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.
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).
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.
|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||4K x 8 ROM||256 × 8 RAM|
|8748||1K × 8 EPROM||64 × 8 RAM|
|8749||2K × 8 EPROM||128 × 8 RAM|
|87P50||ext. ROM socket||256 × 8 RAM||has Piggy-back socket for 2758/2716/2732 EPROM|
|8648||1K × 8 OTP EPROM||64 × 8 RAM||Factory OTP EPROM|
|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 Magnavox Odyssey² video game console, the Korg Trident series, the Korg Poly-61,<ref>"Korg Poly-61 Service Manual" (PDF).</ref> Roland Jupiter-4 and Roland ProMars<ref name="SOS11-04">Gordon Reid (November 2004). "The History Of Roland, Part 1: 1930–1978". The History Of Roland. Sound On Sound Magazine. Retrieved 29 November 2010.</ref> analog synthesizers.
The original IBM PC keyboard used an 8048 as its internal microcontroller.<ref>"Section 4: Keyboard", Technical Reference: Personal Computer, Personal Computer Hardware Reference Library (Revised ed.), IBM, April 1984</ref> The PC AT replaced the PC's Intel 8255 periphera
- 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-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 family architecture
- Coprolite 8048 Projects at the Wayback Machine (archived 17 July 2014)
- Computer History Museum, Intel 8048 Microcontroller Oral History Panel
- Microcontroller NEC 8741 (image of the Silicium-Chip)
- Datasheet (pdf) Philips MAB8400-Family