World Library  
Flag as Inappropriate
Email this Article

Intel MCS-48

Article Id: WHEBN0000060228
Reproduction Date:

Title: Intel MCS-48  
Author: World Heritage Encyclopedia
Language: English
Subject: Intel MCS-51, List of Sega arcade system boards, Instructions per second, C166 family, COP8
Collection: 1976 Introductions, Microcontrollers
Publisher: World Heritage Encyclopedia

Intel MCS-48

Intel 8048 microcontroller
The 8749 with UV EPROM
USSR KM1816BE48, an Intel 8748 clone.
An Intel 8049 microcontroller, as used in a HP3478A Multimeter. This chip was manufactured in the 48th week 1990.

The MCS-48 microcontroller (µC) series, Intel's first microcontroller, was originally released in 1976. Its first members were 8048, 8035 and 8748. Initially this family was produced using NMOS-technology, in the early 1980s it became available in CMOS-technology. It was still 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 and 64–256 bytes of internal (on-chip) RAM. The I/O is mapped into its own address space, separate from programs and data. The 8048 is probably the most prominent member of Intel's MCS-48 family of microcontrollers.

Though the MCS-48 series was eventually replaced by the very popular MCS-51 series, even at around year 2000 it remained 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 1
  • Uses 2
  • Literature 3
  • See also 4
  • External links 5
  • References 6


The 8049 has 2 KB of masked ROM (the 8748 and 8749 had EPROM) that can be replaced with a 4 KB external ROM, as well as 128 bytes of RAM and 27 I/O 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 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.

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-interface and were used in the first Philips (Magnavox in the US) Compact Disc players (e.g. the CD-100).[1]

Another variant, the ROM-less 8035, was used in Nintendo'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 × 8 ROM 64 × 8 RAM Subset of 8048, 20 pins, only 13 I/O lines
8021 1K × 8 ROM 64 × 8 RAM Subset of 8048, 28 pins, 21 I/O lines
8022 2K × 8 ROM 64 × 8 RAM Subset of 8048, A/D-converter
8035 none 64 × 8 RAM
8039 none 128 × 8 RAM
8040 none 256 × 8 RAM
8048 1K × 8 ROM 64 × 8 RAM
8049 2K × 8 ROM 128 × 8 RAM
8050 ext. ROM socket 256 × 8 RAM
8748 1K × 8 EPROM 64 × 8 RAM
8749 2K × 8 EPROM 128 × 8 RAM
8648 1K × 8 OTP EPROM 64 × 8 RAM Factory OTP EPROM
Device Internal Memory Remarks
8041 1K × 8 ROM 64 × 8 RAM Universal Peripheral Interface (UPI)
8041AH 1K × 8 ROM 128 × 8 RAM UPI
8741A 1K × 8 EPROM 64 × 8 RAM UPI, EPROM version of 8041
8741AH 1K × 8 OTP EPROM 128 × 8 RAM UPI, OTP EPROM version of 8041AH
8042AH 2K × 8 ROM 256 × 8 RAM UPI
8742 2K × 8 EPROM 128 × 8 RAM UPI, EPROM version
8742AH 2K × 8 OTP EPROM 256 × 8 RAM UPI, OTP EPROM version of 8042AH


The 8048 was used in the

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.

  1. ^ Datasheet (pdf) Philips MAB8400-Family
  2. ^ "Korg Poly-61 Service Manual". 
  3. ^ Gordon Reid (November 2004). "The History Of Roland, Part 1: 1930–1978". The History Of Roland. Sound On Sound Magazine. Retrieved 29 November 2010. 
  4. ^ "Section 4: Keyboard", Technical Reference: Personal Computer, Personal Computer Hardware Reference Library (Revised ed.),  
  5. ^ "Section 1: System Board", Technical Reference: Personal Computer AT, Personal Computer Hardware Reference Library, IBM, September 1985 


  • MCS-48 family architecture
  • Coprolite 8048 Projects
  • Computer History Museum, Intel 8048 Microcontroller Oral History Panel
  • Microcontroller NEC 8741 (image of the Silicium-Chip)

External links

See also

  • 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.
  • 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.


The original IBM PC keyboard used an 8048 as its internal microcontroller.[4] The PC AT replaced the PC's Intel 8255 peripheral interface chip at I/O port addresses 0x60-63 with an 8042 accessible through port addresses 0x60 and 0x64.[5] As well as managing the keyboard interface the 8042 controlled the A20 line of the AT's Intel 80286 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 devices.

. analog synthesizers [3]Roland ProMars and Roland Jupiter-4 [2]

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.