Internal Architecture of 8085 The internal architecture describes various internal components that make the 8085 and their interconnect. Figure 3.1 shows the internal architecture of 8085   Different internal components of 8085 are given and described in following section: Arithmetic & Logic Unit General Purpose Registers Instruction Register (IR)  Instruction Decoding Timing and control unit Internal Bus or data path Interrupt Control unit for externally initiated signals Serial I/O Control unit Address Incremented / Decremented   Arithmetic & Logic Unit (ALU):  The purpose of ALU is to perform the arithmetic, logical, shift and comparison operations on the data and produce the result. The status of the current operation is stored in the status result which can be used in programming for decision making and for

8085 introduction The 8085 is an 8-bit microprocessor was introduced in year 1977 by Intel require +5 Volt power supply to operate. It  is built using approximately 6500 transistors and the design is based on standard Von Neumann architecture. It was binary-compatible with its predecessor Intel 8080. It requires less supporting hardware, thus allowing simpler and less expensive microcomputer systems to be built. 8085 was basically designed for control applications and hence saw a long life as a controller. Features: 8085 is a 40-pin IC which was introduced by Intel corporation in 1977 It is an 8-bit microprocessor Total of 74 instructions are supported. OPCODE length is 8-bit, so there are 256 different opcodes. All general purpose registers are 8-bits wide. It is