8085 is pronounced as "eighty-eighty-five" microprocessor. It is an 8-bit microprocessor designed by Intel in 1977 using NMOS technology.
It has the following configuration:
• 8-bit data bus
• 16-bit address bus, which can occupy up to 64 KB
• A 16-bit program counter
•A 16-bit stack pointer
• Six 8-bit registers arranged in pairs: BC, DE, HL
• Requires +5 V power to operate with a 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:
Accumulator
It is an 8-bit register that is used to perform arithmetic, logic, I / O and LOAD / STORE operations. It is connected to the internal data bus and ALU.
Logical arithmetic unit
As its name suggests, it performs arithmetic and logical operations like Addition, Subtraction, Y, O, etc. in 8-bit data.
General Purpose Record
There are 6 general purpose registers on the 8085 processor, ie B, C, D, E, H, and L. Each register can contain 8-bit data.
These registers can work in pairs to contain 16-bit data and their pairing combination is like B-C, D-E, and H-L.
Program counter
It is a 16-bit register used to store the location of the memory address of the next instruction to execute. The microprocessor increments the program each time an instruction is executed, so that the program counter indicates the memory address of the next instruction to be executed.
Battery Pointer
It is also a 16-bit register that works as a stack, which is always increased / decreased by 2 during push & pop operations.
Temporary record
It is an 8-bit register, which contains the temporal data of arithmetic and logic operations.
Register Register
It is an 8-bit register that has five 1-bit flip-flops, which has 0 or 1 depending on the result stored in the accumulator.
These are the set of 5 flip-flops -
• Signals)
• Zero (Z)
• Auxiliary load (AC)
• Parity (P)
• Carrying ©