Intel MCS-48 - Variants

Variants

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 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.

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.

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 4K × 8 ROM 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