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Intel 8085

General

General Information

The 8085 was the follow-on processor to the very successful Intel 8080A processor. The 8085 got its name because it was Intel’s first 5 volt microprocessor. The 8085 was 100% software compatible with the 8080A with increased systems performance. The initial 8085’s were based on NMOS technology and the later “H” versions were based on HMOS technology.

The 8085 incorporated all the features of the 8224 (clock generator) and the 8228 (system controller) increasing the level of system integration. The 8085 along with and 8156 RAM and 8355/8755 ROM/PROM constituted a complete system. The 8085 used a multiplexed Data Bus and required the 825X-5 support chips. The address was split between the 8-bit address bus and 8-bit data bus. The on-chip address latch of 8155/8355/8755 memory chips allowed a direct interface with the 8085.

The 8085 family is also referred to as the MCS-85.

Production

April, 1976

Designers Unknown

Architecture

Type Data Word Address Space Clock Instruct- ions Assists Reg’s  GP Reg’s Math Reg’s Index IO Ports   Stack Interrupts Memory
NMOS & HMOS,CPU

 

8-bit 64KB Base 3Mhz, (-2) 5Mhz, (-1) 6Mhz 48 Ext* 0 1 6 8-bit NA NA 4 Vectors NA

* Intel made a hardware multiply chip called the 8231 for the 8080/85

Standard Packages

Chip Name

Package

On-Chip Identification

Picture

General Comments

C8085

Purple/Tin CerDIP, 40-pin

C8085

C8085  

C8085A

Purple/Tin CerDIP, 40-pin

C8085A

C8085A  
C8085A-2 Purple/Gold CerDIP, 40-pin C8085A-2 C8085A-2  
C8085AH Purple/Gold CerDIP, 40-pin C8085AH

NA

 
C8085AH-2 Purple/Gold CerDIP, 40-pin C8085AH-2 C8085AH-2  
C8085AH-1 Purple/Gold CerDIP, 40-pin C8085AH-1

NA

 
D8085 Gray Ceramic, 40-pin DIP D8080

NA

 
D8085A Gray Ceramic, 40-pin DIP D8085A D8085A  
D8085A-2 Gray Ceramic, 40-pin DIP D8085A-2

NA

 
D8085AH Gray Ceramic, 40-pin DIP D8085AH D8085AH  
D8085AH-2 Gray Ceramic, 40-pin DIP D8085AH-2

NA

 
D8085AH-1 Gray Ceramic, 40-pin DIP D8085AH-1 D8085AH-1  
P8085A Black Resin, 40-pin DIP P8085A P8085A  
P8085A-2 Black Resin, 40-pin DIP P8085A-2

NA

 
P8085AH Black Resin, 40-pin DIP P8085AH P8085AH  
P8085AH-2 Black Resin, 40-pin DIP P8085AH-2 P8085AH-2  
P8085AH-1 Black Resin, 40-pin DIP P8085AH-1

NA

 

Modified Packages (I, M, L, and Q)

Chip Name

Package

On-Chip Identification

Picture

General Comments

ID8085AH

Gray Ceramic, 40-pin DIP

ID8085AH

ID8085AH  

Related Chips

Related Chips

Intel 8080

Second Sources

AMD, National Semiconductor, Mitsubishi, Toshiba, NEC, Siemens

Support Chips 8155 (2048-bit static MOS RAM with I/O Ports and Timer, CE Active Low), 8156 (Same 8155, but CE Active High), 8355 (16,384-bit ROM with I/O), 8755 (16,384-bit EPROM with I/O), 8251A (Programmable Communications Interface), 8253-5 (Programmable Interval Timer), 8255-5 (Programmable Peripheral Interface), 8257-5 (DMA Controller), 8259-5 (Interrupt Controller), 8279-5 (Keyboard/Display Interface)