MCS-8/80/85

History

The MCS-80 product family was introduced in March of 1974 and included the world’s first true generalpurpose microprocessor, the Intel 8080. The 8080 was used in the Altair 8800, the first affordable personal computer.
The MCS-85 product family was introduced in March 1976 and included the Intel 8085 microprocessor. The 8085 was designed to use a single five-volt power supply as opposed to the 8080, which required three (+5V, +12V, and –5V). The 8085 was 100% software compatible with the 8080A. The 8085 incorporated all the features of the 8224 clock generator and 8228 system controller. The 8085 along with the 8156 RAM and 8255/8755 ROM/EPROM constituted a complete system. The on-chip address latch of 8155/8355/8755 memory chips allowed a direct interface with the 8085.

Intel MCS-80/85 Family Products 

Part	Description	Year	Photo
8008	8-bit Microprocessor	April 1972
8080	8-bit Microprocessor	April 1974
8080A	8-bit Microprocessor	Early 1975
8080B	8-bit Microprocessor	2nd Qtr 1978
8085	8-bit Microprocessor	March 1976
8085A	8-bit Microprocessor	1978
8085AH	8-bit Microprocessor	1981-83
8155	2048-bit (256 x 8) Static RAM w/I/O Ports and Timer, CE Active Low	1977
8155H	2048-bit (256 x 8) Static RAM w/I/O Ports and Timer, CE Active Low	1982
8156	2048-bit (256 x 8) Static RAM w/I/O Ports and Timer, CE Active High	1977
8156H	2048-bit (256 x 8) Static RAM w/I/O Ports and Timer, CE Active High	1982
8185	8192-bit (1024 x 8) Static RAM for MCS-85™	1978-79
8218	Bipolar Microcomputer Bus Controller for MCS-80™	1979-80
8219	Bipolar Microcomputer Bus Controller for MCS-85™	1979-80
8224	Single Chip Clock Generator/Driver for 8080A CPU	1974
8228/3228	System Controller and Bus Driver for 8080A CPU	1975
8231	Arithmetic Processing Unit	1980
8231A	Arithmetic Processing Unit	1981-83
8232	Floating Point Processor	1980
8238/3238	System Controller and Bus Driver w/Advanced IOW/MEMW for 8080A CPU	1976
8355	16,384-bit (2048 x 8) ROM with I/O	1977-78
8755	16,384-bit (2048 x 8) EPROM with I/O	1976-77
8755A	16,384-bit (2048 x 8) EPROM with I/O	1978-79
8801	Clock Generator Crystal for 8224/8080A	1975-77

The original 8080 had an issue that prevented it from working with external TTL components as intended. This was fixed with the introduction of the "A" versions.

Part	Frequency	Description	Photo
8080	500 kHz - 2.08 MHz	MPU, Original, has compatibility issues with TTL
8080A	500 kHz - 2.08 MHz	MPU
8080A-1	500 kHz - 3.12 MHz	MPU
8080A-2	500 kHz - 2.63 MHz	MPU
8224		clock generator & driver
8801		clock generator crystal
8228		system controller & bus driver
8238		system controller & bus driver
8257		Programmable DMA Controller
8259		Programmable Interrupt Controller
8279		Programmable Keyboard/Display Controller
8271		Programmable Floppy Disk Controller
8222		Dynamic RAM Refresh Controller
8205		1 Of 8 Binary Decoder
8210		TTL To MOS Shifter & High Voltage Clock Driver
8212		8 Bit I/O Port
8214		Priority Interrupt Control Unit
8216		4 Bit Parallel Bidirectional Bus Driver
8251A		Improved Programmable Communication Interface
8253		Programmable Interval Timer
8255		Programmable Peripheral Interface
8255A		Improved Programmable Peripheral Interface

Military Specs

The following are military specs versions.

Part	Frequency	Description	Photo
M8080A	500 kHz - 2.08 MHz	MPU
M8224		clock generator & driver
M8228		system controller & bus driver
M8238		system controller & bus driver

Memory

Additional memory components that was used with the MCS-80