The MCS-48
microcontroller 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
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which d ...
) technology. In the early 1980s, it became available in
CMOS technology. It was manufactured into the 1990s to support older designs that still used it.
The MCS-48 series has a
modified Harvard architecture
The modified Harvard architecture is a variation of the Harvard computer architecture that, unlike the pure Harvard architecture, allows the contents of the instruction memory to be accessed as data. Most modern computers that are documented as ...
, 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
* ...
and 64–256 bytes of internal (on-chip)
RAM
Ram, ram, or RAM may refer to:
Animals
* A male sheep
* Ram cichlid, a freshwater tropical fish
People
* Ram (given name)
* Ram (surname)
* Ram (director) (Ramsubramaniam), an Indian Tamil film director
* RAM (musician) (born 1974), Dutch
* ...
. The
I/O is mapped into its own
address space, separate from programs and data.
Though the MCS-48 series was eventually replaced by the very successful
MCS-51 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
* ...
(the 8748 and 8749 had
EPROM
An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of programmable read-only memory (PROM) chip that retains its data when its power supply is switched off. Computer memory that can retrieve stored data after a power s ...
) 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 uni ...
s of
RAM
Ram, ram, or RAM may refer to:
Animals
* A male sheep
* Ram cichlid, a freshwater tropical fish
People
* Ram (given name)
* Ram (surname)
* Ram (director) (Ramsubramaniam), an Indian Tamil film director
* RAM (musician) (born 1974), Dutch
* ...
and 27
I/O ports. The microcontroller's
oscillator 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
The TRS-80 Model II is a computer system launched by Tandy in October 1979, and targeted at the small-business market. It is not an upgrade of the original TRS-80 Model I, but a new system.
The Model II was succeeded by the compatible TRS-80 Mode ...
, 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 ...
used an 8048 as its internal
microcontroller. The
PC AT
The IBM Personal Computer/AT (model 5170, abbreviated as IBM AT or PC/AT) was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel 80 ...
replaced the PC's
Intel 8255
The Intel 8255 (or i8255) Programmable Peripheral Interface (PPI) chip was developed and manufactured by Intel in the first half of the 1970s for the Intel 8080 microprocessor. The 8255 provides 24 parallel input/output lines with a variety of pr ...
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
The A20, or address line 20, is one of the electrical lines that make up the system bus of an x86-based computer system. The A20 line in particular is used to transmit the 21st bit on the address bus.
A microprocessor typically has a number o ...
gating function for the AT's
Intel 80286
The Intel 80286 (also marketed as the iAPX 286 and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non- multiplexed address and data buses and also the ...
CPU and could be commanded by software to reset the 80286 (unlike the
80386 and later processors, the 80286 had no way of switching from
protected mode back to
real mode except by being reset). Later PC compatibles integrate the 8042's functions into their
super I/O
Super I/O is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a vari ...
devices.
The 8048 was used in the
Magnavox Odyssey²
The Magnavox Odyssey 2 (stylized as Magnavox Odyssey²), also known as Philips Odyssey 2, is a second generation home video game console that was released in 1978. It was sold in Europe as the Philips Videopac G7000, in Brazil and Peru as the P ...
video game console
A video game console is an electronic device that outputs a video signal or image to display a video game that can be played with a game controller. These may be home consoles, which are generally placed in a permanent location connected to ...
, the
Korg Trident series, and the
Korg Poly-61,
Roland Jupiter-4
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 circ ...
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 c ...
analog synthesizer
An analog (or analogue) synthesizer is a synthesizer that uses analog circuits and analog signals to generate sound electronically.
The earliest analog synthesizers in the 1920s and 1930s, such as the Trautonium, were built with a variety of ...
s. The
Sinclair QL
The Sinclair QL (for ''Quantum Leap'') is a personal computer launched by Sinclair Research in 1984, as an upper-end counterpart to the ZX Spectrum. The QL was aimed at the serious home user and professional and executive users markets from small ...
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's arcade game ''
Donkey Kong
is a video game franchise created by Shigeru Miyamoto and owned by Nintendo. It follows the adventures of a gorilla named Donkey Kong (character), Donkey Kong and his clan of other Ape, apes and monkeys. The franchise primarily consists of plat ...
'' to generate the background music.
Derived microcontrollers
Philips Semiconductors (now
NXP) 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 wi ...
-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
Magnavox (Latin for "great voice", stylized as MAGNAVOX) is an American electronics company that since 1974 has been a subsidiary of the Dutch electronics corporation Philips.
The predecessor to Magnavox was founded in 1911 by Edwin Pridham and ...
in the US)
Compact Disc players (e.g. the CD-100).
Datasheet (pdf)
Philips MAB8400-Family
second source
In the electronics industry, a second source is a company that is licensed to manufacture and sell components originally designed by another company (the first source).
It is common for engineers and purchasers to avoid components that are only av ...
s">
File:KL USSR KM1816BE i8748 Black Background.jpg, Kvazar Kiev KM1816VE48 (Soviet Union)
File:Mitsubishi M5M80C39P-6.jpg,
;MCS-48
* ''MCS-48 Single Component Microcomputer'', Applications Seminar Notebook, 1978, Intel Corporation.
*
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.