Intel introduced this 8-bit microprocessor in1977, which was binary compatible with the Intel 8080, but the 8085 required less hardware to support it. This led to simpler, cheaper microcomputer systems.
The 8085 lasted for a long time as a control chip. It was designed into products such as the VT100 video and the DECtape controller in the 1970s. It served for several generations in the life of these products; in fact longer than its product life in desktop computers.
The 8085 used a conventional von Neuman design. As noted above, it was based on the Intel 808, but unlike that it did not multiplex state signals through to the data bus, but multiplexed the 8-bit data bus to the lower part of the 16-bit address bus.
It was a binary compatible successor to the 8080, with only a few minor changes to instructions to the 8085 over the 8080.
8085s used seven 8-bit registers titled A-H, and L. A is the 8-bit accumulator. The remaining six could be utilized as either three 16 bit register pairs or as independent byte registers.
In common with many other 8-bit processors, the instructions were encoded in a single byte for ease of use. Some were followed by one or two extra bytes of data; these could immediately be an operand, a port number or a memory address. It shares CALL and RET instructions with other, larger processors.
- Specification
- Outmoded
The 8085 lasted for a long time as a control chip. It was designed into products such as the VT100 video and the DECtape controller in the 1970s. It served for several generations in the life of these products; in fact longer than its product life in desktop computers.
The 8085 used a conventional von Neuman design. As noted above, it was based on the Intel 808, but unlike that it did not multiplex state signals through to the data bus, but multiplexed the 8-bit data bus to the lower part of the 16-bit address bus.
It was a binary compatible successor to the 8080, with only a few minor changes to instructions to the 8085 over the 8080.
8085s used seven 8-bit registers titled A-H, and L. A is the 8-bit accumulator. The remaining six could be utilized as either three 16 bit register pairs or as independent byte registers.
In common with many other 8-bit processors, the instructions were encoded in a single byte for ease of use. Some were followed by one or two extra bytes of data; these could immediately be an operand, a port number or a memory address. It shares CALL and RET instructions with other, larger processors.
