In this tutorial, we will discuss the architecture, pin diagram and other key concepts of microprocessors. This input output interfacing 8085 microprocessor pdf is designed for all those readers pursing either Bachelor’s or Master’s degree in Computer Science.
It will help them understand the basic concepts related to Microprocessors. In this tutorial, all the topics have been explained from elementary level. Therefore, a beginner can understand this tutorial very easily. However if you have a prior knowledge of computer architecture in general, then it will be quite easy to grasp the concepts explained here.
The set of states a system can occupy is known as its state space. In a discrete system, the state space is countable and often finite, and the system’s internal behaviour or interaction with its environment consists of separately occurring individual actions or events, such as accepting input or producing output, that may or may not cause the system to change its state. Examples of such systems are digital logic circuits and components, automata and formal language, computer programs, and computers.
The output of a digital circuit or computer program at any time is completely determined by its current inputs and its state. Digital logic circuits can be divided into two types: combinational logic, whose output signals are dependent only on its present input signals, and sequential logic, whose outputs are a function of both the current inputs and the past history of inputs.
In sequential logic, information from past inputs is stored in electronic memory elements, such as flip-flops. The stored contents of these memory elements, at a given point in time, is collectively referred to as the circuit’s state and contains all the information about the past to which the circuit has access. Since each binary memory element, such as a flip-flop, has only two possible states, one or zero, and there is a finite number of memory elements, a digital circuit has only a certain finite number of possible states. If N is the number of binary memory elements in the circuit, the maximum number of states a circuit can have is 2N.
Similarly, a computer program stores data in variables, which represent storage locations in the computer’s memory. The contents of these memory locations, at any given point in the program’s execution, is called the program’s state.
In declarative programming languages, the program describes the desired results and doesn’t specify changes to the state directly. Serial programs operate on the incoming data characters or packets sequentially, one at a time. In some of these programs, information about previous data characters or packets received is stored in variables and used to affect the processing of the current character or packet. This is called a “stateful protocol” and the data carried over from the previous processing cycle is called the “state”.