larger than 8-bit, usually 16-bit. 8-bit microcomputers are microcomputers that use 8-bit microprocessors.

<span class="mw-page-title-main">KIM-1</span> Single-board computer produced by MOS Technology

The KIM-1, short for Keyboard Input Monitor, is a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976. It was very successful in that period, due to its low price and easy-access expandability.

<span class="mw-page-title-main">Chuck Peddle</span> American electrical engineer (1937–2019)

Charles Ingerham Peddle was an American electrical engineer best known as the main designer of the MOS Technology 6502 microprocessor, the KIM-1 single-board computer, and its successor, the Commodore PET personal computer, both based on the 6502.

In computer engineering, Halt and Catch Fire, known by the assembly language mnemonic HCF, is an idiom referring to a computer machine code instruction that causes the computer's central processing unit (CPU) to cease meaningful operation, typically requiring a restart of the computer. It originally referred to a fictitious instruction in IBM System/360 computers, making a joke about its numerous non-obvious instruction mnemonics.

<span class="mw-page-title-main">Western Design Center</span> American company

The Western Design Center (WDC), located in Mesa, Arizona, is a company which develops intellectual property for, and licenses manufacture of, MOS Technology 65xx based microprocessors, microcontrollers (µCs), and related support devices. WDC was founded in 1978 by a former MOS Technology employee and coholder of the MOS Technology 6502 patent, Bill Mensch.

<span class="mw-page-title-main">MOS Technology 6522</span> Microprocessor I/O port controller IC

The MOS Technology 6522 Versatile Interface Adapter (VIA) is an integrated circuit that was designed and manufactured by MOS Technology as an I/O port controller for the 6502 family of microprocessors. It provides two bidirectional 8-bit parallel I/O ports, two 16-bit timers, and an 8-bit shift register for serial communications or data conversion between serial and parallel forms. The direction of each bit of the two I/O ports can be individually programmed. In addition to being manufactured by MOS Technology, the 6522 was second sourced by other companies including Rockwell and Synertek.

The 6551Asynchronous Communications Interface Adapter (ACIA) is an integrated circuit made by MOS Technology. It served as a companion UART chip for the widely popular 6502 microprocessor. Intended to implement RS-232, its specifications called for a maximum speed of 19,200 bits per second with its onboard baud-rate generator, or 125 kbit/s using an external 16x clock. The 6551 was used in several computers of the 1970s and 1980s, including the Commodore PET and Plus/4. It was also used by Apple Computer on the Apple II Super Serial Card, and by Radio Shack on the Deluxe RS-232 Program Pak for their TRS-80 Color Computer.

<span class="mw-page-title-main">WDC 65C02</span> CMOS microprocessor in the 6502 family

The Western Design Center (WDC) 65C02 microprocessor is an enhanced CMOS version of the popular nMOS-based 8-bit MOS Technology 6502. It uses less power than the original 6502, fixes several problems, and adds new instructions. The power usage is on the order of 10 to 20 times less than the original 6502 running at the same speed; its reduced power consumption has made it useful in portable computer roles and industrial microcontroller systems. The 65C02 has also been used in some home computers, as well as in embedded applications, including medical-grade implanted devices.

<span class="mw-page-title-main">Depletion-load NMOS logic</span> Form of digital logic family in integrated circuits

In integrated circuits, depletion-load NMOS is a form of digital logic family that uses only a single power supply voltage, unlike earlier NMOS logic families that needed more than one different power supply voltage. Although manufacturing these integrated circuits required additional processing steps, improved switching speed and the elimination of the extra power supply made this logic family the preferred choice for many microprocessors and other logic elements.

<span class="mw-page-title-main">WDC 65C265</span> 16-bit CMOS microcontroller

The Western Design Center (WDC) W65C265S is a 16-bit CMOS microcontroller based on a W65C816S processor core, which is a superset of the MOS Technology 6502 processor.

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<span class="mw-page-title-main">Synertek</span>

Synertek, Inc. was an American semiconductor manufacturer founded in 1973. The initial staff consisted of Bob Schreiner, Dan Floyd, Jack Balletto, and Gunnar Wetlesen and Zvi Grinfas. Schreiner, Floyd, Balletto and Wetlesen were all formerly of Fairchild Semiconductor, and Synertek is thus one of the many "Fairchildren". The company became a major vendor during the late 1970s and early 1980s on the strength of their licensed production of the MOS 6502, one of the most successful microprocessors of the era. Synertek won supply deals with Apple Computer and Atari, who would produce millions of home computer and games consoles with Synertek 6502's inside.

<span class="mw-page-title-main">WDC 65C816</span> 8/16-bit microprocessor

The W65C816S is a 16-bit microprocessor (MPU) developed and sold by the Western Design Center (WDC). Introduced in 1983, the W65C816S is an enhanced version of the WDC 65C02 8-bit MPU, itself a CMOS enhancement of the venerable MOS Technology 6502 NMOS MPU. The 65C816 is the CPU for the Apple IIGS and, in modified form, the Super Nintendo Entertainment System.

References

  1. Mensch, William (October 9, 1995). "Interview with William Mensch (Silicon Genesis oral history project)" (Interview). Interviewed by Rob Walker. Stanford University. Archived from the original on March 4, 2016. Retrieved March 10, 2020.
  2. 1 2 3 4 "WDC Founder". Mesa, Arizona: The Western Design Center, Inc. 2012. Archived from the original on 8 May 2013. Retrieved 2020-03-10.
  3. "Notable Alumni". Sigma Pi Fraternity, International.
  4. 1 2 "research!rsc: The MOS 6502 and the Best Layout Guy in the World". research.swtch.com. Retrieved December 20, 2022.
  5. Archived at Ghostarchive and the Wayback Machine : Peddle, Chuck (June 12, 2014). Oral History of Chuck Peddle. Interviewed by Doug Fairbairn, Stephen Diamond. Event occurs at 1:53:00.
  6. Mench, Bill (October 12, 2020). Bill Mensch The Commodore Years (directors cut). Interviewed by Brien Stuart.
  7. "25 Microchips That Shook the World". IEEE Spectrum. Institute of Electrical and Electronics Engineers.
  8. Weyhrich, Steven (January 10, 2011). "Digging Into the 6502". Apple II History. WordPress. Retrieved March 10, 2020.

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