Intel 8042
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The MCS-48
microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable i ...
series,
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
's first microcontroller, was originally released in 1976. Its first members were 8048, 8035 and 8748. The 8048 is probably the most prominent member of the family. Initially, this family was produced using NMOS (n-type metal–oxide–semiconductor) technology. In the early 1980s, it became available in
CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFE ...
technology. It was manufactured into the 1990s to support older designs that still used it. The MCS-48 series has a modified Harvard architecture, with internal or external program
ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * R ...
and 64–256 bytes of internal (on-chip) RAM. The I/O is mapped into its own
address space In computing, an address space defines a range of discrete addresses, each of which may correspond to a network host, peripheral device, disk sector, a memory cell or other logical or physical entity. For software programs to save and retrieve st ...
, separate from programs and data. Though the MCS-48 series was eventually replaced by the very successful
MCS-51 The Intel MCS-51 (commonly termed 8051) is a single chip microcontroller (MCU) series developed by Intel in 1980 for use in embedded systems. The architect of the Intel MCS-51 instruction set was John H. Wharton. Intel's original versions were p ...
series, it remained quite popular even by the year 2000 due to its low cost, wide availability, memory-efficient one-byte instruction set, and mature development tools. Because of this, it is used in high-volume, cost-sensitive consumer electronics devices such as TV remotes, computer keyboards, and toys.


Variants

The 8049 has 2 KB of masked
ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * R ...
(the 8748 and 8749 had EPROM) that can be replaced with a 4 KB external ROM, as well as 128 
byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...
s of RAM and 27  I/O ports. The microcontroller's
oscillator Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...
block divides the incoming clock into 15 internal phases, thus with its 11 
MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
max. crystal one gets 0.73  MIPS (of one-clock instructions). Some 70% of instructions are single byte/cycle ones, but 30% need two cycles and/or two bytes, so the raw performance would be closer to 0.5 MIPS.


Uses

The Tandy/Radio Shack TRS-80 Model II, released in 1979, used the 8021 in its keyboard. The 8021 allowed the Model II to be the first desktop computer system with a separate detachable lightweight keyboard connected with by a single thin flexible wire, and likely the first keyboard to use a dedicated microprocessor, both attributes that would be copied years later by Apple and IBM. The 8021 processor scans the key matrix, converts switch closures to an 8-bit code and then transmits that code serially to the keyboard interface on the main system. The 8021 will also accept commands to turn indicator LEDs on or off. This was all done with just four chips, a remarkable feat at the time. The 8021 was also used in the keyboards for the TRS-80 Model 12, 12B, 16, 16B and the Tandy 6000/6000HD. The original
IBM PC keyboard The keyboard for IBM PC-compatible computers is standardized. However, during the more than 30 years of PC architecture being frequently updated, many keyboard layout variations have been developed. A well-known class of IBM PC keyboards is the Mo ...
used an 8048 as its internal
microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable i ...
. The PC AT replaced the PC's Intel 8255 peripheral interface chip at I/O port addresses with an 8042 accessible through port addresses and . As well as managing the keyboard interface, the 8042 controlled the A20 line gating function for the AT's Intel 80286 CPU and could be commanded by software to reset the 80286 (unlike the
80386 The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistorsprotected mode In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units (CPUs). It allows system software to use features such as virtual memory, paging and safe multi-tasking d ...
back to
real mode Real mode, also called real address mode, is an operating mode of all x86-compatible CPUs. The mode gets its name from the fact that addresses in real mode always correspond to real locations in memory. Real mode is characterized by a 20-bit seg ...
except by being reset). Later PC compatibles integrate the 8042's functions into their super I/O devices. The 8048 was used in the Magnavox Odyssey²
video game console A video game console is an electronic device that Input/output, outputs a video signal or image to display a video game that can be played with a game controller. These may be home video game console, home consoles, which are generally placed i ...
, the
Korg Trident This is a list of products manufactured by Korg Incorporated, a Japanese company that produces electronic musical instruments, audio processors and guitar pedals, recording equipment, and electronic tuners. 1960s 1963 * Donca-Matic DA-20: Rhyt ...
series, and the Korg Poly-61, Roland Jupiter-4 and
Roland ProMars The Roland Jupiter-4 (JP-4) was an analog synthesizer manufactured by the Roland Corporation between 1978 and 1981. It was notable as the company's first self-contained polyphonic synthesizer, and for employing digital control of analog cir ...
analog synthesizers. The Sinclair QL used the closely related Intel 8049 to manage its keyboard, joystick ports, RS-232 inputs and audio. The ROM-less 8035 variant was used in
Nintendo is a Japanese Multinational corporation, multinational video game company headquartered in Kyoto, Japan. It develops video games and video game consoles. Nintendo was founded in 1889 as by craftsman Fusajiro Yamauchi and originally produce ...
's arcade game '' Donkey Kong'' to generate the background music.


Derived microcontrollers

Philips Semiconductors (now
NXP NXP Semiconductors N.V. (NXP) is a Dutch semiconductor designer and manufacturer with headquarters in Eindhoven, Netherlands. The company employs approximately 31,000 people in more than 30 countries. NXP reported revenue of $11.06 billion in 2 ...
) owned a license to produce this series and developed their MAB8400-family based on this architecture. These were the first microcontrollers with an integrated
I²C I2C (Inter-Integrated Circuit, ), alternatively known as I2C or IIC, is a synchronous, multi-controller/multi-target (master/slave), packet switched, single-ended, serial communication bus invented in 1982 by Philips Semiconductors. It is wide ...
-interface and were used in the first
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
( Magnavox in the US) Compact Disc players (e.g. the CD-100).Datasheet (pdf)
Philips MAB8400-Family second sources"> File:KL USSR KM1816BE i8748 Black Background.jpg, Kvazar Kiev KM1816VE48 (Soviet Union) File:Mitsubishi M5M80C39P-6.jpg,
Mitsubishi Electric , established on 15 January 1921, is a Japanese multinational electronics and electrical equipment manufacturing company headquartered in Tokyo, Japan. It is one of the core companies of Mitsubishi. The products from MELCO include elevators an ...
M5M80C39P-6 File:NS87PC48D.jpg,
National Semiconductor National Semiconductor was an American semiconductor manufacturer which specialized in analog devices and subsystems, formerly with headquarters in Santa Clara, California. The company produced power management integrated circuits, display drive ...
NS87PC48D File:NEC D8749HD.png, NEC μPD8749HD File:Ic-photo-Philips--MAF 8049H PB A064--(8049-MCU).JPG,
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
MAF 8049H File:Ic-photo-Signetics--SCN8048A-(8048-MCU).png, Signetics SCN8048A


See also

* HSE-49 Emulator


References


Bibliography

;MCS-48 * ''MCS-48 Single Component Microcomputer'', Applications Seminar Notebook, 1978, Intel Corporation. *
Lionel Smith, Cecil Moore: ''Serial I/O and Math Utilities for the 8049 Microcomputer''
Application Note AP-49, January 1979, Intel Corporation. * ''A High-Speed Emulator for Intel MCS-48 Microcomputers'', Application Note AP-55A, August 1979, Intel Corporation. * Phil Dahm, Stuart Rosenberg: ''Intel MCS-48 and UPI-41A Microcontrollers'', Reliability Report RR-25, December 1979, Intel Corporation. * ''Microcontroller Handbook'', Intel 1984, Order number 210918-002. * ''8-Bit Embedded Controllers'', Intel 1991, Order number 270645-003. ;UPI-41 * ''UPI-41A User's Manual'', Intel 1980, Order number 9800504-02 Rev. B. * * Johan Beaston, Jim Kahn: ''An 8741A/8041A Digital Cassette Controller'', Application Note AP-90, May 1980, Intel Corporation.


External links


MCS-48 family architecture
*
Computer History Museum, Intel 8048 Microcontroller Oral History Panel

Microcontroller NEC 8741 (image of the Silicon-Chip)
{{DEFAULTSORT:Intel Mcs-48 Computer-related introductions in 1976 Intel microcontrollers