Interconnection of Networks: With the concept that impedance in series are additive and admittance in parallel are additive, we can easily solve the series and parallel combination of networks in terms of Z and Y parameters respectively. Networks can be connected in: Parallel connection Series Connection Parallel Connection of two-port networks We know the basic […]
8279 Keyboard/Display Interface
Keyboard Types Mechanical key switches Membrane type: with advantage that they can be made very thin and sealed Capacitive Type: When a key is pressed the capacitance between the plates varies. Hall effect: No mechanical contact. It take advantage of the deflection of a moving charge by a magnetic field. Keyboard Circuit connection and Interfacing […]
Inter-relationship between the two-port Parameters
Inter-relationship between the two-port Parameters The following steps of operations can be used for the transformation one set of parameters in terms of other set of parameters: Step 1. Write the standard equations for both sets. Step 2. Solve or rearrange the second set of equations and writing them in terms of the independent variables of 1st […]
Reciprocity of Parameters
Reciprocity Condition in two port Parameters Reciprocity Theorem states that the two networks are said to be reciprocal of each other if the ratio of the source voltage t one port to response (current) in other branch remain unchanged upon interchanging the position of the excitation and the response From Network-1, the Response to Excitation […]
Transmission Parameters
Transmission Parameters: A network is an interconnection of basic electrical elements. A network is called an electric circuit when it has current and voltage sources connected to it. Thus an electric is a closed energized network. Figure below shows an electric network and an electrical circuit. Two-Port Network We can write the equations for the […]
8259 Priority Interrupt Controller
8259 Programmable Interrupt Controller The Intel 8259A programmable Interrupt Controller (PIC) is one of the most common interrupt controller used in IBM PCs. It can handle eight vectored priority interrupts for the CPU. It is a 28 pin DIP package and requires a single +5V DC supply for its operation. It is designed to minimize […]
Introduction to Interrupt System
Interrupts Interrupt is one of the most common methods for an external device to communicate with the processor. In small systems, for example, we might read ASCII characters on interrupt basis, count interrupt from a timer to produce real time clock or seconds, minutes and hours; detect several emergency conditions on interrupt basis. Figure-1 below […]
8255 PPI(Programmable Peripheral Interface)
8255 Programmable Peripheral Interface 8255 is a programmable peripheral interface IC which is used as an interface between the external device and the microprocessor for parallel communication. This IC is a 40-pi IC having three ports known as Port-A(PA), Port-B(PB) and Port-C(PC). these ports can operate in various modes. the complete details is given in […]
Introduction to Network parameters
A network is an interconnection of basic electrical elements. A network is called an electric circuit when it has current and voltage sources connected to it. Thus an electric is a closed energized network. Figure below shows an electric network and an electrical circuit.A Terminal is an entry or exit point for a current, and […]
8254 Software-Programmable Timer/Counter
The Intel 8254 is a counter/timer device designed to solve the common timing control problems in microcomputer system design. It provides three independent 16-bit counters, each capable of handling clock inputs up to 10 MHz. All modes are software programmable. The 8254 uses HMOS technology and comes in a 24-pin plastic or CERDIP package. General […]
