Intel MCS-48
Encyclopedia
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
(µC) series, Intel's first microcontroller, was originally released in 1976. Its first members were 8048, 8035 and 8748.
The MCS-48 series has a Modified Harvard architecture
Modified Harvard architecture
The Modified Harvard Architecture is a variation of the Harvard computer architecture that allows the contents of the instruction memory to be accessed as if it were data...
, with internal or external program ROM and 64–256 bytes of internal (on-chip) RAM
Random-access memory
Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
. The I/O
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...
is mapped into its own address space
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.- Overview :...
, separate from programs and data. The 8048 is probably the most prominent member of Intel's MCS-48 family of microcontrollers. It was inspired by, and is somewhat similar to, the Fairchild F8
Fairchild F8
The Fairchild F8 was an 8-bit microprocessor created by Fairchild Semiconductor. It was introduced in 1975 and was "the world´s leading microprocessor in terms of CPU sales" in 1977.-Features:...
microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
.
Though the MCS-48 series was eventually replaced by the very popular Intel MCS-51
Intel 8051
The Intel MCS-51 is a Harvard architecture, single chip microcontroller series which was developed by Intel in 1980 for use in embedded systems. Intel's original versions were popular in the 1980s and early 1990s. While Intel no longer manufactures the MCS-51, binary compatible derivatives remain...
, even at the turn of the millennium it remains quite popular, due to its low cost, wide availability, memory efficient one-byte instruction set, and mature development tools. Because of this it is much used in high-volume consumer electronics devices such as TV sets, TV remotes, toys, and other gadgets where cost-cutting is essential.
Variants
The 8049 has 2 KB of masked ROMRead-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
(the 8748 and 8749 had EPROM
EPROM
An EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
) that can be replaced with a 4 KB external ROM, as well as 128 byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
s of RAM
Random-access memory
Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
and 27 I/O
I/O
I/O may refer to:* Input/output, a system of communication for information processing systems* Input-output model, an economic model of flow prediction between sectors...
ports. The µC's oscillator block divides the incoming clock into 15 internal phases, thus with its 11 MHz max. crystal one gets 0.73 MIPS (of one-clock instruction
Instruction set
An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...
s). Some instructions are single byte/cycle ones, but a large amount of opcodes need two cycles and/or two bytes, so the raw performance would be closer to 0.5 MIPS.
Another variant, the ROM-less 8035, was used in Nintendo
Nintendo
is a multinational corporation located in Kyoto, Japan. Founded on September 23, 1889 by Fusajiro Yamauchi, it produced handmade hanafuda cards. By 1963, the company had tried several small niche businesses, such as a cab company and a love hotel....
's arcade game Donkey Kong. Although not being a typical application for a microcontroller, its purpose was to generate the background music of the game.
The Intel 8748 has on-chip clock oscillator, 2 8-bit timers, 27 I/O ports, 64 bytes of RAM and 1 KB of EPROM. A version with 2 KB EPROM and 128 bytes RAM was also available under the 8749 number.
Device Internal Memory Remarks
8020 1K x 8 ROM 64 x 8 RAM Subset of 8048, 20 pins, Only 13 I/O Lines
8021 1K x 8 ROM 64 x 8 RAM Subset of 8048, 28 pins ,21 I/O Lines
8022 2K x 8 ROM 64 x 8 RAM Subset of 8048, A/D-converter
8035 none 64 x 8 RAM
8039 none 128 x 8 RAM
8040 none 256 x 8 RAM
8048 1K x 8 ROM 64 x 8 RAM
8049 2K x 8 ROM 128 x 8 RAM
8050 4K x 8 ROM 256 x 8 RAM
8748 1K x 8 EPROM 64 x 8 RAM
8749 2K x 8 EPROM 128 x 8 RAM
8648 1K x 8 OTP EPROM 64 x 8 RAM Factory OTP EPROM
Device Internal Memory Remarks
8041 1K x 8 ROM 64 x 8 RAM Universal Peripheral Interface (UPI)
8041AH 1K x 8 ROM 128 x 8 RAM UPI
8741A 1K x 8 EPROM 64 x 8 RAM UPI, EPROM version of 8041
8741AH 1K x 8 OTP EPROM 128 x 8 RAM UPI, OTP EPROM version of 8041AH
8042AH 2K x 8 ROM 256 x 8 RAM UPI
8742 2K x 8 EPROM 128 x 8 RAM UPI, EPROM version
8742AH 2K x 8 OTP EPROM 256 x 8 RAM UPI, OTP EPROM version of 8042AH
Uses
The 8048 was used in the Magnavox Odyssey²Magnavox Odyssey²
The Magnavox Odyssey², known in Europe as the Philips Videopac G7000, in Brazil as the Philips Odyssey, in the United States as the Magnavox Odyssey² and the Philips Odyssey², and also by many other names, is a video game console released in 1978.In the early 1970s, Magnavox was an innovator in the...
video game console
Video game console
A video game console is an interactive entertainment computer or customized computer system that produces a video display signal which can be used with a display device to display a video game...
, the Korg Trident series, the Korg Poly-61
Korg Poly-61
The Poly-61 is a programmable polyphonic synthesizer released by Korg in 1982, replacing the Polysix. It was notable as it was the first Korg synthesizer to feature a pushbutton user interface, dispensing from the Polysix's knobs and switches...
, Roland Jupiter-4
Roland Jupiter-4
The Roland Jupiter 4 was an analog synthesizer manufactured by the Roland Corporation of Japan between 1978 and 1981. It was notable as the company's first self-contained polyphonic synthesizer, and for containing digital control of analog circuits , allowing for such features as programmable...
and Roland ProMars analog synthesizer
Analog synthesizer
An analog or analogue synthesizer is a synthesizer that uses analog circuits and analog computer techniques to generate sound electronically. The earliest analog synthesizers in the 1920s and 1930s such as the Trautonium were built with a variety of vacuum-tube and electro-mechanical technologies...
s.
The original IBM PC keyboard
IBM PC keyboard
The keyboards for IBM PC compatible computers are standardized. However, during the 3-plus decades of PC architecture being constantly updated, multiple types of keyboard layout variations have been developed....
used an 8048 as its internal microcontroller. The PC AT
IBM Personal Computer/AT
The IBM Personal Computer AT, more commonly known as the IBM AT and also sometimes called the PC AT or PC/AT, was IBM's second-generation PC, designed around the 6 MHz Intel 80286 microprocessor and released in 1984 as machine type 5170...
replaced the PC's Intel 8255
Intel 8255
The Intel 8255 Programmable Peripheral Interface chip is a peripheral chip originally developed for the Intel 8085 microprocessor, and as such is a member of a large array of such chips, known as the MCS-85 Family. This chip was later also used with the Intel 8086 and its descendants.It was later...
peripheral interface chip at I/O port addresses 0x
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
60-63 with an 8042 accessible through port addresses 0x60 and 0x64. As well as managing the keyboard interface the 8042 controlled the A20 line
A20 line
The A20 or addressing line 20 is one of the plethora of 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....
of the AT's Intel 80286
Intel 80286
The Intel 80286 , introduced on 1 February 1982, was a 16-bit x86 microprocessor with 134,000 transistors. Like its contemporary simpler cousin, the 80186, it could correctly execute most software written for the earlier Intel 8086 and 8088...
CPU, and could be commanded by software to reset the 80286 (unlike the 80386
Intel 80386
The Intel 80386, also known as the i386, or just 386, was a 32-bit microprocessor introduced by Intel in 1985. The first versions had 275,000 transistors and were used as the central processing unit of many workstations and high-end personal computers of the time...
and later processors, the 80286 had no way of switching from protected mode
Protected mode
In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units...
back to real mode
Real mode
Real mode, also called real address mode, is an operating mode of 80286 and later x86-compatible CPUs. Real mode is characterized by a 20 bit segmented memory address space and unlimited direct software access to all memory, I/O addresses and peripheral hardware...
except by being reset). Later PC compatibles integrate the 8042's functions into their super I/O
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 variety of low-bandwidth devices...
devices.
Literature
MCS-48- MCS-48™ Single Component Microcomputer, Applications Seminar Notebook, 1978, Intel Corporation.
- MCS-48™ MICROCOMPUTER USER'S MANUAL, 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.
- Microprocessor Peripherals UPI-41A/41AH/42/42AH User's Manual, October 1993, Order number 231318-006, Intel Corporation.
- Johan Beaston, Jim Kahn: An 8741A/8041A Digital Cassette Controller, Application Note AP-90, May 1980, Intel Corporation.