1 Introduction to Microprocessor 8085
Microprocessor is a electronic chip, that functions as the central processing unit of a computer.
For example: Washing machines, microwave ovens, mobile phones etc.
Its advance applications are Radar, Satellites, flights.
All processors are use the basic concept of stored program execution. program or instructions are stored sequentially in the memory. Every microprocessor has its own associated set of instructions. Instruction set for microprocessor is in two forms one in mnemonic, which is comparatively easy to understand and the other is binary machine code.
The Intel 8085 ("eighty-eighty-five") is an 8-bit microprocessor introduced by Intel in 1977. The 8085 is a conventional von Neumann design based on the Intel 8080. It is designed by using nmos technology. The "5" in the model number came from the fact that the 8085 requires only a +5-Volt (V) power supply. rather than requiring the +5 V, −5 V and +12 V supplies the 8080 needed. It has 8 bit data bus and 16 bit address bus. it can work upto 5 MHz frequency. It has 40 pins in its chip. Lower order address bus is multiplexed with data bus to minimize the chip size.
The 8085 has extensions to support new interrupts, with three maskable interrupts (RST 7.5, RST 6.5 and RST 5.5), one non-maskable interrupt (TRAP), and one externally serviced interrupt (INTR). The RST n.5 interrupts refer to actual pins on the processor, a feature which permitted simple systems to avoid the cost of a separate interrupt controller.