The Intel 8085 ("eighty-eighty-five") is an 8-bit microprocessor produced by Intel and introduced in March 1976. It is a software-binary compatible with the more-famous Intel 8080 with only two minor instructions added to support its added interrupt and serial input/output features.
It has the following configuration −
8-bit data bus
16-bit address bus, which can address upto 64KB
A 16-bit program counter
A 16-bit stack pointer
Six 8-bit registers arranged in pairs: BC, DE, HL
Requires +5V supply to operate at 3.2 MHZ single phase clock
It is used in washing machines, microwave ovens, mobile phones, etc.
8085 Microprocessor – Functional Units
8085 consists of the following functional units −
It is an 8-bit register used to perform arithmetic, logical, I/O & LOAD/STORE operations. It is connected to internal data bus & ALU.
Arithmetic and logic unit
As the name suggests, it performs arithmetic and logical operations like Addition, Subtraction, AND, OR, etc. on 8-bit data.
General purpose register
There are 6 general purpose registers in 8085 processor, i.e. B, C, D, E, H & L. Each register can hold 8-bit data.
These registers can work in pair to hold 16-bit data and their pairing combination is like B-C, D-E & H-L.
It is a 16-bit register used to store the memory address location of the next instruction to be executed. Microprocessor increments the program whenever an instruction is being executed, so that the program counter points to the memory address of the next instruction that is going to be executed.
It is also a 16-bit register works like stack, which is always incremented/decremented by 2 during push & pop operations.
It is an 8-bit register, which holds the temporary data of arithmetic and logical operations.