There are 5 interrupt signals in 8085 microprocessor: INTR, RST 7.5, RST 6.5, RST 5.5, TRAP. After the request is completed, the control goes back to the main program. When a microprocessor is executing a main program and whenever an interrupt occurs, the microprocessor shifts the control from the main program to process the incoming request. Following are the timing and control signals, which control external and internal circuits в€’ДЄs the name suggests it controls the interrupts during a process. It provides timing and control signal to the microprocessor to perform operations. Instruction decoder decodes the information present in the Instruction register. When an instruction is fetched from memory then it is stored in the Instruction register. Its bit position is shown in the following table в€’ D7 It is an 8-bit register having five 1-bit flip-flops, which holds either 0 or 1 depending upon the result stored in the accumulator. It is an 8-bit register, which holds the temporary data of arithmetic and logical operations.

It is also a 16-bit register works like stack, which is always incremented/decremented by 2 during push & pop operations. 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 a 16-bit register used to store the memory address location of the next instruction to be executed. These registers can work in pair to hold 16-bit data and their pairing combination is like B-C, D-E & H-L. There are 6 general purpose registers in 8085 processor, i.e. Arithmetic and logic unitДЄs the name suggests, it performs arithmetic and logical operations like Addition, Subtraction, AND, OR, etc. It is connected to internal data bus & ALU. It is an 8-bit register used to perform arithmetic, logical, I/O & LOAD/STORE operations. 8085 Microprocessor вЂ“ Functional UnitsДЁ085 consists of the following functional units в€’ Accumulator It is used in washing machines, microwave ovens, mobile phones, etc. Requires +5V supply to operate at 3.2 MHZ single phase clock.Six 8-bit registers arranged in pairs: BC, DE, HL.16-bit address bus, which can address upto 64KB.It is an 8-bit microprocessor designed by Intel in 1977 using NMOS technology.

8085 is pronounced as 'eighty-eighty-five' microprocessor.

8085 microprocessor architecture pdf